DRAFT DEVELOPMENT DOCUMENT
Including the Data Base for
EFFLUENT LIMITATIONS GUIDELINES (BATEA),
NEW SOURCE PERFORMANCE STANDARDS,
and
PRETREATMENT STANDARDS
for the
INORGANIC CHEMICALS MANUFACTURING
POINT SOURCE CATEGORY
Prepared for
Effluent Guidelines Division
Office of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D.C. 20460
Robert B. Schaffer. Director
Effluent Guidelines Division
G. E. Stigall, Acting Branch Chief
Inorganic Chemicals Branch
E. E. Martin
D. Hlustick
Project Officers
CONTRACT NO. 68-01-4492
BY
JACOBS ENGINEERING GROUP INC
JACOBS ENVIRONMENTAL DIVISION
251 SOUTH LAKE AVENUE
PASADENA CALIFORNIA 91101
APRIL 1979
-------
DRAFT DEVELOPMENT DOCUMENT
Including the Data Base for
EFFLUENT LIMITATIONS GUIDELINES (BATEA),
NEW SOURCE PERFORMANCE STANDARDS,
and
PRETREATMENT STANDARDS
for the
INORGANIC CHEMICALS MANUFACTURING
POINT SOURCE CATEGORY
Prepared for
Effluent Guidelines Division
Office of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D.C. 20460
Robert B. Schaffer, Director
Effluent Guidelines Division
G. E. Stigall, Acting Branch Chief
Inorganic Chemicals Branch
E. E. Martin
D. Hlustick
Project Officers
CONTRACT NO. 68-01-4492
BY
JACOBS ENGINEERING GROUP INC.
JACOBS ENVIRONMENTAL DIVISION
251 SOUTH LAKE AVENUE
PASADENA, CALIFORNIA 91101
-------
NOTICE
This document is a DRAFT CONTRACTOR'S REPORT. It includes
technical information submitted by the Contractor to the United
States Environmental Protection Agency (EPA) regarding the
subject industry. It is being distributed for review and comment
only. The report is not an official EPA publication and it has
not been reviewed by the Agency.
The report will be undergoing extensive review by EPA,
Federal and State agencies, public interest organizations, and
other interest groups and persons during the coming weeks.
The regulations to be published by EPA under Sections
301 (d) , 304 (b), and 306 of the Federal Water Pollution Control
Act, as amended, will be based in part, on the report and the
comments received on it. EPA will also be considering economic
and environmental impact information that is being developed.
Upon completion of the review and evaluation of the technical,
economic, and environmental information, an EPA report will be
issued at the time of proposed rule-making setting forth EPA's
preliminary conclusions regarding the subject industry. These
proposed rules will include proposed effluent guidelines and
standards, standards of performance, and pretreatment standards
applicable to the industry. EPA is making this draft
contractor's report available to encourage broad, public
participation, early in the rule-making process.
The report shall have standing in any EPA proceeding or
court proceeding only to the extent that it represents the views
of the Contractor who studied the subject industry and prepared
the information. It cannot be cited, referenced, or represented
in any respect in any such proceedings as a statement of EPA's
views regarding the subject industry.
U.S. Environmental Protection Agency
Office of Water and Hazardous Materials
Effluent Guidelines Division
Washington, D.C. 20460
-------
TABLE OF CONTENTS
Page
LIST OF FIGURES xiv
LIST OF TABLES xxii
1.0 CONCLUSIONS AND SUMMARY 1
1.1 PRIORITY POLLUTANTS 1
1.2 CONTROL AND TREATMENT TECHNOLOGY 1
1.3 COSTS OF ADDITIONAL IN-PLANT TREATMENT 2
1.4 SUBCATEGORIZATION 2
1.5 RESTUDY OF REMANDED REGULATIONS 3
2.0 RECOMMENDATIONS 4
3.0 INTRODUCTION 5
3.1 AUTHORITY 5
3.1.1 The Federal Water Pollution Control 5
Act Amendments
3.1.2 Court Remand of Regulations 6
3.1.3 The Settlement Agreement 8
3.2 GENERAL APPROACH AND METHODOLOGY 16
3.2.1 Industry Data Base Development and 16
Subcategorization Review
3.2.2 Screening and Verification Sampling 17
Programs
3.2.3 Engineering Evaluations 17
3.2.4 Treatment Systems Cost Estimates 17
4.0 SUBCATEGORIZATION REVIEW 18
4.1 BASIS FOR SUBCATEGORIZATION 18
4.1.1 Factors Considered 18
4.1.2 General Conclusions 21
4.2 SECONDARY SUBCATEGORIZATION 21
4.2.1 Chlor-Alkali 21
4.2.2 Titanium Dioxide 22
4.2.3 Hydrogen Cyanide 23
111
-------
TABLE OF CONTENTS (continued)
4.3 INTEGRATION OF SUBCATEGORIES 23
4.3.1 Hydrofluoric Acid and Aluminum 23
Fluoride
4.4 SUMMARY 24
5.0 SCREENING AND VERIFICATION SAMPLING PROGRAMS 25
5.1 SCOPE AND METHODOLOGY 25
5.1.1 Selecting Plants and Making 26
Preliminary Contacts
5.1.2 Screening and Verification Sampling 27
5.1.3 Analytical Methodology for Priority 28
Pollutants
5.1.4 Quality Assurance Provisions 35
5.2 THE BASIS FOR VERIFICATION SAMPLING 36
5.3 THE VERIFICATION PROGRAM 37
6.0 PROCESS AND WASTE TREATMENT INFORMATION DEVELOPMENT 38
AND EVALUATION
6.1 INDUSTRY DATA BASE DESCRIPTION 38
6.1.1 Data Acquisition 38
6.2 PROCESS WASTE SOURCES AND CURRENT TREATMENT 41
PRACTICES
6.2.1 Data Acquisition 41
6.2.2 Evaluation of Data 41
6.2.3 Model Plant and BPT Treatment System 42
Specification
6.2.4 Dissolved Solids in Waste Water 43
Effluents
7.0 TREATMENT AND CONTROL ALTERNATIVES FOR ADVANCED 44
LEVEL APPLICATIONS
7.1 TREATMENT TECHNOLOGY ASSESSMENT 44
7.1.1 Introduction 44
7.1.2 Hydroxide Precipitation 45
7.1.3 Ferrite Co-precipitation 50
7.1.4 Sulfide Precipitation 50
7.1.5 The Xanthate Process 52
7.1.6 -Ion Exchange 54
7.1.7 Reduction Processes 55
7.1.8 Oxidation Processes 57
IV
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TABLE OF CONTENTS (continued)
7.1.9 Membrane Processes 59
7.1.10 Adsorption 62
7.1.11 Fluoride Removal 64
8.0 TREATABILITY ESTIMATES AND LONG TERM DATA ANALYSIS 66
8.1 THE DEVELOPMENT OF TREATABILITY ESTIMATES 66
8.2 THE USE OF HISTORICAL POLLUTANT DATA 80
8.2.1 Determination of Enforcement Guide- 80
lines Based Upon Historical
Performance
8.2.2 Assumptions Concerning 30-Day Average 81
Pollutant Level Measurements
8.2.3 Variability Factor for Daily Samples 81
8.2.4 Variability Factor for 30-Day Averages 82
9.0 TREATMENT TECHNOLOGY APPLICATIONS FOR PRIORITY 84
POLLUTANT REMOVAL
9.1 SELECTION OF POLLUTANTS TO BE CONTROLLED 84
9.2 APPLICATION OF ADVANCED LEVEL TREATMENT AND 84
CONTROL ALTERNATIVES
9.2.1 General Design Objectives 84
9.2.2 Pretreatment Technology 87
9.2.3 New Source Performance Standards 87
9.3 ESTIMATED ACHIEVABLE PERFORMANCE CHARAC- 87
TERISTICS FOR ADVANCED LEVEL APPLICATIONS
9.3.1 Advanced Level Removal of BPT 88
Pollutants
9.3.2 Advanced Level Removal of Priority 88
Pollutants
10.0 COSTS OF TREATMENT AND CONTROL SYSTEMS 89
10.1 INTRODUCTION 89
10.1.1 Purpose of Cost Data 89
10.1.2 General Approach 90
10.1.3 Cost References and Rationale 90
10.1.4 Definition of Levels of Treatment 91
and Control Cost Development
10.1.5 Treatment and Disposal Rationale 91
Applied to Cost Development
10.1.6 Expression of Costs 92
10.2 COST ESTIMATES FOR EACH SUBCATEGORY 99
v
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TABLE OF CONTENTS (continued)
Page
11.0 CHLOR-ALKALI INDUSTRY 10°
11.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL -
MERCURY CELL 10°
11.1.1 Industry Profile and Analytical 100
Results
11.1.2 Process Waste Sources and Waste Water 100
Treatment Data
11.2 TECHNOLOGY BASED POLLUTION ABATEMENT 127
11.2.1 Advanced Level Treatment 127
Applications
11.2.2 Estimated Performance of BPT Systems 131
11.2.3 Estimated Performance of Advanced 135
Level Systems
11.2.4 Cost Estimates 138
11.3 ASSESSMENT OF THE WATER POLLUTION POTENTIAL - 145
DIAPHRAGM CELL
11.3.1 Industry Profile and Analytical 145
Results
11.3.2 Process Waste Sources 154
11.4 TECHNOLOGY BASED POLLUTION ABATEMENT 174
11.4.1 Advanced Level Treatment Applications 174
11.4.2 Estimated Performance of BPT Systems 179
11.4.3 Estimated Performance of Advanced 181
Level Systems
11.4.4 Cost Estimates 184
12.0 HYDROFLUORIC ACID INDUSTRY 194
12.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 194
12.1.1 Industry Profile and Analytical 194
Results
12.1.2 Process Waste Sources and Waste Water 197
Treatment Data
12.2 TECHNOLOGY BASED POLLUTION ABATEMENT 219
12.2.1 Advanced Level Treatment Applications 219
12.2.2 Estimated Performance of BPT Systems 226
12.2.3 Estimated Performance of Advanced 233
Level Systems
12.2.4 Cost Estimates 237
13.0 HYDROGEN PEROXIDE INDUSTRY 253
13.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 253
13.1.1 Industry Profile and Analytical 253
Results
vi
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TABLE OF CONTENTS (continued)
Page
14.0 TITANIUM DIOXIDE INDUSTRY 256
14.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 256
OF THE CHLORIDE PROCESS
14.1.1 Industry Profile and Analytical 256
Results
14.1.2 Process Waste Sources and Waste 259
Water Treatment Data
14.2 TECHNOLOGY BASED POLLUTION ABATEMENT 275
14.2.1 Advanced Level Treatment 275
Applications
14.2.2 Base Level Performance Character- 280
istics for BPT Pollutant Removal
14.2.3 Estimated Performance of Advanced 283
Level Systems
14.2.4 Cost Estimates - Chloride Process 286
14.3 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 293
OF THE SULFATE PROCESS
14.3.1 Industry Profile and Analytical 293
Results
14.3.2 Process Waste Sources and Waste 296
Treatment Data
14.4 TECHNOLOGY BASED POLLUTION ABATEMENT 310
14.4.1 Advanced Level Treatment 310
Application
14.4.2 Base Level Performance Character- 311
istics for BPT Pollutant Removal
14.4.3 Estimated Performance for 318
Advanced Level System
14.4.4 Cost Estimates - Sulfate Process 321
15.0 ALUMINUM FLUORIDE INDUSTRY 328
15.1 ASSESSMENT OF THE WATER POLLUTION
POTENTIAL 328
15.1.1 Industrial Profile and Analytical 328
Results
15.1.2 Process Waste Sources and Waste 333
Water Treatment Data
15.2 TECHNOLOGY BASED POLLUTION ABATEMENT 347
15.2.1 Advanced Level Treatment 347
Applications
15.2.2 Estimated Performance of BPT 353
Systems
vii
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TABLE OF CONTENTS (continued)
Page
15.2.3 Estimated Performance of Advanced 355
Level Systems
15.2.4 Cost Estimates 359
16.0 CHROME PIGMENTS INDUSTRY 376
16.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 376
16.1.1 Industry Profile and Analytical 376
Results
16.1.2 Process Waste Sources and Waste 380
Water Treatment Data
16.2 TECHNOLOGY BASED POLLUTION ABATEMENT 400
16.2.1 Advanced Level Treatment 400
Applications
16.2.2 Estimated Performance of BPT Systems 403
16.2.3 Estimated Performance of Advanced 407
Level Systems
16.2.4 Cost Estimates 407
17.0 HYDROGEN CYANIDE INDUSTRY 417
17.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 417
OF THE ANDRUSSOW PROCESS
17.1.1 Industry Profile and Analytical 417
Results
17.1.2 Process Waste Sources and Waste 422
Water Treatment Data
17.2 TECHNOLOGY BASED POLLUTION ABATEMENT 434
17.2.1 Advanced Level Treatment 434
Applications
17.2.2 Estimated Performance of BPT Systems 435
17.2.3 Estimated Performance of Advanced 444
Level Systems
17.2.4 Cost Estimates 447
18.0 SODIUM DICHROMATE INDUSTRY 454
18.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 454
18.1.1 Industry Profile and Analytical 454
Results
18.1.2 Process Waste Sources and Waste 459
Water Treatment Data
18.2 TECHNOLOGY BASED POLLUTION ABATEMENT 470
18.2.1 Advanced Level Treatment 470
Applications
viii
-------
TABLE OF CONTENTS (continued)
Page
18.2.2 Estimated Performance of BPT Systems 474
18.2.3 Estimated Performance of Advanced 478
Level Systems
18.2.4 Cost Estimates 478
19.0 CARBON DIOXIDE INDUSTRY 487
19.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 487
19.1.1 Industry Profile and Analytical 487
Results
20.0 CARBON MONOXIDE AND BY-PRODUCT HYDROGEN 490
INDUSTRY
20.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 490
20.1.1 Industry Profile and Analytical 490
Results
21.0 COPPER SULFATE INDUSTRY 493
21.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 493
21.1.1 Industry Profile and Analytical 493
Results
21.1.2 Process Waste Sources and Waste 497
Water Treatment Data
21.2 TECHNOLOGY BASED POLLUTION ABATEMENT 503
21.2.1 Advanced Level Treatment 503
Applications
21.2.2 Estimated Performance of BPT Systems 507
21.2.3 Estimated Performance of Advanced 509
Level Systems
21.2.4 Cost Estimates 512
22.0 NICKEL SULFATE INDUSTRY 515
22.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 515
22.1.1 Industry Profile and Analytical 515
Data
22.1.2 Process Waste Sources and Waste 520
Water Treatment Data
22.2 TECHNOLOGY BASED POLLUTION ABATEMENT 529
22.2.1 Advanced Treatment Applications 529
22.2.2 Estimated Performance of BPT Systems 533
ix
-------
TABLE OF CONTENTS (continued)
>age
22.2.3 Estimated Performance of Advanced 533
Level Systems
22.2.4 Cost Estimates 536
23.0 SILVER NITRATE INDUSTRY 544
23.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 544
23.1.1 Industry Profile and Analytical 544
Results
24.0 SODIUM BISULFITE INDUSTRY 547
24.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 547
24.1.1 Industry Profile and Analytical 547
Results
24.1.2 Process Waste Sources and Waste 552
Water Treatment Data
24.2 TECHNOLOGY BASED POLLUTION ABATEMENT 560
24.2.1 Advanced Level Treatment 560
Applications
24.2.2 Estimated Performance of BPT 565
Systems
24.2.3 Estimated Performance of Advanced 567
Level Systems
24.2.4 Cost Estimates 571
25.0 SODIUM HYDROSULFITE 578
25.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 578
25.1.1 Industry Profile and Analytical 578
Results
25.1.2 Process Waste Sources and Waste 581
Water Treatment Data
25.2 TECHNOLOGY BASED POLLUTION ABATEMENT 590
25.2.1 Advanced Level Treatment 590
Applications
25.2.2 Estimated Performance of BPT Systems 595
25.2.3 Estimated Performance of Advanced 598
Level Systems
25.2.4 Cost Estimates 598
26.0 HYDROCHLORIC ACID INDUSTRY 602
26.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 602
26.1.1 Industry Profile and Analytical 602
Results
x
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TABLE OF CONTENTS (continued)
Page
27.0 NITRIC ACID INDUSTRY 605
27.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 605
27.1.1 Industry Profile and Analytical 605
Results
28.0 SODIUM CARBONATE INDUSTRY (SOLVAY PROCESS) 608
28.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 608
28.1.1 Industry Profile and Analytical 608
Results
29.0 SODIUM METAL INDUSTRY 611
29.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 611
29.1.1 Industry Profile and Analytical 611
Results
30.0 SODIUM SILICATE INDUSTRY 614
30.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 614
30.1.1 Industry Profile and Analytical 614
Results
31.0 SULFURIC ACID INDUSTRY 617
31.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 617
31.1.1 Industry Profile and Analytical 617
Results
32.0 AMMONIUM CHLORIDE INDUSTRY 620
32.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 620
32.1.1 Industry Profile and Analytical 620
Results
33.0 AMMONIUM HYDROXIDE INDUSTRY 623
33.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 623
33.1.1 Industry Profile and Analytical 623
Results
XI
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TABLE OF CONTENTS (continued)
Page
34.0 BARIUM CARBONATE INDUSTRY 626
34.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 626
34.1.1 Industry Profile and Analytical 626
Results
35.0 BORIC ACID INDUSTRY 629
35.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 629
35.1.1 Industry Profile and Analytical 629
Results
36.0 CALCIUM CARBONATE INDUSTRY 632
36.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 632
36.1.1 Industry Profile and Analytical 632
Results
37.0 CUPROUS OXIDE INDUSTRY 635
37.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 635
37.1.1 Industry Profile and Analytical 635
Results
38.0 MANGANESE SULFATE INDUSTRY 638
38.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 638
38.1.1 Industry Profile and Analytical 638
Results
39.0 STRONG NITRIC ACID INDUSTRY 641
39.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 641
39.1.1 Industry Profile and Analytical 641
Results
40.0 OXYGEN AND NITROGEN INDUSTRY 644
40.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 644
40.1.1 Industry Profile and Analytical 644
Results
Xll
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TABLE OF CONTENTS (continued)
Page
41.0 POTASSIUM IODIDE INDUSTRY 647
41.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 647
41.1.1 Industry Profile and Analytical 647
Results
42.0 SODIUM HYDROSULFIDE INDUSTRY 650
42.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 650
42.1.1 Industry Profile and Analytical 650
Results
43.0 SODIUM SILICOFLUORIDE INDUSTRY 653
43.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 653
43.1.1 Industry Profile and Analytical 653
Results
44.0 SODIUM THIOSULFATE INDUSTRY 656
44.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 656
44.1.1 Industry Profile and Analytical 656
Results
45.0 SULFUR DIOXIDE INDUSTRY 659
45.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL 659
45.1.1 Industry Profile and Analytical 659
Results
REFERENCES 662
BIBLIOGRAPHY 667
ACKNOWLEDGEMENTS 671
APPENDIX A A-l
XI11
-------
LIST OF FIGURES
Page
5-1 Sample flow sheet for metals 30
7-1 Solubility of metal hydroxides and sulfides 47
7-2 Electrodialysis process 61
11-1 General process diagram for production of chlorine/ 108
caustic by mercury cells
11-2 General process flow diagram at Plant #299 showing 112
the sampling points. Chlorine/Caustic (Mercury
Cell) Manufacture
11-3 General process flow diagram at Plant #747 showing 115
the sampling points. Chlorine/Caustic (Mercury
Cell) Manufacture
11-4 General process flow diagram at Plant #167 showing 117
the sampling points. Chlorine/Caustic (Mercury
Cell) Manufacture
11-5 General process flow diagram at Plant #317 showing 118
the sampling points. Chlorine/Caustic (Mercury
Cell) Manufacture
11-6 Waste water treatment Level 1 for chlorine- 129
mercury cell subcategory
11-7 Waste water treatment Level 2 for chlorine- 130
mercury cell subcategory
11-8 Annual treatment cost vs. production for the 142
Chlorine Subcategory (Mercury Cell Process)
11-9 Annual unit treatment cost vs. production for the 143
Chlorine Subcategory (Mercury Cell Process)
11-10 General process flow diagram for production of' 156
chlorine/caustic by diaphragm cells
11-11 General process flow diagram at Plant #001 showing 159
the sampling points. Chlorine/Caustic (Diaphragm
Cell) Manufacture
11-12 General process flow diagram at Plant #261 showing 162
the sampling points. Chlorine/Caustic (Diaphragm
Cell) Manufacture
xiv
-------
LIST OF FIGURES (continued)
11-13 General process flowsheet at Plant #738 showing 164
the sampling points. Chlorine/Caustic
(Diaphragm Cell) Manufacture
11-14 General process flow diagram at Plant #738 showing 165
the sampling points. Chlorine/Caustic
(Diaphragm Cell) Manufacture
11-15 General process flow diagram at Plant #967 showing 167
the sampling points. Chlorine/Caustic
(Diaphragm Cell) Manufacture
11-16 General process flow diagram at Plant #736 showing 168
the sampling points. Chlorine/Caustic
(Diaphragm Cell) Manufacture
11-17 Waste water treatment Level 1 for chlorine - 176
diaphragm cell subcategory
11-18 Waste water treatment Level 2 for chlorine- 177
diaphragm cell subcategory
11-19 Waste water treatment Level 3 for chlorine - 178
diaphragm cell subcategory
11-20 Annual treatment cost vs. production for the 190
Chlorine Subcategory (Diaphragm Cell Process)
11-21 Annual unit treatment cost vs. production for the 191
Chlorine Subcategory (Diaphragm Cell Process)
12-1 General process flow diagram for production of 202
hydrofluoric acid
12-2 General process flow diagram at Plant #705 showing 208
the sampling points. Hydrofluoric Acid Manufacture
12-3 General process flow diagram at Plant #251 showing 211
the sampling points. Hydrofluoric Acid Manufacture
12-4 Production versus waste flow data for HF plants 213
12-5 Waste water treatment Level 1 for hydrofluoric 221
acid subcategory
12-6 Waste water treatment Level 2 for hydrofluoric 222
acid subcategory
12-7 Waste water treatment Level 3 for hydrofluoric 223
acid subcategory
-------
LIST OF FIGURES (continued)
Page
12-8 Waste water treatment Level 4 for hydrofluoric 224
acid subcategory
12-9 Waste water treatment new source performance 225
standard for hydrofluoric acid subcategory
12-10 Annual treatment cost vs. production for the 242
Hydrofluoric Acid Subcategory
12-11 Annual unit treatment cost vs. production for the 243
Hydrofluoric Acid Subcategory
12-12 Annual treatment cost vs. production for the 250
Hydrofluoric Acid Subcategory (NSPS)
12-13 Annual unit treatment cost vs. production for the 251
Hydrofluoric Acid Subcategory (NSPS)
14-1 General process diagram for production of titanium 264
dioxide (chloride process)
14-2 General flow diagram at Plant #559 showing the 267
sampling points. Titanium Dioxide (Chloride
Process) Manufacture
14-3 General flow diagram at Plant #172 showing the 270
sampling points. Titanium Dioxide (Chloride
Process) Manufacture
14-4 Waste water treatment Level 1 for titanium dioxide - 277
chloride process
14-5 Waste water treatment Level 2 for titanium dioxide - 278
chloride process
14-6 Waste water treatment Level 3 for titanium dioxide - 279
chloride process
14-7 Annual treatment cost vs. production for the 290
Titanium Dioxide Subcategory, Chloride Process
14-8 Annual unit treatment cost vs. production for the 291
Titanium Dioxide Subcategory, Chloride Process
14-9 General process flow diagram for production of 299
Titanium Dioxide by sulfate process
14-10 General flow diagram at Plant #559 showing the 303
sampling points. Titanium Dioxide (Sulfate Process)
xv i
-------
LIST OF FIGURES (continued)
14-lte water treatment Level 1 for titanium dioxide - 312
fate process
14-lte water treatment Level 2 for titanium dioxide - 313
fate process
14-lual treatment cost vs. production for the 325
anium Dioxide Subcategory, Sulfate Process
14-Jual unit treatment cost vs. production for the 326
anium Dioxide Subcategory, Sulfate Process
15-Jeral process flow diagram for production of 334
minum fluoride
15-2eral process flow diagram at Plant #705 showing 339
sampling points. (Aluminum Fluoride Manufacture)
15-^eral process flow diagram at Plant #605 showing 341
sampling points. Aluminum Fluoride Manufacture
15-^duction vs. Unit Waste Flow for Aluminum 343
oride Manufacture
15-fte water treatment Level 1 for aluminum fluoride 349
-category
15-(te water treatment Level 2 for aluminum fluoride 350
>category
15-ite water treatment Level 3 for aluminum fluoride 351
>category
15-;te water treatment Level 4 for aluminum fluoride 352
>category
15-mal treatment cost vs. production for the 363
uninum Fluoride Subcategory
15-iual unit treatment cost vs. production for the 364
iminum Fluoride Subcategory
15-cect of variation of pollutant load on treatment 367
3t at level 1 technology
15-Eect of variation of pollutant load on treatment 368
st at level 4 technology
xvi i
-------
LIST OF FIGURES (continued)
Page
15-13 Effect of variation of hydraulic load on treatment 371
cost at level 2 technology
15-14 Effect of variation of hydraulic load on treatment 372
cost at level 3 technology
•
15-15 Effect of variation of hydraulic load on treatment 373
cost at level 4 technology
16-1 General process diagram for production of anhydrous 383
chrome oxide
16-2 General process diagram for production of hydrated 384
chromic oxide
16-3 General process diagram for production of chrome 385
yellow
16-4 General process diagram for production of molybdate 387
orange
16-5 General process diagram for production of chrome 388
green
16-6 General process diagram for production of zinc 390
yellow
16-7 General process diagram for production of chrome 392
pigment complexes
16-8 General waste water treatment process flow diagram 395
at Plant #894 showing the sampling points. (Chrome
Pigment Manufacture)
16-9 General waste water treatment process flow diagram 397
at Plant #002 showing the sampling points. (Chrome
Pigment Manufacture)
16-10 Waste water treatment Level 1 for chrome pigments 401
16-11 Waste water treatment Level 2 for chrome pigments 402
16-12 Annual treatment cost vs. production for the Chrome 414
Pigments Subcategory
16-13 Annual unit treatment cost vs. production for the 415
Chrome Pigments Subcategory
xvi 11
-------
LIST OF FIGURES (continued)
Page
17-1 General process flow diagram for production of 424
hydrogen cyanide by the Andrussow Process
17-2 General waste water treatment process flow diagram 427
at Plant #765 showing the sampling points. (Hydrogen
Cyanide Manufacture)
17-3 General waste water treatment process flow diagram 430
at Plant #782 showing the sampling points.
(Hydrogen Cyanide Manufacture)
17-4 Waste water treatment Level 1 for hydrogen cyanide 436
subcategory
17-5 Waste water treatment Level 2 for hydrogen cyanide 437
subcategory
17-6 Annual treatment cost as a function of production for 451
the Hydrogen Cyanide Subcategory
17-7 Annual unit treatment cost as a function of produc- 452
tion for the Hydrogen Cyanide Subcategory
18-1 General process diagram for production of sodium 461
dichromate
18-2 General waste water treatment process flow diagram 464
at Plant #493 showing the sampling points.
(Sodium Dichromate Manufacture)
18-3 General waste water treatment process flow diagram 466
at Plant #376 showing the sampling points. (Sodium
Dichromate Manufacture)
18-4 Waste water treatment Level 1 for sodium dichromate 472
subcategory
18-5 Waste water treatment Level 2 for sodium dichromate 473
subcategory
18-6 Relationship of annual treatment cost to production 483
for the Sodium Dichromate Subcategory
18-7 Relationship of annual unit treatment cost to 484
production for the Sodium Dichromate Subcategory
21-1 General process flow diagram at Plant #034 showing 501
the sampling points. Copper Sulfate Manufacture
xix
-------
LIST OF FIGURES (continued)
21-2 Waste water treatment Level 1 for copper sulfate 505
subcategory - batch process
21-3 Waste water treatment Level 2 for copper sulfate 506
subcategory - batch process
22-1 General waste water treatment process flow diagram 523
showing the sampling points. (Nickel Sulfate
Manufacture)
22-2 General process flow diagram at Plant #572 showing 525
the sampling points. Nickel Sulfate Manufacture
22-3 General process flow diagram of Plant #120. Nickel 526
Sulfate Manufacture
22-4 General waste water treatment process flow diagram 527
at Plant #120 showing the sampling points. (Nickel
Sulfate Manufacture)
22-5 Waste water treatment Level 1 for nickel sulfate 531
subcategory - batch process
22-6 Waste water treatment Level 2 for nickel sulfate 532
subcategory - batch process
22-7 Relationship of annual treatment cost to production 541
for the Nickel Sulfate Subcategory
22-8 Relationship of annual unit treatment cost to 542
production for the Nickel Sulfate Subcategory
24-1 General process flow diagram at Plant #282 showing 556
the sampling points. Sodium Bisulfite Manufacture
24-2 General flow diagram at Plant #586 showing the 557
sampling points. Sodium Bisulfite Manufacture
24-3 General process flow diagram at Plant #987 showing 559
the sampling points. Sodium Bisulfite Manufacture
24-4 Waste water treatment Level 1 for sodium bisulfite 562
subcategory - batch process
24-5 Waste water treatment Level 2 for sodium bisulfite 563
subcategory - batch process
-------
LIST OF FIGURES (continued)
Page
24-6 Waste water treatment Level 3 for sodium bisulfite 564
subcategory
24-7 Variation of annual treatment cost with production 575
for the Sodium Bisulfite Subcategory
24-8 Variation of annual unit treatment cost with 576
production (Sodium Bisulfite Subcategory)
25-1 General process flow diagram at Plant #672 584
Sodium Hydrosulfite Manufacture
25-2 General process flow diagram at Plant #771 showing 586
the sampling points. Sodium Hydrosulfite
Manufacture
25-3 Waste water treatment level 1 for sodium 593
hydrosulfite
25-4 Waste water treatment Level 2 for sodium 594
hydrosulfite
-------
LIST OF TABLES
Page
3-1 Recoinmended List of Priority Pollutants 8
5-1 Analytical Detection Limits for Metals 33
7-1 Solubility Products of Trace Metals 48
7-2 Comparison of Reverse Osmosis Concepts 63
8-1 Waste Water Treatment Options and Performance 67
Data Summary - Antimony and Arsenic Removal
8-2 Waste Water Treatment Options and Performance 68
Data Summary - Beryllium and Cadmium Removal
8-3 Waste Water Treatment Options and Performance 69
Data Summary - Copper Removal
8-4 Waste Water Treatment Options and Performance 70
Data Summary - Chromium III and Chromium VI
Removal
8-5 Waste Water Treatment Options and Performance 71
Data Summary - Lead Removal
8-6 Waste Water Treatment Options and Performance 72
Data Summary - Mercury II Removal
8-7 Waste Water Treatment Options and Performance 73
Data Summary - Nickel Removal
8-8 Waste Water Treatment Options and Performance 74
Data Summary - Silver Removal
8-9 Waste Water Treatment Options and Performance 75
Data Summary - Selenium and Thallium Removal
8-10 Waste Water Treatment Options and Performance 76
Data Summary - Zinc Removal
8-11 Estimated Achievable 30-Day Averages for the Applied 78
Technologies
9-1 Prioritization of Pollutant Metals Found in Each 85
Subcategory
11-1 Subcategory Profile Data Summary - Chlorine Mercury 101
Cell
11-2 Existing Regulations - Effluent Limitation 102
Guidelines
xxii
-------
LIST OF TABLES (continued)
11-3 Summary of Raw Waste Loadings Found in Screening 104
and Verification Sampling
11-4 Priority Pollutant Raw Waste Loads (in kg/kkg of 105
Product)
11-5 Tail Gas Scrubber Flow Data for Chlorine/Caustic 110
Subcategory
11-6 Flow and Pollutant Concentration Data of the Sampled 113
Waste Streams for Plant #299 Producing Chlorine by
Mercury Cells
11-7 Flow and Pollutant Concentration Data of the Sampled 116
Waste Streams for Plants #747, #167 and #317
Producing Chlorine by Mercury Cells
11-8 Waste Flow Data for Chlorine/Caustic Subcategory 124
Using Mercury Cells
11-9 Residual Chlorine Effluent Loadings at Selected 132
CHlor-Alkali Plants
11-10 Effluent Loadings from Selected Chlor-Alkali Mercury 133
Cell Plants
11-11 Effluent Priority Pollutant Loads following Mercury 134
Treatment
11-12 Control Parameter Limitations 136
Subcategory: Chlorine - Mercury Cell
11-13 Control Parameter Limitations 137
Subcategory: Chlorine - Mercury Cell
11-14 Model Plant Treatment Costs 139
Subcategory: Chlorine Mercury Cell
11-15 Model Plant Treatment Costs 140
Subcategory: Chlorine Mercury Cell
11-16 Model Plant Treatment Costs 141
Subcategory: Chlorine Mercury Cell
11-17 Model Plant Treatment Costs 144
Subcategory: Chlorine Mercury Cell
11-18 Subcategory Profile Data Summary 146
Subcategory: Chlorine Diaphragm Cell
xxiii
-------
LIST OF TABLES (continued)
Page
11-19 Summary of Raw Waste Loadings Found in Screening 148
and Verification Sampling
11-20 Priority Pollutant Raw Waste Loads 149
11-20A Results of Asbestos Sampling at Diaphragm Cell 150
Plants
11-21 Metal Priority Pollutant Raw Waste Loadings Found 152
in Sampling at a Chlorine-Diaphragm Cell Plant with
Graphite Anodes
11-22 Organic Priority Pollutant Raw Waste Loadings Found 153
in Sampling at a Chlorine - Diaphragm Cell Plant
with Graphite Anode
11-23 Data of Water Usage for Barometric Condenser in 157
Chlorine/Caustic Plants Using Diaphragm Cells
11-24 Flow and Pollutant Concentration Data of the Sampled 160
Waste Streams for Plants #277, #261, and #738
Producing Chlorine/Caustic by Diaphragm Cells
11-25 Flow and Pollutant Concentration Data of the Sampled 166
Waste Streams for Plants #967 and #736 Producing
Chlorine by Diaphragm Cell
11-26 Waste Flow Data for Chlorine/Caustic Subcategory 172
Using Diaphragm Cells
11-27 Effluent Loadings from Selected Chlor-Alkali 180
Diaphragm Cell Plants
11-28 Priority Pollutant Removal at Lead Treatment 182
Facility Plant #967
11-29 Control Parameter Limitations 183
Subcategory: Chlorine - Diaphragm Cell
11-30 Control Parameter Limitations 185
Subcategory: Chlorine - Diaphragm Cell
11-31 Control Parameter Limitations 186
Subcategory: Chlorine - Diaphragm Cell
11-32 Model Plant Treatment Costs 187
Subcategory: Chlorine Diaphragm Cell
11-33 Model Plant Treatment Costs 188
Subcategory: Chlorine Diaphragm Cell
xxiv
-------
LIST OF TABLES (continued)
Page
11-34 Model Plant Treatment Costs 189
Subcategory: Chlorine Diaphragm Cell
11-35 Model Plant Treatment Costs 192
Subcategory: Chlorine Diaphragm Cell
12-1 Subcategory Profile Data Summary J-95
Subcategory: Hydrofluoric Acid
12-2 Existing Regulations - Effluent Limitation 196
Guidelines
12-3 Summary of Raw Waste Loadings Found in Screening 198
and Verification Sampling
12-4 Priority Pollutant Raw Waste Loads 199
12-5 Water Usage in the Hydrofluoric Acid Subcategory 203
12-6 Waste Flow from Hydrofluoric Acid Manufacturing 205
Plants, m^/kkg of Hydrofluoric Acid
12-7 Flow and Pollutant Concentration Data of the Sampled 209
Waste Streams of Plant #705 Producing Hydrofluoric
Acid
12-8 Flow and Pollutant Concentration Data of the Sampled 210
Waste Streams for Plants #705 and #251 Producing
Hydrofluoric Acid
12-9 Waste Water Influent Data to Treatment Facility 212
in the Hydrofluoric Acid Subcategory
12-10 Summary of Solid Waste Generated from the HF 215
Manufacturing Processes and Treatment Facilities
at Plants #705 and #251
12-11 Gypsum Solids Production in the Hydrofluoric Acid 216
Subcategory
12-12 Summary of Waste Water Control and Treatment 227
Technology Employed at Hydrofluoric Acid Plants
12-13 Summary of Effluent Quality Attained and Variability 230
Observed at Four Representative Hydrofluoric Acid
Plants
xxv
-------
LIST OF TABLES (continued)
Paqe
12-14 Control Parameter Limitations 231
Subcategory: Hydrofluoric Acid
12-15 Priority Pollutant Removal at Hydrofluoric Acid 232
Plants
12-16 Control Parameter Limitations 234
Subcategory: Hydrofluoric Acid
12-17 Control Parameter Limitations 235
Subcategory: Hydrofluoric Acid
12-18 Control Parameter Limitations 236
Subcategory: Hydrofluoric Acid
12-19 Control Parameter Limitations 238
Subcategory: Hydrofluoric Acid
12-20 Model Plant Treatment Costs 239
Subcategory: Hydrofluoric Acid
12-21 Model Plant Treatment Costs 240
Subcategory: Hydrofluoric Acid
12-22 Model Plant Treatment Costs 241
Subcategory: Hydrofluoric Acid
12-23 Model Plant Treatment Costs 245
Subcategory: Hydrofluoric Acid
12-24 Model Plant Treatment Costs 246
Subcategory: Hydrofluoric Acid
12-25 Model Plant Treatment Costs 247
Subcategory: Hydrofluoric Acid
12-26 Model Plant Treatment Costs 248
Subcategory: Hydrofluoric Acid
12-27 Model Plant Treatment Costs 252
Subcategory: Hydrofluoric Acid
13-1 Subcategory Profile Data Summary 254
Subcategory: Hydrogen Peroxide
13-2 Existing Regulations - Effluent Limitation 255
Guidelines
xxvi
-------
LIST OF TABLES (continued)
Page
14-1 Subcategory Profile Data Summary 257
Subcategory: Titanium Dioxide Chloride Process
14-2 Existing Regulations - Effluent Limitation 258
Guidelines
14-3 Summary of Raw Waste Loadings Found in Screening 260
and Verification Sampling
14-4 Priority Pollutant Raw Waste Loads 261
14-5 Water Usage in Titanium Dioxide - Chloride Process 265
Subcategory
14-6 Flow and Pollutant Concentration Data of the Sampled 268
Waste Streams for Plant #559 Producing Titanium
Dioxide (Chloride Process)
14-7 Flow and Pollutant Concentration Data of the Sampled 271
Waste Streams for Plant #172 Producing Titanium
Dioxide (Chloride Process)
14-8 Solid Waste Produced in Titanium Dioxide - Chloride 273
Process Subcategory
14-9 Waste Water Flow for Titanium Dioxide - Chloride 273
Process Subcategory
14-10 Raw Waste and Treated Effluent Quality at Titanium 231
Dioxide - Chloride Process Plants
14-11 Control Parameter Limitations 282
Subcategory: Titanium Dioxide - Chloride Process
14-12 Control Parameter Limitations 284
Subcategory: Titanium Dioxide - Chloride Process
14-13 Control Parameter Limitations 285
Subcategory: Titanium Dioxide - Chloride Process
14-14 Model Plant Treatment Costs 287
Subcategory: Titanium Dioxide - Chloride
14-15 Model Plant Treatment Costs 288
Subcategory: Titanium Dioxide - Chloride
14-16 Model Plant Treatment Costs 289
Subcategory: Titanium Dioxide - Chloride
xxv ii
-------
LIST OF TABLES (continued)
>aqe
14-17 Model Plant Treatment Costs 292
Subcategory: Titanium Dioxide - Chloride
14-18 Subcategory Profile Data Summary 293A
Subcategory: Titanium Dioxide Sulfate Process
14-19 Summary of Raw Waste Loadings Found in Screening 294
and Verification Sampling
14-20 Priority Pollutant Raw Waste Loads 295
14-21 Analysis of Ilmenite Ores 297
14-22 Water Usage in Titanium Dioxide - Sulfate Process 300
Subcategory
14-23 Flow and Pollutant Concentration Data of the Waste 304
Streams Sampled for Plant #559 Producing Titanium
Dioxide (Sulfate Process)
14-24 Effluent Flow at Plants #555, #605 and #559 306
Producing Titanium Dioxide (Sulfate Process)
14-25 Raw Waste Characteristics (Industry Data) for Plant 307
#555 (Production of TiO. by Sulfate Process)
14-26 Summary of Existing Control and Treatment Technology 315
for Sulfate-Process Titanium Dioxide Plants
14-27 . Summary of Daily Effluent Monitoring Data for 316
Combined Waste Water Treatment Discharge at Sulfate-
Process Titanium Dioxide Plant #559
14-28 Verification Results Titanium Dioxide Plant #559 317
14-29 Control Parameter Limitations 319
Subcategory: Titanium Dioxide - Sulfate Process
14-30 Control Parameter Limitations 320
Subcategory: Titanium Dioxide - Sulfate Process
14-31 Model Plant Treatment Costs 322
Subcategory: Titanium Dioxide Sulfate
14-32 Model Plant Treatment Costs 323
Subcategory: Titanium Dioxide Sulfate
xxvi11
-------
LIST OF TABLES (continued)
Page
14-33 Model Plant Treatment Costs 324
Subcategory: Titanium Dioxide Sulfate
14-34 Model Plant Treatment Costs 327
Subcategory: Titanium Dioxide Sulfate
15-1 Subcategory Profile Data Summary 329
Subcategory: Aluminum Fluoride
15-2 Existing Regulations - Effluent Limitation 330
Guidelines
15-3 Summary of Raw Waste Loadings Found in Screening 331
and Verification Sampling
15-4 Priority Pollutant Raw Waste Loads 332
15-5 Water Usage in the Aluminum Fluoride Subcategory 335
15-6 Waste Water Flow at Plants #837, #705 and #605 337
for Aluminum Fluoride Subcategory
15-7 Flow and Pollutant Concentration Data of the Sampled 340
Waste Streams for Plant #705 Producing Aluminum
Fluoride
15-8 Flow and Pollutant Concentration Data of the Sampled 342
Streams for Plant #605 Producing Aluminum Fluoride
15-9 Solids Generated at Plant #705 and #605 Producing 345
Aluminum Fluoride
15-10 Control Parameter Limitations 354
Subcategory: Aluminum Fluoride
15-11 Control Parameter Limitations 356
Subcategory: Aluminum Fluoride
15-12 Control Parameter Limitations 357
Subcategory: Aluminum Fluoride
15-13 Control Parameter Limitations 358
Subcategory: Aluminum Fluoride
15-14 Model Plant Treatment Costs 360
Subcategory: Aluminum Fluoride
15-15 Model Plant Treatment Costs 361
Subcategory: Aluminum Fluoride
xx ix
-------
LIST OF TABLES (continued)
Page
15-16 Model Plant Treatment Costs 362
Subcategory: Aluminum Fluoride
15-17 Model Plant Treatment Costs 365
Subcategory: Aluminum Fluoride
15-18 Model Plant Treatment Costs 366
Subcategory: Aluminum Fluoride
15-19 Model Plant Treatment Costs 369
Subcategory: Aluminum Fluoride
15-20 Model Plant Treatment Costs 370
Subcategory: Aluminum Fluoride
15-21 Model Plant Treatment Costs 374
Subcategory: Aluminum Fluoride
16-1 Subcategory Profile Data Summary 377
Subcategory: Chrome Pigments
16-2 Existing Regulations - Effluent Limitation 378
Guidelines
16-3 Summary of Raw Waste Loadings Found in Screening 379
and Verification Sampling
16-4 Priority Pollutant Raw Waste Loads 381
16-5 Water Usage in the Chrome Pigments Subcategory 391
16-6 Aqueous Process Waste Effluents in Chrome 393
Pigments Subcategory
16-7 Flow and Pollutant Concentration Data of the Sampled 396
Waste Streams for Plant #894 Producing Chrome
Pigments
16-8 Flow and Pollutant Concentration Data of the Sampled 396
Waste Streams for Plant #002 Producing Chrome
Pigments
16-9 Monitoring and Verification Sampling of Chrome 405
Pigments Plant #894
16-10 Control Parameter Limitations 406
Subcategory: Chrome Pigments
xxx
-------
LIST OF TABLES (continued)
Page
16-11 Control Parameter Limitations 408
Subcategory: Chrome Pigments
16-12 Model Plant Treatment Costs 409
Subcategory: Chrome Pigments
16-13 Model Plant Treatment Costs 410
Subcategory: Chrome Pigments
16-14 Model Plant Treatment Costs 411
Subcategory: Chrome Pigments
16-15 Model Plant Treatment Costs 412
Subcategory: Chrome Pigments
16-16 Model Plant Treatment Costs 416
Subcategory: Chrome Pigments
17-1 Subcategory Profile Data Summary 418
Subcategory: Hydrogen Cyanide
17-2 Existing Regulations - Effluent Limitation 419
Guidelines
17-3 Summary of Raw Waste Loadings Found in Screening 420
and Verification Sampling
17-4 Priority Pollutant Raw Waste Loads 421
17-5 Water Usage in Hydrogen Cyanide - Andrussow 425
Process Subcategory
17-6 Flow and Pollutant Concentration Data of the Sampled 428
Waste Streams for Plant #765 Producing Hydrogen
Cyanide
17-7 Flow and Pollutant Concentration Data of the Sampled 431
Waste Streams for Plant #782 Producing Hydrogen
Cyanide
17-8 Waste Flow Data for HCN Production by the Andrussow 432
Process
17-9 Verification Sampling of Hydrogen Cyanide Plant #782 439
17-10 Verification Sampling of Hydrogen Cyanide Plant #765 440
-------
LIST OF TABLES (continued)
Page
17-11 Control Parameter Limitations 442
Subcategory: Hydrogen Cyanide
17-12 Control Parameter Limitations 443
Subcategory: Hydrogen Cyanide
17-13 Control Parameter Limitations 445
Subcategory: Hydrogen Cyanide
17-14 Control Parameter Limitations 446
Subcategory: Hydrogen Cyanide
17-15 Model Plant Treatment Costs 448
Subcategory: Hydrogen Cyanide
17-16 Model Plant Treatment Costs 449
Subcategory: Hydrogen Cyanide
17-17 Model Plant Treatment Costs 450
Subcategory: Hydrogen Cyanide
17-18 Model Plant Treatment Costs 453
Subcategory: Hydrogen Cyanide
18-1 Subcategory Profile Data Summary 455
Subcategory: Sodium Bichromate
18-2 Existing Regulations - Effluent Limitation 456
Guidelines
18-3 Summary of Raw Waste Loadings Found in Screening 457
and Verification Sampling
18-4 Priority Pollutant Raw Waste Loads 458
18-5 Water Usage in Sodium Bichromate Subcategory 462
18-6 Flow and Pollutant Concentration Bata of the Sampled 465
Waste Streams for Plant #493 Producing Sodium
Bichromate
18-7 Flow and Pollutant Concentration Bata of the Sampled 467
Waste Streams for Plant #376 Producing Sodium
Bichromate
18-8 Flow and Pollutant Concentration Bata of the Sampled 468
Waste Streams for Plant #398 Producing Sodium
Bichromate
xxxii
-------
LIST OF TABLES (continued)
Page
18-9 Effluent Control and Treatment Practices and 475
Achievements at Sodium Bichromate Plants
18-10 Verification Sampling of Sodium Bichromate Plants 476
18-11 Control Parameter Limitations 477
Subcategory: Sodium Bichromate
18-12 Control Parameter Limitations 479
Subcategory: Sodium Bichromate
18-13 Model Plant Treatment Costs 480
Subcategory: Sodium Bichromate
18-14 Model Plant Treatment Costs 481
Subcategory: Sodium Bichromate
18-15 Model Plant Treatment Costs 482
Subcategory: Sodium Bichromate
18-16 Model Plant Treatment Costs 486
Subcategory: Sodium Bichromate
19-1 Subcategory Profile Bata Summary 488
Subcategory: Carbon Bioxide
19-2 Existing Regulations - Effluent Limitation 489
Guidelines
20-1 Subcategory Profile Bata Summary 491
Subcategory: Carbon Monoxide and By-Product
Hydrogen
20-2 Existing Regulations - Effluent Limitation 492
Guidelines
21-1 Subcategory Profile Bata Summary 494
Subcategory: Copper Sulfate
21-2 Existing Regulations - Effluent Limitation 495
Guidelines
21-3 Summary of Raw Waste Loadings Found at Copper 496
Sulfate Plant #034
21-4 Water Usage in Copper Sulfate Subcategory 498
21-5 Flow and Pollutant Concentration Bata of the Sampled 502
Waste Streams for Plant #034 Producing Copper Sulfate
xxxiii
-------
LIST OF TABLES (continued)
Page
21-6 Verification Sampling of Copper Sulfate Plant #034 508
21-7 Control Parameter Limitations 510
Subcategory: Copper Sulfate
21-8 Control Parameter Limitations 511
Subcategory: Copper Sulfate
21-9 Model Plant Treatment Costs 513
Subcategory: Copper Sulfate
21-10 Model Plant Treatment Costs 514
Subcategory: Copper Sulfate
22-1 Subcategory Profile Data Summary 516
Subcategory: Nickel Sulfate
22-2 Existing Regulations - Effluent Limitation 517
Guidelines
22-3 Summary of Raw Waste Loadings Found in Screening 518
and Verification Sampling
22-4 Priority Pollutant Raw Waste Loads 519
22-5 Water Usage in the Nickel Sulfate Subcategory 521
22-6 Flow and Pollutant Concentration Data of the Sampled 524
Waste Streams for Plants Producing Nickel Sulfate
22-7 Waste Characteristics of Nickel Sulfate Plant #120 534
22-8 Control Parameter Limitations 535
Subcategory: Nickel Sulfate
22-9 Control Parameter Limitations 537
Subcategory: Nickel Sulfate
22-10 Model Plant Treatment Costs 538
Subcategory: Nickel Sulfate
22-11 Model Plant Treatment Costs 539
Subcategory: Nickel Sulfate
22-12 Model Plant Treatment Costs 540
Subcategory: Nickel Sulfate
22-13 Model Plant Treatment Costs 543
Subcategory: Nickel Sulfate
xxx iv
-------
LIST OF TABLES (continued)
Page
23-1 Subcategory Profile Data Summary 545
Subcategory: Silver Nitrate
23-2 Existing Regulations - Effluent Limitation 546
Guidelines
24-1 Subcategory Profile Data Summary 548
Subcategory: Sodium Bisulfite
24-2 Existing Regulations - Effluent Limitation 549
Guidelines
24-3 Summary of Raw Waste Loadings Found in Screening 550
and Verification Sampling
24-4 Priority Pollutant Raw Waste Loads 551
24-5 Water Usage in the Sodium Bisulfite Subcategory 553
24-6 Flow and Pollutant Concentration Data of the Sampled 555
Waste Streams for Plant #282 Producing Sodium
Bisulfite
24-7 Flow and Pollutant Concentration Data of the Sampled 555
Waste Streams for Plant #586 Producing Sodium
Bisulfite
24-8 Flow and Pollutant Concentration Data of the Sampled 558
Waste Streams for Plant #987 Producing Sodium
Bisulfite
24-9 Treatment Practices and Verification Sampling at 566
Sodium Bisulfite Plants
24-10 Control Parameter Limitations 568
Subcategory: Sodium Bisulfite
24-11 Control Parameter Limitations 569
Subcategory: Sodium Bisulfite
24-12 Control Parameter Limitations 570
Subcategory: Sodium Bisulfite
24-13 Model Plant Treatment Costs 572
Subcategory: Sodium Bisulfite
24-14 Model Plant Treatment Costs 573
Subcategory: Sodium Bisulfite
xxxv
-------
LIST OF TABLES (continued)
Paqe
24-15 Model Plant Treatment Costs 574
Subcategory: Sodium Bisulfite
24-16 Model Plant Treatment Costs 577
Subcategory: Sodium Bisulfite
25-1 Subcategory Profile Data Summary 579
Subcategory: Sodium Hydrosulfite (Formate Process)
25-2 Existing Regulations - Effluent Limitation 580
Guidelines
25-3 Summary of Raw Waste Loadings Found at a Sodium 582
Hydrosulfite Plant (Formate Process)
25-4 Flow and Pollutant Concentration Data of the Sampled 587
Waste Streams for Plant #672 Producing Sodium
Hydrosulfite
25-5 Influent and Effluent Quality and Efficiency for 589
Plant #672 Waste Water Treatment System Found
During Screening Sampling
25-6 Screening Results from Sodium Hydrosulfite Plant 596
#672
25-7 Control Parameter Limitations 597
Subcategory: Sodium Hydrosulfite
25-8 Control Parameter Limitations 599
Subcategory: Sodium Hydrosulfite
25-9 Model Plant Treatment Costs 600
Subcategory: Sodium Hydrosulfite
25-10 Model Plant Treatment Costs 601
Subcategory: Sodium Hydrosulfite
26-1 Subcategory Profile Data Summary 603
Subcategory: Hydrochloric Acid
26-2 Existing Regulations - Effluent Limitation 604
Guidelines
27-1 Subcategory Profile Data Summary 606
Subcategory: Nitric Acid
27-2 Existing Regulations - Effluent Limitation 607
Guidelines
xxxvi
-------
LIST OF TABLES (continued)
Page
28-1 Subcategory Profile Data Summary 609
Subcategory: Sodium Carbonate
28-2 Existing Regulations - Effluent Limitation ,610
Guidelines
29-1 Subcategory Profile Data Summary 612
Subcategory: Sodium Metal
29-2 Existing Regulations - Effluent Limitation 613
Guidelines
30-1 Subcategory Profile Data Summary 615
Subcategory: Sodium Silicate
30-2 Existing Regulations - Effluent Limitation 616
Guidelines
31-1 Subcategory Profile Data Summary 618
Subcategory: Sulfuric Acid
31-2 Existing Regulations - Effluent Limitation 619
Guidelines
32-1 Subcategory Profile Data Summary 621
Subcategory: Ammonium Chloride
32-2 Existing Regulations - Effluent Limitation 622
Guidelines
33-1 Subcategory Profile Data Summary 624
Subcategory: Ammonium Hydroxide
33-2 Existing Regulations - Effluent Limitation 625
Guidelines
34-1 Subcategory Profile Data Summary 627
Subcategory: Barium Carbonate
34-2 Existing Regulations - Effluent Limitation 628
Guidelines
35-1 Subcategory Profile Data Summary 630
Subcategory: Boric Acid
35-2 Existing Regulations - Effluent Limitation 631
Guidelines
xxxvn
-------
LIST OF TABLES (continued)
Page
36-1 Subcategory Profile Data Summary 633
Subcategory: Calcium Carbonate
36-2 Existing Regulations - Effluent Limitation 634
Guidelines
37-1 Subcategory Profile Data Summary 636
Subcategory: Cuprous Oxide
37-2 Existing Regulations - Effluent Limitation 637
Guidelines
38-1 Subcategory Profile Data Summary 639
Subcategory: Manganese Sulfate
38-2 Existing Regulations - Effluent Limitation 640
Guidelines
39-1 Subcategory Profile Data Summary 642
Subcategory: Strong Nitric Acid
39-2 Existing Regulations - Effluent Limitation 643
Guidelines
40-1 Subcategory Profile Data Summary 645
Subcategory: Oxygen and Nitrogen
40-2 Existing Regulations - Effluent Limitation 646
Guidelines
41-1 Subcategory Profile Data Summary 648
Subcategory: Potassium Iodide
41-2 Existing Regulations - Effluent Limitation 649
Guidelines
42-1 Subcategory Profile Data Summary 651
Subcategory: Sodium Hydrosulfide
42-2 Existing Regulations - Effluent Limitation 652
Guidelines
43-1 Subcategory Profile Data Summary 654
Subcategory: Sodium Silicofluoride
43-2 Existing Regulations - Effluent Limitation 655
Guidelines
XXXVlll
-------
LIST OF TABLES (continued)
Page
44-1 Subcategory Profile Data Summary 657
Subcategory: Sodium Thiosulfate
44-2 Existing Regulations - Effluent Limitation 658
Guidelines
45-1 Subcategory Profile Data Summary 660
Subcategory: Sulfur Dioxide
45-2 Existing Regulations - Effluent Limitation 661
Guidelines
xxx ix
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SECTION 1.0
CONCLUSIONS AND SUMMARY
1.1 PRIORITY POLLUTANTS
This study has shown that certain priority pollutants,
particularly the 13 metals, cyanide and asbestos are present in
significant amounts in process waste waters generated by plants
in 11 of the 35 inorganic chemical product subcategories
screened. Very few of the listed organic priority pollutants
were found in process waste streams and those that were
identified, in most cases, were not present in significant
amounts.
The results of the screening sampling program are given in
support of 24 candidate subcategory exclusions in accordance with
the provisions of Parag'raph 8 of the Settlement Agreement in
Natural Resources Defense Council, et al. v. Train (June 8,
1976). Those screening results which indicated the presence of
priority pollutants in significant amounts were largely confirmed
by the results of the verification program. Verification
sampling accounted for 50 to 75 percent of the current inorganic
chemical production rate in the subcategories'covered.
The sources of most of the priority pollutants found in the
raw wastes and treated effluents can be traced to specific
process related raw materials and chemicals used in the
manufacturing operations. In the case of certain pollutants
found in widely varying amounts or with erratic frequencies of
occurrence, the precise identities of the sources remain unknown
at this time, but are suspected to be process-related.
1.2 CONTROL AND TREATMENT TECHNOLOGY
A considerable amount of priority pollutant removal is
presently achieved in the industry by the existing control and
treatment practices. Additional removal can be accomplished by
the application of available and demonstrated technologies which
1
-------
would add to or modify existing treatment systems.
the heavy metals for value or reuse in a process does not appear
to be an attractive alternative in those industries where the
product recovery practices now in effect do not already
accomplish this.
The treatment of priority metal-bearing waste streams
results in the production of sludges or residues which are
potentially hazardous and may require special means for handling
and disposal. The massive sludges composed of calcium sulfate
with relatively low concentrations of priority metals can safely
be handled in on-site disposal areas with proper runoff and
leachate control; however, the smaller volume wastes having high
concentrations of metals would require storage in a lined pond
and/or removal to a safe chemical landfill site.
1.3 COSTS OF ADDITIONAL IN-PLANT TREATMENT
The estimated incremental costs of applying the candidate
BAT treatment options represent a relatively small proportion of
the investment and operating and maintenance costs already
committed to the existing BPT level treatment systems. These
costs, however, vary widely from industry to industry and are
highly dependent on site-specific factors.
1.4 SUBCATEGORIZATION
A review of the product/process basis for subcategorization
of the 15 inorganic chemicals designated for initial study
revealed that certain modifications may be appropriate in the
interest of developing effective regulations. The priority
pollutant problem per se impacts subcategorization directly only
in the Chlor-Alkali Industry where the use of graphite anodes
contributes to the generation of chlorinated hydrocarbons. In
the Titanium Dioxide Industry, major process and raw material
differences may justify the creation of a separate segment for
the chloride process using ilmenite ore. The rationale is
presented for creating a subcategory for the combined production
of hydrofluoric acid and aluminum fluoride in view of their
similar waste characteristics and the current practice of
combined treatment at several plants. Hydrogen cyanide
production may be logically subdivided into segments on the basis
of the major process differences related to the Andrussow Process
and HCN production as a by-product in the manufacture of
acrylonitrile.
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1.5 RESTUDY OF REMANDED REGULATIONS
In response to the issues raised by the Fourth Circuit, U.S.
Court of Appeals in remanding effluent limitations guidelines
promulgated for 11 major inorganic chemical products, factors
affecting the control and treatment of pollutant discharges in
those industries have been studied. It has been concluded that
alternative control and treatment technologies to those
originally considered for BAT and NSPS may be appropriate and a
reunion of the corresponding effluent limitations guidelines and
new source performance standards should be considered.
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SECTION 2.0
RECOMMENDATIONS
On the basis of the priority pollutant screening and
verification results and the evaluation of applicable
technologies for discharge control and treatment, it is
recommended that effluent limitation guidelines, new source
performance standards and pretreatment standards for new and
existing sources be proposed for 11 inorganic chemical
manufacturing subcategories. These include:
Chlor-alkali
Hydrofluoric Acid
Titanium Dioxide
Aluminum Fluoride
Chrome pigments
Hydrogen Cyanide
Sodium Dichromate
Copper Sulfate
Nickel Sulfate
Sodium Bisulfite
Sodium Hydrosulfite
In addition, it is recommended that alternative effluent
limitations guidelines and standards of performance to those
which had been promulgated and subsequently remanded for restudy
be proposed for seven inorganic chemical subcategories. These
are industries in which priority pollutant discharges have not
been found in significant quantities, but require appropriate
regulations on the discharge of conventional and nonconventional
pollutants. The subcategories included are:
Hydrogen Peroxide
Hydrochloric Acid
Nitric Acid
Sodium Carbonate
Sodium Metal
Sodium Silicate
Sulfuric Acid
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SECTION 3
INTRODUCTION
3.1 AUTHORITY
3.1.1 The Federal Water Po11ution Control Act Amendments
The Federal Water Pollution Control Act (the Act) Amendments
of 1972 stated the national goal of attaining by, July 1, 1983, a
water quality which provides for the protection and propagation
of fish and shellfish, for recreation in or on the water, and the
goal of eliminating the discharge of pollutants into navigable
waters by 1985.
The Act provides for the achievement of these goals in three
steps by requiring the estblishment of technology-based effluent
limitations and standards of performance. Section 301 (b) of the
Act requires, as the first step attainment by July 1, 1977, of
effluent limitations for point sources, other than publicly owned
treatment works (POTW), based on the application of the best
practicable control technology currently available (BPCTCA, or
simply BPT) as defined by the Administrator pursuant to Section
304 (b). As the second step, the Act as amended an 1977 now
requires the application of effluent limitations for point
sources, other than POTW's, of the best available technology
economically achievable (BATEA, or simply BAT) by July 1, 1984,
for the control of specific toxic pollutants as identified in
accordance with Section 307 (a) . The third and final step in
achievement of the goal to eliminate all discharge of pollutants
into navigable waters by 1985.
The United States Environmental Protection Agency (the
Agency) entrusted with the responsibility to carry out the
requirements of the Act, initiated an intensive effort to develop
the necessary regulatory means which would achieve the stepwise
reduction and elimination of pollutant discharge practices in all
major U.S. Industries. For the Inorganic Chemicals
Manufacturing Point Source Category, the Agency designed a
comprehensive, two phase program to identify the control
parameters and establish the technological basis for regulations
development. Phase I covered 22 Major Inorganic Chemical
Products, (1) and the final regulations for these industrial
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subcategories were published in the Federal Register on
1974. The regulations included specific numerical
limitations and standards of performance applicable to
steps of pollutant control for both existing and new
Zero-discharge requirements specified for
subcategories were to be applied either at the
later. Phase II of the Agency's effort
promulgation of BPT based effluent limitations
group of 27 subcategories referred to
Chemical Products (2). The interim
March 12,
effluent
the three
sources.
many of the
1977 BPT step or
resulted in the
for an additional
as Significant Inorganic
final regulations were
published on May 22, 1975. Taken together, the two groups of
regulations cover 49 inorganic chemical subcategories many of
which include more than one specific chemical product. Although
some toxic pollutant parameters were covered in cases where a
direct relationship to the process was obvious (e.g., mercury
and/or lead in the Chlor-alkali Industry), the main thrust of the
regulations was the control of the bulk pollutant parameters
which accounted, in terms of quantity, for most of the pollution
loading of navigable waters attributable to the manufacture of
inorganic chemicals.
3.1.2 Court Remand of Regulations
On March 10, 1976, the United States Court of Appeals for
the Fourth Circuit decided in E.I. DuPont de Nemours & Company,
et al. v. Train No. 74-1261, to set aside and remand for
reconsideration a number of general definitions and specific
discharge regulations promulgated in 1974. These regulations are
all within Title 40, Parts 401 and 415 of the Code of Federal
Regulations and are listed below:
General Provisions
401.11 (i) -
401.11 (q) -
401.11 (r)
Definition of
Definition of
Definition of
pollutant
effluent limitations
process waste water
process waste water
Chlor-Alkali
415.63
- 1983 step
Hydrochloric Acid
415.72
415.73
415.75
1977 step
1983 step
New sources
Hydrofluoric Acid
415.82
1977 step
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415.83
415.85
1983 step
New sources
Hydrogen Peroxide
415.93
415.95
1983 step
New sources
Nitric Acid
415.102
415.103
415.105
1977 step
1983 step
New sources
Sodium Carbonate
415.152
415.153
415.155
1977 step
1983 step
New sources
Sodium Bichromate
415.173
- 1983 step
Sodium Metal
415.182
415.183
415.185
1977 step
1983 step
New sources
Sodium Silicate
415.192
415. 193
415.195
1977 step
1983 step
New sources
Sulfur ic
415.
415.
415.
Ac id
210
212
213
415.215
Applicability
1977 step
1983 step
New sources
Ti tanium
415.
415.
415.
Diox ide
220
222
223
415.225
Applicability
1977 step
1983 step
New sources
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In the majority of cases the main target of the remand was
the zero discharge regulations from which the industry
petitioners sought relief on grounds of technological
infeasibility. During 1975, the Agency funded a special study of
the remand issues (3) and was prepared to propose amended
regulations. Where appropriate, the results of that study are
included in an Addendum to the present report covering those
remanded regulations for subcategories which have been excluded
from the present study.
Following the court remand of the above indicated Phase I
final regulations, the Agency revoked the Phase II interim final
and proposed regulations published in May, 1975, for Aluminum
Fluoride, Chrome Pigments, Hydrogen Cyanide, and Sodium
Silicofluoride. In this instance, the Agency's intent was to
reconsider the specific effluent limitations established for
these industries (1977 step) in the light of information made
available on process differences between plants and additional
data on the actual concentrations and treatability of the
regulated discharge constituents. The information was presented
to the Agency in the form of various documents prepared by
members of the industries concerned. These sources are also
cited in the appropriate sections of this report.
3.1.3 The Settlement Agreement
Following legal action brought by four environmental groups
in Natural Resources Defense Council v. Train, the Agency
entered into an agreement dated June 8, 1976. In this Settlement
Agreement, the Agency agreed to regulate 65 toxic pollutants
under Sections 301, 304, 306 and 307 of the Act in accordance
with the schedule and provisions stipulated. The original list
of 65 chemicals and classes of chemicals attached to the
Settlement Agreement was redefined to cover 129 chemical
substances, including specific organic compounds, pesticides and
their metabolites, polychlorinated biphenyls (PBC's), cyanide, 13
heavy metals and asbestos. These substances are listed in Table
3-1.
Table 3-1 Recommended List of Priority Pollutants
Compound Name
1. *Acenaphthene
2. *Acrolein
3. *Acrylonitrile
4. *Benzene
5. *Benzidine
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*Carbon tetrachloride (tetrachloromethane)
*Chlorinated benzenes (other than dichlorobenzenes)
7. *Chlorobenzene
8. 1,2,4-Trichlorobenzene
9- Hexachlorobenzene
*Chlorinated ethanes (including 1, 2-dichloroethane,
1,1,1,-trichloroethane and hexachloroethane)
10. 1.2-Dichloroethane
11. 1,1,1-Trichloroethane
12. Hexachloroethane
13. 1,1-Dichloroethane
14. 1,1,2-Trichloroethane
15. 1,1,2,2-Tetrachloroethane
16. Chloroethane
*Chloroalkyl ethers (chloromethyl, chloroethyl and
mixedethers)
17. Bis(chloromethyl) ether
18. Bis(2-chloroethyl) ether
19. 2-Chloroethyl vinyl ether (mixed)
*Chlorinated naphthalene
20. 2-Chloronaphthalene
*Chlorinated phenols (other than those listed
elsewhere;includes trichlorophenols
and chlorinated cresols)
21. 2,4,6-Trichlorophenol
22. Parachlorometa cresol
23. *Chloroform (trichloromethane)
24. *2-Chlorophenol
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*Dichlorobenzenes
25. 1,2-Dichlorobenzene
26. 1,3-Dichlorobenzene
27. 1,4-Dichlorobenzene
*Dichlorobenzidine
28. 3,3'-Dichlorobenzidine
*Dichloroethylenes (1,1-dichloroethylene and
1,2-dichloroethylene)
29. 1,1-Dichloroethylene
30. 1,2-Trans-dichloroethylene
31. *2,4-Dichlorophenol
*Dichloropropane and dichloropropene
32. 1,2-Dichloropropane
33. 1,2-Dichloropropylene (1,3-dichloropropene)
34. *2,4-Dimethylphenol
*Dinitrotoluene
35. 2,4-Dinitrotoluene
36. 2,6-Dinitrotoluene
37. *1,2-Diphenylhydrazine
38. *Ethylbenzene
39. *Fluoranthene
*Haloethers (others than those listed elsewhere)
40. 4-Chlorophenyl phenyl ether
41. 4-Bromophenyl phenyl ether
42. Bis(2-chloroisopropyl) ether
43. Bis(2-chloroethoxy) methane
10
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*Halomethanes (other than those listed elsewhere)
44. Methylene chloride (dichloromethane)
45. Methyl chloride (chloromethane)
46. Methyl bromide (bromomethane)
47- Bromoform (tr ibromomethane)
48. Dichlorobromomethane
49. Tr ichlorofluoromethane
50. Dichlorodifluoromethane
51. Chlorodibromomethane
52. *Hexachlorobutadiene
53. *Hexachlorocyclopentadiene
54. *Isophorone
55. *Naphthalene
56. *Nitrobenzene
*Nitrophenols (including 2,4-dinitrophenol and
and dinitrocresol)
57. 2-Nitrophenol
58. 4-Nitrophenol
59. 2,4-Dinitrophenol
60. 4,6-Dinitro-o-cresol
*Nitrosamines
61. N-nitrosodimethylamine
62. N-nitrosodiphenylamine
63. N-nitrosodi-n-propylamine
64. *Pentachlorophenol
65. *Phenol
*Phthalate esters
66. Bis(2-ethylhexyl) phthalate
67. Butyl benzyl phthalate
68. Di-n-butyl phthalate
69. Di-n-octyl phthalate
70. Diethyl phthalate
71. Dimethyl phthalate
11
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*Polynuclear aromatic hydrocarbons
12. Benzo(a)anthracene (1,2-benzanthracene)
73. Benzo (a) pyrene (3,4-benzopyrene)
74. 3,4-Benzofluoranthene
75. Benzo(k)fluoranthane (11,12-benzofluoranthene)
76. Crysene
77. Acenaphthylene
78. Anthracene
79. Benzo(ghi)perylene (1,12-benzoperylene)
80. Fluorene
81. Phenanthrene
82. Dibenzo (a,h)anthracene (1,2,5,6-dibenzanthracene)
83. Indeno (1,2,3-cd)pyrene (2,3,-o-phenylenepyrene)
84. Pyrene
85. *Tetrachloroethylene
86. *Toluene
87. *Trichloroethylene
88. *Vinyl chloride (chlorethylene)
*Pesticides and Metabolites
89. *Aldrin
90. *Dieldrin
91. *Chlordane (technical mixture & metabolites)
DDT and metabolites
92. 4,4'-DDT
93. 4,4'-DDE (p,p'-DDX)
94. 4,4'DDD (p,p'-TDE)
*Endosulfan and metabolites
95. A-endosulfan-Alpha
96. B-endosulfan-Beta
97. Endosulfan sulfate
*Endrin and metabolites
98. Endrin
99- Endrin aldehyde
12
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*Heptachlor and metabolites
100. Heptachlor
101. Heptachlor epoxide
*Hexachlorocyclohexane (all isomers)
102. A-BHC-Alpha
103. B-BHC-Beta
104. R-BHC (lindane)-Gamma
105. G-BHC-Delta
*Polychlorinated biphenyls (PCB's)
106. PCB-1242 (Arochlor 1242)
107. PCB-1254 (Arochlor 1254)
108. PCB-1221 (Arochlor 1221)
109. PCB-1232 (Arochlor 1232)
110. PCB-1248 (Arochlor 1248)
111. PCB-1260 (Arochlor 1260)
112. PCB-1016 (Arochlor 1016)
113. *Toxaphene
114. *Antimony (Total)
115. *Arsenic (Total)
116. *Asbestos (Fibrous)
117. *Beryllium (Total)
118. *Cadmium (Total)
119. *Chromium (Total)
120. *Copper (Total)
121. *Cyanide (Total)
122. *Lead (Total)
123. *Mercury (Total)
124. *Nickel (Total)
125. *Selenium (Total)
126. *Silver (Total)
127. *Thallium (total)
128. *Zinc (Total)
129. **2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)
*Specific compounds and chemicals classes as listed in the
Consent Decree.
**This compound was specifically listed in the Consent Decree.
Because of the extreme toxicity of TCDD, the Agency recommended
tnat laboratories not acquire analytical standards for this
13
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compound.
The Settlement Agreement also identified 21 point source
categories and specified the scope of application of effluent
limitations, new source performance standards, and pretreatment
standards within each category in terms of the Standard
Industrial Classification (SIC) code numbers. For the Inorganic
Chemicals Manufacturing Point Source Category, the major
industries included are:
SIC 2812 - Alkalies and Chlorine
SIC 2813 - Industrial Gases
SIC 2816 - Inorganic Pigments
SIC 2819 - Industrial Inorganic Chemicals,
Not Elsewhere Classified
Within these industries, the Agency has identified 63
subcategories listed in Table 3-2 for the initial study of the
priority toxic pollutant problem. Most of these subcategories,
49 in all, had already been covered by BPT and BAT discharge
regulations promulgated in 1974 and 1975. Those regulations
established point of discharge control levels for the
conventional parameters such as pH, TSS, TOC, BOD, and oil and
grease. In many cases, specific chemical parameters were
regulated, particularly As , Cr , Cu , Hg , Ni , Pb , Se , Zn , and
cyanide, which are now included in the list of priority toxic
pollutants. Other regulated parameters such as Al, Ba, Fe,
ammonia, fluoride and sulfide are not presently listed as toxic
chemicals but are to be treated as nonconventional pollutants
under future discharge limitations and standards of performance.
Nearly half of the initial 63 subcategories have been
recommended for exclusion from this study on the basis of
specific provisions for such exclusion under Paragraph 8 of the
Settlement Agreement. The bases for these exclusions are as
follows:
No. 63, Ferrous Sulfate, is already covered by the
Titanium Dioxide - Sulfate Process subcategory and
does not require separate consideration.
Nos. 60, 61, and 62 have only one plant each
(or one plant with a wet process discharge) , and
represent nonsignificant discharges of toxic
pollutants. Nos. 27 and 28 are also single
plants, but were covered in screening.
Nos. 36 through 56 have existing BPT regulations
requiring zero discharge of process waste water to
navigable water and there are no known discharges
14
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to a POTW. Continued enforcement of the existing
regulations will provide adequate control of toxic
pollutants.
The remaining 35 nonexcluded subcategories (Table 3-2, Nos.
1 through 35) are covered in this report. This group also
includes the 11 subcategories whose final regulations were
remanded for restudy in E.I. DuPont de Nemours and Company, et^
al. v. Train, and the four additional subcategories whose interim
final or proposed regulations were revoked and reserved by the
Agency.
It was anticipated by the Agency that a substantial number
of the 35 industries to be screened would also qualify for
exclusion under Paragraph 8 on the basis of the analytical
results obtained from the process waste water priority pollutant
screening program. A preliminary prioritization indicated that
the initial detailed study and regulation development would focus
on the first 15 subcategories.
This judgment has been substantially supported by the
analytical results of the screening programs and a number of
additional exclusions are being recommended for subcategories in
which nonsignificant priority pollutant discharges have been
determined. A detailed presentation of the analytical results is
given under the individual subcategory sections of this report.
The additional recommended exclusions include the following:
No. Subcategory
1. Hydrogen Peroxide
2. Carbon Dioxide
3. Carbon Monoxide/Hydrogen
4. Hydrochloric Acid
17. Nitric Acid
19. Sodium Metal
21. Sulfuric Acid
22. Ammonium Chloride
23. Ammonium Hydroxide
24. Barium Carbonate
26. Calcium Carbonate
27. Copper Oxide (one plant)
28. Manganese Sulfate (one plant)
29. Strong Nitric Acid
30. Oxygen and Nitrogen
31. Potassium Iodide
32. Sodium Hydrosulfide
34. Sodium Thiosulfata
15
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35. Sulfur Dioxide
In addition, Sodium Carbonate (No. 18) and Boric acid (No.
25) are being considered as candidates for exclusion and
recommendations will be made following the evaluation of
additional process waste sampling results.
The four remaining subcategories will be included for
screening under Phase II of the inorganic chemicals study. These
are:
13. Silver Nitrate (to be combined with silver bromide,
silver chloride, and other inorganic silver compounds)
57. Calcium chloride
58. Sodium Chloride
59. Sodium Sulfite
3.2 GENERAL APPROACH AND METHODOLOGY
Initiating and undertaking a comprehensive study of the
priority pollutant problem in the Inorganic Chemicals Industry
was necessarily preceded by an intensive evaluation by the Agency
of the kinds of data and supporting information that should be
assembled as a basis for the development of regulations. All
major decisions on the identity of pollutants and the
establishment of effluent limitations and standards of
performance for each subcategory had to be supportable by
documented evidence collected from operating production
facilities. Similarly, the necessary information on production
rates, processes, raw materials, water use, waste sources, and
treatment technologies in practice had to be acquired with
sufficient detail and breadth of coverage to permit an analysis
of the engineering and economic variables that are characteristic
of each subcategory. Priority pollutant control regulations
would be based on the application of best available technology
for treatment and reliable performance evaluations for the
removal of specific waste substances.
The following paragraphs briefly describe the major study
tasks and their results as they are presented in this report.
3.2.1 Industry Data Base Development and Subcategorization Review
Information from individual manufacturers and previous study
documents were reviewed in detail and an evaluation of the
appropriateness of subcategorization was performed. Section 4
presents a discussion of the factors considered in
16
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subcategorization and presents rationale for maintaining the
present scheme of subcategorization for the industries studied.
3.2.2 The Screening and Verification Sampling Programs
The collection of detailed analytical data on conventional,
nonconventional and priority pollutant concentrations in raw and
treated process waste streams was completed in a two-phase
sampling program. The first phase, for screening, was designed
to provide a representative, one-time 72-hour sampling of a plant
in each subcategory in order to determine the presence of
priority pollutants and to evaluate their potential environmental
significance. The sampling and analytical methodology is
described in Section 5, along with the basis for making a
decision on the need for verification sampling in each
subcategory.
3.2.3 Engineering Evaluations
Section 6 describes the procedures and sources used in
developing the industry productions and wastewater generation
characteristics that form the basis of the model plant concept.
The sources of detailed process and waste treatment information
are also presented. Section 7 contains an evaluation of
treatment technology presently applied in BPT systems and
advanced technologies that may be recommended for BAT and NSPS
applications. Section 8 provides estimates of the treatability
of selected priority and nonconventional pollutants to be applied
in the development of achievable performance characteristics for
specific technologies. Section 8 also presents a discussion of
the approach taken in the statistical analysis of long term
monitoring data. The statistically derived parameters, including
variability factors for 24-hour maximum and 30-day averages are
presented in Appendix A. Section 9 lays the groundwork for the
estimation of pollutant removal performances for each nonexcluded
subcategory- The candidate priority pollutants to be controlled
in each subcategory are identified on the basis of the screening
and verification data and the rationale for the application of
advanced level technologies is presented.
3.2.4 Treatment System Cost Estimates
Section 10 presents the general approach to cost estimating,
discusses the assumptions made, and gives the detailed cost
estimates for alternative levels of treatment and control. For
each subcategory verified, the total estimated installed cost of
a typical BPT treatment system is developed on the basis of the
model plant design specifications and estimated incremental costs
are given for each of the advanced level treatment alternatives.
17
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SECTION 4
SUBCATEGORIZATION REVIEW
4.1 BASIS FOR SUBCATEGORIZATION
4.1.1 Factors Considered
The inorganic chemicals industry is very large and
diversified and therefore has been segmented into subcategories
for the purpose of establishing effluent guidelines. Factors
taken into consideration for subcategorization include: raw
materials used, product produced, manufacturing process employed,
geographical location, size and age of equipment and facility
involved, nonwater quality aspects of waste characteristics,
water pollution control technology, treatment costs, energy
requirements and solid waste disposal. Following is a discussion
of each of the general factors considered for this industry.
Raw Material
Different raw materials are used to manufacture a wide
variety of products, and vary from raw brines and ores to pure
reagent chemicals. Some proceses use waste or by-product streams
from other plants or from other processes within the same plant.
Because of this diversification, raw material
characteristics do not generally constitute a logical basis for
subcategorization. Variations in raw material quality or purity
are not normally sufficient to cause a great difference in waste
water treatment needs, except in the case of trace toxic
materials which may occur in some sources but not in others.
Dominant Product
Subcategorization by chemical name of the dominant inorganic
chemical produced involves the least ambiguity in applying
standards to a given point source. This is critical because of
the great variety of product mix, manufacturing processes, waste
water constituents, and other factors at existing plants.
Subcategorization by product becomes less useful as product mix
increases in complexity because multi-product waste water also
becomes more complex and less susceptible to simple uniform
18
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treatment.
A subcategory established on the basis of product
manufactured might have two or more different processes but, in
the majority of cases, the characteristic of the waste waters is
similar and the same treatment technology can be applied for
different process waste waters. If two or more dissimilar
processes produce waste water of different quality, and different
treatment technologies have to be used, then the subcategory has
to be further classified or segmented, for example, the
Chlor-alkali Industry.
Manufacturing Process
Typically.- inorganic chemicals are manufactured for captive
or merchant use in four or more steps starting from raw material
to final product. Two or more different products might use the
same process but then the raw materials used, process sequence,
control, recycle potential, handling, and quality control will
vary, producing wastes of different quality. Primary
subcategorization, therefore, by process is unlikely to be
useful. However, secondary subcategorization by process has been
necessary in some cases.
Geographical Location
Inorganic chemical plants exist in all parts of the United
States but subcategorization on this basis is not appropriate.
Geographical location is important in analyzing the feasibility
of various treatment alternatives. Evaporation ponds are
functional only in areas where evaporation exceeds rainfall.
Ocean dumping and deep well disposal are possible only in certain
areas, and must be consistent with local, State and Federal
laws. The possibility of ground water contamination may preclude
the use of unlined holding and settling ponds in many locations.
Thus the influence of geography, climate, geology, etc. is
reflected in waste treatment modifications and is primarily
manifest in the cost of treatment. This, of itself, is not a
good basis for subcategorization.
Plant Size
Plant size and production capacity were not found to affect
the characteristics of the waste produced. Although plant size
can affect treatment cost, this variability can be expressed
graphically or mathematically without the need for further
segmentation of the category.
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Plant Age
Plant age is not related to waste water volume and it is not
a factor in terms of waste water quality. Because most plants
have been enlarged or modified from their original status, plant
age is not easily calculated and therefore not a reasonable basis
for subcategorization.
Nonwater Quality Characteristics
Airborne emissions from manufacturing operations can be kept
within air quality control limits through the use of cyclones,
wet scrubbers and other methods. The nature of the air pollution
is related to the products(s) manufactured and/or the raw
material used. Since both of these elements vary widely within
the inorganic chemicals industry, there is no logic in
subcategorization on the basis of nonwater quality
characteristics.
Treatment Cost
From a technical viewpoint, subcategorization by common
technological requirements for treatment processes could provide
a logical basis for selecting one or more unit processes to
accomplish the same treatment function, regardless of the source.
For example, residuals of dissolved heavy metals will respond to
lime precipitation and sedimentation at high pH without respect
to the specific origin of the metals. This "building block"
concept could conceivably result in selecting various
combinations of unit processes to meet the treatment
requirements. However, if the treatment cost must be expressed in
terms of dollars per unit production, this method of
subcategorization crosses product lines and interferes with
comparison of treatment costs based on the production of a
specific chemical. Even if the unit operation is commonly
applicable for treating waste flows of different products, the
cost of treatment will vary due to variations in quality, loading
and flow rates and therefore subcategorization on the basis of
treatment cost is not recommended.
Energy Cost
Manufacturing processes in the Inorganic Chemicals Industry
typically have large energy requirements. In contrast, waste
water treatment processes consume a small fraction of the total
energy used. There appears to be no major energy requirements
for the waste water treatment facility and subcategorization
on the basis of energy cost is not justified.
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Solid Waste
Not all inorganic manufacturing processes produce solid
wastes. Those that do practice various disposal methods, such as
on-site landfills, contract hauling to approved dump sites or
incineration. Solid waste disposal becomes very site specific
and exhibits a wide range of costs. Due to the lack of
uniformity within the industry, solid waste generation and
disposal practices are not considered to be a satisfactory basis
for subcategorization
4.1.2 General conclusions
If effluent limitations are to be tied to units of
production, only one method of primary subcategorization is
broadly applicable to the inorganic chemicals point source
category; that is, subdivision by dominant product. However,
there are two subcategories, chlorine and titanium dioxide, which
need further subdivision based on the difference in the quantity
and quality of the waste water from the processes.
4.2 SECONDARY SUBCATEGORIZATION
4.2.1 Chlor-Alkali
Mercury and diaphragm cells are the two distinct types of
electrolytic cells that are currently used in the production of
chlorine and caustic soda. Major process differences between
mercury cell and diaphragm cell plants produce corresponding
differences in the volume and nature of waste water generated. A
principal difference is the presence of mercury as a contaminant
in the waste waters from the mercury cell process and asbestos in
the diaphragm cell plant wastes. In addition, the total
suspended solids (TSS) discharges from the two processes are
significantly different. The TSS discharges from diaphragm cell
plants are generally larger than from mercury cell plants, due to
the higher volumes of contact and noncontact water used. Also,
in diaphragm cells a large amount of water is used and an
appreciable quantity of waste water is produced in the caustic
evaporation process. Such water is not produced in mercury cell
plants. The quantity of waste water generated from the diaphragm
cell plants is almost double that of the mercury cell plants for
the same chlorine production capacity. Based on the quantity and
characteristics of the waste water, further subcategorization is
j ustified.
21
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4.2.2 Titanium Dioxide
Two major ores, rutile and ilmenite, are used for the
manufacture of titanium dioxide. The ilmenite ore contains 40-70
percent titanium dioxide (Ti02), up to 35 percent ferrous oxide,
and 25 percent ferric oxide. Rutile ore contains 90 percent
Ti02. Two processing techniques, the sulfate process and the
chloride process, are used to extract titanium dioxide from the
ores.
The sulfate process uses ilmenite ore and sulfuric acid as
raw materials. The chloride process uses rutile ores and
chlorine. The high grade rutile ore is expensive and its
availability is declining. New technological advances in recent
years have alleviated the raw material shortage problem. By
upgrading the ilmenite ore quality, the chloride process can be
used to produce titanium dioxide of high purity. Because of the
difference in quality and quantity of waste waters generated from
the sulfate and chloride processes using the two different ores,
the titanium dioxide industry may be further subdivided into
three segments as follows:
a) Sulfate process
b) Chloride process using rutile ore
c) Chloride process using ilmenite ore
The sulfate process generates large amounts of strong and
weak sulfuric acid water-borne wastes. Application of pollution
control technology to the acid wastes generates about five times
as much gypsum as product. The chloride process generates large
amounts of dissolved metal chlorides and the treatment technology
is expensive. Solid waste from both processes present difficult
disposal problems. These solids include ferrous sulfate and a
hydrated by-product from the sulfate process and heavy metal
sludges from the chloride process. Ilmenite ore has to be
upgraded before it is used to extract titanium dioxide by the
chloride process, and this beneficiation process step generates
additional wastes.
Ilmenite ore is a low-grade ore containing 40-70 percent
Ti02 before the use of chloride process. The beneficiation
process creates some additional wastes streams. There is more
than one patented beneficiation process and one of the processes
claims that no waste water is generated and only a solid waste
needs to be treated or disposed of separately. Thus the same
treatment technology can be used for both the rutile and upgraded
ilmenite ore for the process waste water except the additional
treatment of some streams generated from the beneficiation step.
Therefore, further subclassification based on the amount and
22
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characteristics of the waste water appears to be justified,_and
the three process subdivisions indicated above are appropriate
for this purpose.
4.2.3 Hydrogen Cyanide
Hydrogen cyanide is made from two different processes, the
Andrussow process and as a by-product of _ acrylonitrile
manufacture. In the Andrussow process, air, ammonia, and natural
gas are reacted to produce the dominant product hydrogen cyanide.
Water-borne wastes from the process consist principally of
ammonia and sulfates in addition to cyanide and nitriles.
The dominant product in the other process is acrylonitrile.
The required treatment technology for the Andrussow process is
not applicable to the HCN by-product stream in an acrylonitrile
plant since neither solid nor water borne wastes are generated.
All tail gas streams are burned to destroy any unrecoverable HCN
before venting to the atmosphere. Further subclass!fication by
process seems logical.
4.3 INTEGRATION OF SUBCATEGORIES
4.3.1 Hydrofluoric Acid and Aluminum Fluoride
Aluminum fluoride is predominantly produced by the reaction
of hydrated alumina with hydrogen fluoride, although one plant
produces aluminum fluoride from fluorosil icic acid, a by-product
of phosphoric acid. With one exception, all the aluminum
fluoride plants are integrated with hydrogen fluoride (or
hydrofluoric acid) production.
The two major uses of hydrogen fluoride are in the
fluorocarbon industry and as raw material in the manufacture of
aluminum fluoride. A ban on the fluorocarbon propellants has
curtailed the use of hydrogen fluoride in that industry and it
will be completely stopped in 1978. The selling of hydrogen
fluoride in the merchant market will decline in the future and
the primary use will be limited to the production of aluminum
fluoride and fluorocarbon plastics (e.g., Teflon, Kel-F, etc.)
until some other major use is found.
For both products (HF and A1F3), process waste waters are
generated by the various gas scrubbers and by leaks and spills.
In both cases, air pollution control scrubber effluents contain
mainly fluoride, acidity and sulfate. The fluoride is present as
the free ion as well as various complex fluoro anions. Calcium
fluoride, generated as a solid waste, is a disposal problem for
23
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both the subcategories because of its moderate toxicity. Only
one additional solid waste, gypsum (calcium sulfate), is
generated from the hydrogen fluoride manufacture alone, and it
can be treated and handled independently-
Combining hydrofluoric acid and aluminum fluoride into a
single subcategory does not appear to offer any regulatory
advantages when the two products are manufactured at the same
plant location. The waste waters associated with the two
products are similar and a common treatment facility is normally
utilized. However, the combined manufacture of these
products does not in itself create a unique or unusual situation,
either with regard to the waste water treatement requirements or
the compliance with discharge regulations. Although the waste
gypsum produced at an HF plant supplies enough calicium for
adequate fluoride removal from neutralized scrubber waste waters
generated by both HF and AIF3 production, the applied treatment
technology is essentially the same as that applied by
manufacturers of either product alone. Therefore, the effluent
water quality and the mass emission limitations would also be
expected to be the same. Further, the opportunities for drip
acid recycle (or the hydrolysis of complex fluorides prior to
treatment) and scrubber water recycle are a function of plant
design and age, rather than product mix.
In view of these considerations, a recommendation for the
creation of an HF/AIF3 combined product subcategory is not being
made at this time.
4.4 SUMMARY
The recommended subcategorization with process subdivisions
include the following:
Subcategory Process Subdivisions
Chlor-Alkali Mercury Cell
Diaphragm Cell
Titanium Dioxide Sulfate
Chloride-Rutile
Chloride-Ilmenite
Hydrogen Cyanide Andrussow Process
Acrylonitrile By-Product
24
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SECTION 5
SCREENING AND VERIFICATION SAMPLING PROGRAMS
5.1 SCOPE AND METHODOLOGY
The specific objective of the sampling programs was to
establish the extent of the need for regulation of priority
pollutant discharges in the inorganic chemicals industry in terms
of factual information derived from the chemical analysis and
flow measurement of representative process raw waste water
streams and treated effluents. Prior to this study, most of the
information available on priority pollutants in this industry has
been concerned with a relatively small number of known
process-related substances contaminating a variety of direct and
indirect contact process waters which may be discharged from a
production facility. There had been no previous requirement for
a comprehensive survey of waste water chemistry addressing the
possibility that a large number of other potentially toxic
substances could be present, albeit at extremely low
concentrations.
The screening phase of the sampling program was designed to
ascertain the presence in each subcategory of any of the 129
listed priority pollutants at raw waste concentrations or daily
loadings which, if untreated, could be environmentally
significiant. Screening is based on the sampling of one or more
typical manufacturing operations in each subcategory. Where
such pollutant concentrations were found, additional plants were
sampled during the verification phase for confirmation and
further quantification of data on the particular priority
pollutants in question. As a goal, screening and verification
sampling, in each subcategory where priority pollutants were
found in significant concentrations, would cover a sufficient
number of plants to account for 75 percent or more of the current
total U.S. Production.
A detailed description of the screening and verification
programs is presented in the paragraphs below.
25
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5.1.1 Selecting Plants and Making Preliminary Contacts
In each subcategory, plants were selected for screening on
the basis of the following general criteria:
1. Minimal product mix and no organic product lines
which could increase the potential for inter-
process cross contamination of waste waters.
2. Presence of a physical chemical treatment facility
rather than a biological one, or no treatment system.
(Biological systems are neither widely used nor generally
applicable in the inorganic chemicals industries.)
3. Manufacture of industrial grade products in volume,
rather than low volume reagent grade products.
4. Median production capacity within the subcategory.
5. Segregated waste streams to facilitate sampling.
6. NPDES discharges rather than POTW discharges,
since treatment for a NPDES discharge is usually
more extensive.
7. Geographical clustering of selected plants to
facilitate field logistics.
Plants were identified which satisfied as many of the
criteria as possible, and preliminary contacts with corporate
representatives were made by phone. If requested, a letter was
written to describe the objectives of the sampling program and to
cite the legal authority of the Agency and its sampling
contractor under Section 308 of the Federal Water Pollution
Control Act Amendments of 1972. Secrecy agreements, when
required, were executed at this time for the protection of any
company proprietary information which might be disclosed to the
sampling contractor.
Prior to the actual sampling of waste streams, a lead visit
to the selected plant was made to gather background information,
confirm and update any 308 Questionaire responses, and to obtain
additional technical information regarding processes and waste
treatment practices. Sampling sites were selected and described
26
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in relation to a detailed waste source inventory and a flow
diagram of the process and waste treatment system. Arrangements
were made for the subsequent sampling visit and the details of
the lead visit and sampling point descriptions were documented in
an interim report to the Agency.
5.1.2 Screening and Verification Sampling
Collection of Samples for Screening
In the screening phase of the sampling program, the specific
objective was the detection and quantification of water-borne
waste constituents included on the list of 129 priority
pollutants (Table 3-2). Each sample of an individual raw waste
stream, a combined waste stream, or a treated effluent was
collected where possible by an automatic, time series, compositor
over a single 72-hour sampling period. Where automatic
compositing was not possible, grab samples were taken at
intervals during the same sampling period and composited
manually-
Each sample was divided into several portions and preserved,
as required for different types of analysis, in accordance with
the procedure established by EPA (4) for the measurement of
priority pollutants.
Samples were also taken from the composites, or as
individual grabs, for the analysis of the classical (BPT)
pollutants.
Collection of Samples for Verification
The objective of verification sampling was to confirm the
presence and further quantify the concentrations and waste
loadings of the priority pollutants found at significant levels
during the screening phase of the program.
The established protocol for verification sampling required
the collection of three 24-hour composites at each sampling
point. Again, where composites could not be taken with automatic
samplers, grab samples were taken periodically over the same time
period and composited manually.
Sample Shipping
All samples, individually labeled, were placed in large
plastic bags, which were then placed in a waterproof insulated
27
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shipping container. Enough ice was included to maintain a
temperature of approximately 4 degrees C. during shipment to the
laboratory.
Containers were shipped by the best available route, usually
air freight, arriving at the laboratory on the same or the next
day.
In order to maintain the chain of custody and to keep track
of samples, sampling personnel kept logs of samples taken in ink
in page numbered hard-bound books. The data recorded included:
date, time, plant code, number, sample type, and sampler. This
information was also included on the label of individual samples.
Prior to their arrival at the laboratory, a list of samples
shipped, including number, type of samples, and analysis to be
performed, was sent to each department supervisor to alert them
of incoming work.
A master analytical control chart was maintained which
included: date sample was received, date due, number and type of
each sample, and the analysis required.
At time of analysis, the individual samples were distributed
to the analytical chemists along with a list which included:
I.D. number of sample, type of sample, analysis required, date
samples received, due dates.
Upon completion of analysis, the sample was sent back to the
refrigerator and placed in identified bins. All samples were
kept in the refrigerator at 4 degrees C. when not being analyzed.
A list of completed samples was then sent to the EPA Sample
Control Center.
5.1.3 Analytical Methodology for Priority Pollutants
The analytical protocol for the screening and verification
of priority pollutants was established by the EPA in April 1977.
The specified analytical methodologies were employed without
modification except where noted below in connection with priority
metals analysis during verification.
Implementation of the methodology and quality assurance
provisions required the establishment of special sample handling
and control procedures specifically suited to each type of
analysis. These procedures, together with a discussion of the
achievable detection limits for each parameter or group of
similar parameters are presented in the following paragraphs.
28
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Trace Metal Analysis
Figure 5-1 shows a data flow diagram for metals analysis. A
set procedure was followed in the laboratory to generate the
analytical values and the quality control data. The data flow
diagram shows the actual sequence employed in verification
analysis and the following notes, which are keyed to the diagram,
provide additional information on the procedures:
(1) Blanks - two for each set of analyses digested.
Duplicates - one every seventh sample.
(2) Quality Control at AA Operator Level:
Blanks - These were run at the beginning and the
end of every set analyzed for each metal.
Also, air blanks were run on furnace, or
heated graphite atomizer, (HGA), after any
sample with a large positive value.
Standards - Three different concentrations were
run at the beginning and end of every set
analyzed for each metal. Standards were
also run every tenth sample during the
analysis of a set.
Spikes - These were run every seventh sample,
and were made by taking a mixture of equal
parts of a sample and standard and comparing
the resulting absorbance with individual
sample and standard absorbances.
Duplicates - For furnace analysis, the sample
was run twice when the absorbance was low
to identify errors.
The average of the two values was used as
the determinate value.
(3) UTD = Unable To Determine due to matrix
interferences.
(4) Criteria Employed in Spike Selection:
(a) Samples were chosen to be spiked
based upon the following criteria:
- those which were not subject to interference
effects.
- those that had a measurable concentration of the
metal being determined.
- those whose concentration was in the linear
range of the instrument.
- approximately every seventh sample.
29
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FIELD SAMPLING
PRESERVATIVE ADDED
ICED, AND AIR
SHIPPED
RECEIPT, LOG IN SAMPLES
AND REFRIGERATE
QUALITY CONTROL BLANKS AND
DUPLICATES CREATED (1)
to
O
PREPARATION
BY
ACID DIGESTION
:^^ 1 ATOMIC ABSORPTION ANALYSIS (2) I
1
RNACE FLAME
Pb.Sb.Tl) [* (Ag,Be,Cr,Cu,Ni
1
1
DETERMINATE OFF-SCALE
VALUE RESULT
i
|_ DILUTE
LYSIS 1 SAMPLE
\^
^\^
1 ^"^-A.
DETERMINATE _
VALUE ^
,Zn)
1
DETERMINATE
VALUE
1
CALCULATIONS &
ANALYSIS OF
RESULTS
^
f-
r*
^
VAPOR GENERAT
-(Hg)
1
1
OFF-SCALE DET1
RESULT i
1
DILUTE
SAMPLE
SELECTION OF
SPIKED (4)
ICN
|
EBMINATE
UAIJUE
HYDRIDE GEI^ERATION
(As,Se)
ANALYSIS
Figure 5-1 . Sanple flow sheet for nefcals.
-------
(b) The level of spike chosen was
controlled by the following factors:
- it should be approximately 40-60 percent
of the determinate value.
- the determinate value absorbance + spike
absorbance must give total absorbance
that was within the linear range.
(c)
A reagent blank was run with each set of spiked
samples prepared.
During the screening phase of the sampling program, the
standard protocol followed for metals analysis was:
1. Twelve elements were determined by AA spectrophotometry
in the furnace (HGA) mode.
2. If subject to matrix interference (UTD), they were then
determined in the flame mode.
3. Mercury was determined by the standard cold vapor
method.
Certain changes in analytical protocol were instituted
during verification analysis in order to avoid the excessive
matrix interference experienced during screening when the heated
graphite atomizer (HGA) was the primary method applied to the
analysis of 12 of the metals. The modified protocol for metals
was:
1. Six elements were determined by flame only,
namely, Ag , Be, Cu, Cr, Ni and Zn.
2. Four elements were determined by furnace (HGA),
namely, CD, Pb , Tl and Sb. If interference
occurred, Cd, Pb, Tl and Sb were determined
by flame.
3. Hg was still analyzed by the cold vapor method.
This modification reduced the number of preparations per
sample from three to two and achieved adequate detection limits
which were still well below the verification criteria levels.
Additional modifications were made during the verification
program to improve the reproducibility and detection limits for
Hg, As and Se. These were:
1. The cold vapor procedure for Hg was modified to
eliminate the pump and allow dilution and rerun
from the same sample. This saved time and increased
31
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reproducibility.
2. Selenium and arsenic were determined
by hydride generation using sodium borohydride
(NaBH4). This greatly minimized problems associated
with matrix interference. The method is very
reproducible and the detection limits were at
levels well below the verification criteria for
these two elements.
After the above modifications were adopted, screening
samples which originally were unable to be analyzed, or which
were recorded at excessively high "less than" values due to the
effects of matrix interferences on the achievable detection
limits, were rerun. Satisfactory results were then obtained in
nearly all cases due to the greatly improved sensitivity and
reproducibility.
Table 5-1 presents a summary of the analytical detection
limits for each of the 13 priority metals using the original
protocol and the two subsequent modifications which were applied.
The detection limits shown reflect the maximum sensitivity
that can be consistently obtained in the absence of matrix
interferences.
Organic Compound Analysis
The organic priority pollutants were determined by the
standard protocol which includes sample preparation, extraction,
and analytical methodologies. Extractions were carried out using
methylene chloride in the case of the acid and base/neutral
organic fractions and with hexane/methylene chloride to obtain
the pesticide containing fractions. The acid and base/neutral
fractions were reduced in volume and analyzed by gas
chroraatography-mass spectrometry (GC/MS). The pesticides were
analyzed by electron capture gas chromatography followed by GC/MS
confirmation of positive results. Volatile organics were
analyzed by the purge and trap method of introducing the material
into the GC/MS inlet system.
Analysis of Cyanide and Chromium VI
The standard methods for the wet chemical analysis of total
cyanide and cyanide amenable to chlorination were utilized.
Cyanide analysis is subject to several sources of interference
including:
32
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TABLE 5-1
ANALYTICAL DETECTION LIMITS FOR METALS
(assuming no matrix interferences requiring dilution
of sample)
Element
Antimony, Sb
Arsenic, As
Beryllium, Be
Cadmium, Cd
Chromium, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel, Ni
Selenium, Se
Silver, Ag
Thallium, Tl
Zinc, Zn
Original Screening
Protocol
(ng/l)
HGA *
EGA.
HGA
HGA
HGA
HGA
HGA
Cold Vapor
HGA
HGA
HGA
HGA
HGA
10
3
0.2
1
1
1
10
0.5
1
9
0.5
2
1
First Modification
of Protocol
(vg/1)
HGA
HGA
Flame
HGA
Flame
Flame
HGA
Cold Vapor
Flame
HGA
Flame
HGA
Flame
10
3
15
1
25
20
10
0.5
25
9
15
2
25
Second Modification
of Protocol
(yg/D
HGA
Hydride
Flame
HGA
Flame
Flame
HGA
New Cold
Flame
Hydride
Flame
HGA
Flame
10
10
15
1
25
20
10
Vapor 0.5
25
10
15
2
1
Heated Graphite Atomizer
33
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Metals - The presence of Fe , Cd, Ca, Ni, Ag, and Zn may
causelow results due to the formation of stable complexes with
cyanide. The iron complexes may form insoluble precipitates
which are particularly difficult to break up both at the time of
alkaline chlorination of the sampled waste water and during the
chemical analysis for cyanide.
Oxidizing agents - The presence of free chlorine in _ the
waste "water sample will destroy cyanide and cause low analytical
results. The addition of ascorbic acid to destroy chlorine at
the time of sampling is intended to mitigate this problem. Other
oxidizing agents such as peroxides and chromates may also react
with cyanides over a period of time and cause low results.
Sulfides - Sulfide or bisulfide will interfere in the
analysis of cyanide by reacting with the colorometric reagents.
The presence of sulfur dioxide or bisulfite in the waste
water sample should have no appreciable effect on cyanide
results. Detection limits on the order of 1-4 ug/1 can be
achieved by the analytical method employed, but the results have
to be interpreted with regard to the possible interfering
components of the sample.
The determination of chromium VI in waste water samples is
also subject to a number of interferences which can take effect
either during sampling and storage or during analysis.
Acids - Samples taken and held at a very low pH can
experience the conversion of other forms of chromium into Cr VI
causing a positive interference.
Reducing agents - Samples containing sulfur dioxide,
bisulfite, bisulfide, sulfide, ferrous iron, and other reducing
agents will result in low values of Cr VI by converting it to Cr
III. Under these conditions the chromates originally present
would be included in the total chromium determination but the
analytical results for hexavalent chromium would be
proportionately low.
The detection limits for Cr VI using the diphenylcarbazide
colorometric method are on the order of 1-3 ug/1 in the absence
of substances which interfere with color development.
Asbestos Fiber Analysis
The_analysis of selected samples for asbestos fiber
(cnrysotile) was conducted by the recommended method utilizing
transmission election microscopy with selected
34
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area electron diffraction as described by Dr. Charles Anderson
(EPA, Athens, Georgia) at the Analytical Protocol Meeting in
Denver (November, 1977).
Conventional and Nonconventional Pollutants
All techniques used for the analysis of BPT control
parameters (conventional and nonconventional pollutants) were
those recommended by the Agency. The list of approved test
procedures was published in the Federal Register on October 16,
1973 (38 FR 28758) and may be also found in Title 40 of the Code
of Federal Regulations (40 CFR 136).
5.1.4 Quality Assurance Provisions
The Agency and the contractor's analytical laboratories
maintain consistently high standards for accuracy and quality
control. As an in-house requirement, a minimum of ten percent of
all samples are routinely run in duplicate. Quantitation is
based on standards that are prepared in the same matrix as the
samples. The standards are also checked by participation in the
EPA Reference Sample Program that utilizes a double blind
technique.
Additionally, outside laboratories are retained for checks
on quality by analyzing split samples and running submitted
standards. Accuracy is also insured by analysis of a minimum of
fifteen percent of all samples with spikes by the method of
standard additions. The spikes are added prior to sample
preparation and are carried through the entire sample analysis
procedure.
The contractor's laboratories have consistently maintained
the standards for laboratory certification which are imposed by
the State of California. Certification is dependent upon the
accurate performance of routine analyses on check samples
submitted by the State, as well as on-site inspections by the
State of California's Sanitation and Radiation Laboratory,
Department of Fish and Game, and the U. S. Environmental
Protection Agency, NEIC, Denver, Colorado.
The quality assurance provisions outlined in the EPA
Protocol for GC/MS Analysis of Priority Pollutants are rigorously
adhered to with one added precaution, namely, the use of internal
standards as a means of measuring recovery. Although not
required by the protocol for pesticide analysis, this technique
is utilized as an in-house quality control requirement to insure
the accuracy of results in this analysis.
The high sensitivity of instrumentation used in trace
organic chemical analysis dictates that contamination of the
35
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samples from any possible source must be diligently guarded
against. Accordingly, only glass sample containers with
Teflon-lined lids were used and these were subjected to a three-
step cleaning procedure prior to use, even though only new liners
and glass containers were used. All glassware used_for sample
preparation and analysis was subjected to a dual cleaning system.
The sample extraction and preparation rooms were dedicated
solely to priority pollutant analysis, and have their own
ventilation systems that are isolated from^ the other sample
preparation and receipt areas of the laboratories.
A documented system of existing practices, including
calibrations and operational checks is maintained to assure
uniformity of performance and to serve as a basis for alteration
of standardization intervals. A chemist is assigned full time to
maintain this system, assure strict record formating and
controls, and to direct the quality control program of the
laboratories. The primary vehicle of this system is the quality
assurance manual containing the detailed procedures used in
sample preparation and analysis, and the complete records of all
quality control standards, blanks, spikes and duplicates.
5.2 THE BASIS FOR VERIFICATION SAMPLING
The screening program results were evaluated to identify
those priority pollutants that were present at significant
concentration or significant daily loadings. Concentrations or
loadings which could be reduced by the highest quality treatment
systems were considered significant.
1. A subcategory which had a significant raw waste
concentration of any priority pollutant(s)
would be subject to verification sampling, and BAT-
based regulations would likely be proposed by the
Agency for the treatment and control of that
priority pollutant.
2. A subcategory which had no significant raw waste
concentration of any priority pollutant
would not be subject to verification
sampling and would likely be excluded from
regulatory coverage at this time in accordance
with the provisions for exclusion under
Paragraph 8 of the Settlement Agreement.
36
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In analyzing screening data, only those pollutants
attributable to process sources were considered. Pollutants
which result from cooling tower operations, corrosion or
corrosion control, control of biological growth, or any other
operation not directly tied to the production process were not
used as a basis for verification.
5.3 THE VERIFICATION PROGRAM
After the decision was made to verify the presence of
priority pollutants found in the screening of a subcategory,
verification plants were selected. The basis for selection was
essentially the same as that used in selecting screening plants.
In some subcategories, plants which had been screened were
also sampled again in verification.
The number of plants selected for verification in each
subcategory was roughly proportional to the number of existing
plants in that subcategory with a maximum of five plants
selected. In small subcategories (relatively few production
facilities), an effort was made to select a sufficient number of
plants to account for the majority of the total U.S. Production.
Very small producers were not selected.
The sampling methods and analytical protocol used in
verification have been described in Sections 5.1.2 and 5.1.3.
When the verification phase of the program was initiated, an
important decision was made with regard to metals analysis.
First, in view of the frequent presence of metal contamination in
the wastes screened, and the inability in some cases to show a
direct relationship between certain metals found and the known
process chemicals or the materials of construction, it was
decided that all 13 of the priority metals should be determined
again during verification, regardless of whether they were found
in screening. This was intended to provide a much more complete
data base than would be obtained by running verification analyses
for only those metals found in screening to exceed the
verification criteria levels at the time of sampling.
37
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SECTION 6
PROCESS AND WASTE TREATMENT
INFORMATION DEVELOPMENT AND EVALUATION
6.1 INDUSTRY DATA BASE DESCRIPTION
6.1.1 Data Acquisition
Information and data on the inorganic chemicals industry
were obtained from a number of sources. These sources included
literature reviews, plant visits and data collection, telephone
contacts, and industry responses to the Section 308
Questionnaires. The type of material gathered from these sources
is briefly discussed below.
Literature Review
A review of the literature has been conducted to identify
and collect information related to manufacturing processes, raw
materials, water use and wastewater sources, wastewater treatment
technology, raw waste characteristics, and economic data.
Relevant articles in the form of reports, books, papers,
conference presentations and periodicals were identified by
computer search and are presented in the reference section of
this report. This information was incorporated into a
broad-based assessment of process and technology practices aimed
at selecting the best available treatment technology and best
demonstrated technology for the various industry subcategories.
It also provided the background required for evaluating the
subcategorization of the industries.
Plant Visits
During the screening and verification phase of this project,
much information was gathered from individual plants relating to
production capacity, manufacturing processes, waste flows, water
reuse, waste water treatment systems and performance, and best
management practices (BMP). The lead visits also provided an
opportunity to update and clarify some of the information given
in the 308 responses.
38
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Telephone and Direct Contact
Numerous contacts were made with knowledgeable persons in
both industry and government to gather and exchange information
concerning all phases of this study. These sources are cited in
the text as personal communications.
308 Questionnaire Responses
The basis for much of the work in this study is the set of
responses from industrial inorganic chemical firms to the 308
data requests.
Data from 284 manufacturers' responses were
project team for the development of appropriate
the inorganic chemicals subcategory. Industrial
their compliance with the needs of the 308
provided a valuable industry-wide data base used
this analysis.
utilized by the
guidelines for
firms, through
Questionnaire,
extensively in
Essential data elements from each questionnaire were
extracted for the purpose of creating a working data base for
this report. Specific elements selected for this smaller,
more-manageable data base are given in the outline on the
following page.
These data provided the basis for
through a profile of each industry.
questionnaire data, industry totals for
(for the respondents) were available.
the subcategory review
After compilation of the
capacity and production
In addition, derivative
quantities such as percent utilization, effluent per ton of
product, conversion to metric units, were compiled from the data
elements listed below:
39
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308 Questionnaire Response Data
Data Elements used in this
Inorganic Chemicals Guidelines Study
Datum Reference
Manufacturer
Product
Description
Plant
Process
Effluent Treatment
Name
Location
EPA Region
Name
Subcategory
Number of other
Products
Capacity
Production
Age
Name
Volume of Process
Effluent
Volume of Noncontact
Effluent
Type
Permit
Major Pollutants
Comments
Confidential
Inorganic
Chemicals
1976
1976
1976
40
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6.2 PROCESS WASTE SOURCES AND CURRENT TREATMENT PRACTICES
6.2.1 Data Acquisition
The information presented in this section was obtained from
a variety of published sources and the available industry
responses to the 308 Questionnaires as well as from plant visits
and interviews with industry personnel conducted by the Agency
and its contractor during the priority pollutant _screening and
verification program. The results of visits and interviews are
documented in field notebooks, interim plant visit reports, and
telephone communication records which are part of the permanent
project file.
Plant visits were particularly useful for confirming and
updating the detailed technical information contained in the 308
Questionnaire responses. The cooperative and helpful attitude on
the part of industry greatly facilitated the acquisition of
reliable operating data and meaningful sampling results.
6.2.2 Evaluation p_f Data
Each of the subcategories which were carried through the
verification sampling program as the result of the priority
pollutant levels found during screening, is the subject of an
extensive review and evaluation intended to provide the technical
basis for selecting candidate advanced treatment technologies and
developing the related base and incremental cost estimations. In
the subsections which follow, individual plant descriptions are
presented in accordance with the general format for each
subcategory:
General Process Description
Description of process reactions and unit operations.
Inventory of raw materials used.
Typical process flow diagram.
Water Use and Waste Source Inventory
Description of individual plants visited, sampled
and plant information from other sources.
Inventory of water uses for contact and noncontact
purposes.
Inventory of raw process waste water sources and
identification of sampling points.
Process waste water quality and flow data.
Solid waste generation and disposal.
Control and Treatment Practices
Description of specific treatment technologies
and operating facilities.
41
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Description of the total input to the treatment system
including sources attributed to other production
operations and noncontact water (e.g., cooling water,
etc.) .
Evaluation of Production and Waste Flow Data
Tabular summary of plant-specific data.
Waste flows per unit of production (unit waste flows)
with the range and average values.
Solid waste quantities.
Treatment chemical requirements.
Process Modifications and Technology Transfer Options
Best Management Practices (BMP)
Plant area operations and housekeeping.
Runoff control.
Solid waste handling (e.g., fugitive dust and
leachate control, etc.).
6.2.3 Model Plant and BPT Treatment System Specification
The model plant concept plays a central role in both the
development of alternative treatment system designs for priority
pollutant removal and for estimating the related internal costs
of such treatment in each subcategory. In order to be
representative of a subcategory, each set of model plant
specifications was composited from a profile data summary derived
from the available information on production and waste flow.
Based on the typically achievable waste flow rate per unit
of production/ the model plant was used as a starting point for
laying out an appropriately designed and sized BPT level waste
water treatment system. Certain assumptions had to be made
regarding the possible process variations and the specific raw
waste sources incorporated into each model and in most cases it
was found appropriate to assume that the waste flow per unit of
production did not vary over the particular range of production
capacities to be covered. Production rates were selected in most
subcategories to represent the small, mid-range and large size
plants presently in operation. Small subcategories were
represented by single mid-range production rates for the model
plants. Cost estimates were developed for each set of base level
(BPT) and advanced level (BAT/NSPS) treatment system design
specifications.
In Sections 11-25, the model plant and BPT level treatment
system descriptions and specifications for each subcategory
include the following information:
42
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Production rates and mode of operation.
Specific process type and waste sources.
Waste flow per unit of production.
Solid waste generation and handling.
Treatment chemical requirements.
If applicable, the new source model plant is also described
and the design specifications given for its waste treatment
system.
6. 2.4 Dissolved Solids _in Waste Water Effluents
Many waste treatment plants discharge final effluent into
watercourses which feed fresh water streams used as sources of
water supply by downstream agencies or industries. Groundwater
aquifers which underlie large portions of the country are tapped
to supply fresh water through wells serving public and industrial
water needs. In both cases saline wastes discharged into streams
or into unlined lagoons can significantly alter the salt content
(total dissolved solids) of the fresh water. Although Federal
regulations seldom limit the total dissolved solids or the
various ions such as chloride, sulfate, bicarbonate, and nitrate,
these constituents can be of serious concern to local water
users.
To protect the mineral quality of ground and surface waters
State and local water pollution control agencies typically
establish limits on the discharge of substances which contribute
sodium, potassium, hardness, chloride, sulfate, and conductivity,
which is a measure of total solids in solution. This restriction
can play an important part in choosing chemicals for waste
treatment. For example, alkaline precipitation can be
accomplished by using lime, which forms an insoluble calcium
sludge, or by adding caustic soda, forming a soluble sodium salt.
In choosing an acid for neutralization of alkaline wastes,
it is important to weigh the overall effects of chloride (from
hydrochloric acid) and sulfate (from sulfuric acid) , particularly
with respect to irrigational use of the receiving water.
Chemicals used in the model plant processes were selected on
the basis of best performance, including consideration of scaling
problems, which can be severe when calcium and sulfate are at
saturation levels. It may be necessary to alter the nature of
chemicals used at a specific plant, in order to meet local water
quality requirements.
43
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SECTION 7
TREATMENT AND CONTROL ALTERNATIVES FOR ADVANCED LEVEL APPLICATIONS
7.1 TREATMENT TECHNOLOGY ASSESSMENT
7.1.1 Introduction
In the inorganic chemicals industry, pollution abatement
practices vary and a wide range of treatment technologies can be
found, ranging from no treatment to the application of highly
advanced techonolgies for the removal of specific pollutants.
Until the NRDC Consent Decree, industry attention was*
primarily directed towards general pollution problems including
removal of trace metals, but not towards treatment of over 100
individual specific organic compounds now listed as priority
pollutants. Even with the classical (conventional and
nonconventional) pollutants, treatment technology has been
directed to removal down to the part per million level, whereas
now the thrust is towards part per billion level requirements.
For both these reasons, suitable BAT technologies are not in
place in the inorganic chemicals industry, and it is necessary to
look into technologies that have been applied in other industries
or developed at the laboratory or pilot plant scale specifically
for the removal of these toxic substances from industrial waste
water, and determine whether they can be adopted as viable
technological options.
A list of candidate technologies was compiled from the
literature, in-house expertise, and industry contacts. These
were evaluated with respect to:
1. Treatment effectiveness
2. Cost
3. Nonwater pollution environmental effects
4. Applications in the inorganic chemicals industry
or on other industrial wastes with similar waste
water characteristics.
44
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The anticipation that few of the organic priority pollutants
would be found in inorganic chemical wastes was justified by the
results of the analytical programs. Only one industrial
subcategory, namely, Chlor-Alkali production using graphite
anodes had potentially significant levels of organic priority
pollutants. As a result, the initial search for candidate BAT
technologies became limited to treatment technologies for the
thirteen metals, cyanide, and asbestos.
The technologies finally adopted were not new or untried
technologies since it was found that most treatment requirements
could be met by taking conventional techniques—for example,
chemical precipitation—and developing them to a higher degree of
engineering and design sophistication, so that optimum removal
efficiencies could be achieved.
The following pages describe the theoretical basis for
treatment systems adopted for BAT application.
7.1.2 Hydroxide Precipitation
Hydroxide precipitation is the most widely used technology
for removing trace metals from waste waters, with lime or caustic
soda commonly used to supply the hydroxide ions. Under suitable
conditions the metals form insoluble metal hydroxides which can
be separated from solution.
The chemistry of the process is not simple, and must be
understood for each metal. Many metals are amphoteric, the
optimum pH for precipitation varies, and organic complexes can
interfere. The simple reaction may be written as:
M++ + Ca(OH)2 = M(OH)2 + Ca++ (1)
If the pH is below the optimum for hydroxide precipitation
soluble complexes form:
M++ + OH- = M(OH)+ (2)
Since most metals have the capability of coordinating with
other ions or molecules, these simple equations assume that the
hydroxonium ion is the coordinated species. However, if organic
radicals are present, they can form chelates and mask the typical
precipitation reactions:
M++ +OH- +nR = M + (R)nOH+ (3)
45
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Such complexes may require unusual treatment to hydrolyze
them, and their presence often explains why some treatment
practices yield relatively poor results.
Assuming the absence of organic complexing agents, the
treatment levels attainable by hydroxide precipitation can be
forecast from a knowledge of the pH of the system. Figure 7-1
shows the theoretical solubility of those metals which form
insoluble hydroxides, while Table 7-1 shows the solubility
product constants. For comparison, the values for sulfides are
also given.
It is clear from the range of optimum pH's illustrated that
for waste waters containing more than one metal, no single
optimum pH exists, and problems arise at the threshold of the
alkaline range (circa pH 10) where some metals have least
solubility, while others are at the point of redissolving as an
anionic species. For successful application as a waste water
treatment technology, careful control of pH must be practiced if
the best removals are to be achieved.
In practice these problems, the solubility of metallic
hydroxides, and the tendency for fine insolubles to remain in
suspension, tend to yield effluents which will not meet ug/1
standards, and so hydroxide precipitation is often supplemented
by the use of coagulating agents to improve solids removal, or
sulfide co-precipitation to reduce ultimate solubilities.
In practice the technology uses unit process steps which are
simple, well established, and well understood by the industry.
Depending on the quantity of waste flow, the treatment can
either be a batch or continuous operation, with batch treatment
being favored when waste flows are small. In batch treatment the
equipment usually consists of two tanks, each with a capacity to
treat the total waste water volume expected during the treatment
period. These systems can be economically designed for flows up
to 50,000 gallons per day (5).
The treatment tanks serve the multiple functions of
equalizing the flow, acting as a reactor and as a settler.
During operation the waste water is stirred, and a homogeneous
sample is taken and analyzed to determine the chemical dosage
requirements. The chemicals are then added, mixed and stirred
for about 10 minutes. After the reaction has completed, the
solids are allowed to settle for a few hours. The clear liquid
is then decanted and discharged. Settled sludge is retained to
serve as a seed for crystal growth for the next batch, but must
be periodically drawn off and disposed of, usually in a chemical
landfill.
46
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10
10
10
-2
10
-4
CO
H
Q
10
-6
10
—8
10
-10
10
-12
Pb(OH)
2
Cr (OH)
Zn(OH)0
-Ag (OH)
Cu(OH)2
Ni(OH)2
Cd(OH)
0123
Figure 7-1.
45 67 8 9 10 11 12 13
Solubility of metal hydroxides and sulfides.
14
47
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TABLE 7-1 - SOLUBILITY PRODUCTS OF TRACE METALS
Metal
Cadmium, Cd
Copper, Cu
+2
Ferrous, Fe
Lead, Pb
Mercury, Hg
Nickel, Ni
Zinc, Zn
+6
Chromium (IV) ,Cr
Solubility Product
Hydroxide
13.6
18.6
15.3
16.1
25.4
14.8
15.7
8.9
Constant (1
Sulfide
26.1
35.2
16.9
26.6
52.2
25.7
25.2
°*V
. . Ethyl Xanthate
13.6
7.1
16.9
37.8
11.9
8.3
48
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A typical continuous flow treatment scheme consists of a
flash mixer, flocculator, settling unit with sludge storage tank,
and in some cases a filtration system.
The ability to separate the solids from the waste water is
important. Metallic hydroxides tend to be gelatinous and
separate poorly in gravity separators. Finely suspended solids
tend to pass out with the effluent and increase the total metal
content. Thus, improvements in precipitation applications have
been concentrated on fine solids removal, and this is reflected
in the addition of various filtration systems
flocculant aids as improved levels of treatment.
and the use of
Lime is more commonly used than caustic soda as the
hydroxide source because it is cheaper. However, if there is
sulfate ion present in the waste water, gypsum will be formed:
Ca(OH)2 + (S04)— = CaS04 + 20H-
(4)
This increases the sludge produced, may cause scaling
problems in pipelines, and may clog a dual media filter. Using
caustic soda is more expensive, but it generally eliminates the
scaling problem. Total dissolved solids in the form of sodium
salts are increased in the caustic treated waste waters. Although
low concentrations of sodium are not regarded as polluting, high
levels can make drinking water unpalatable, limit the use of
water for agriculture, and promote degradation of the structure
of arable soils. Thus, where high total dissolved solids are of
concern, lime would be the preferred neutralizing agent.
This treatment technology is widely applied in treating
industrial waste waters. Industries that are using hydroxide
precipitation include:
Inorganic Chemicals
Plating and Metal Finishing
Mining
Textiles
Steel and Iron
Non Ferrous Metal Processing and
Electronics
Better than 99 percent removal of trace metals have been
reported in the literature with final concentrations in the
treated effluents ranging from sub ppm to low ppm (see Tables 8-1
through 8-10).
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7.1.3 Ferrite Copr ec ip i. tat ion
An interesting variation on the theme of hydroxide
precipitation is a process developed in Japan for the removal of
heavy metals from acidic waste water. The process, known as
ferrite coprecipitation, has the potential for producing a
marketable residual by converting the metal ions in solution into
insoluble ferromagnetic oxides or ferrites which can be removed
magnetically or by filtration (5). The treatment is applied by
adding a ferrous salt to the metal-bearing waste water, then
neutralizing and oxidizing the complex heavy metal-ferrous
hydroxide precipitate by aeration to form the stable ferrite
coprecipitate. Particle sizes are reported to be relatively large
and sludges formed can be safely disposed of by landfilling.
Although extensive performance data have not been developed,
the information available indicates that very high removal
efficiencies can be achieved for most of the common heavy metals,
including mercury and hexavalent chromium. The method has not
been considered here as an available technology due to the lack
of sufficient information on chemical dosing requirements, energy
requirements, and performance in situations similar to those
found in the inorganic chemicals industry. It will be noted
later, in connection with the discussion of waste water treatment
in the Titanium Dioxide Subcategory for the sulfate process, that
the wastes contain considerable amounts of ferrous iron from the
processing of ilmenite ore and the current practice of
neutralization and aeration may well involve the same chemistry
as the ferrite coprecipitation process.
7.1.4 Sulfide Precipitation
The basic principle of sulfide treatment technology is
similar to that of hydroxide precipitation. Sulfide is added to
precipitate the metals as metal sulfides and the sludge formed is
separated from solution by gravity settling or filtration.
Sodium sulfide and sodium bisulfide are the two chemicals
commonly used, with the choice between these two precipitation
agents being strictly an economic consideration.
Metal sulfides form according to the following equation:
M++ + Na2S = MS + 2Na+ (5)
Figure 7-1 shows the theoretical solubility product constant
of the metals that form insoluble sulfides.
The major problem in applying sulfide precipitation
techniques is associated with the toxicity of sulfides. This
warrants both care in application and post treatment systems to
50
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remove excess sulfide. Pretreatment involves raising_the pH of
the waste stream to minimize evolution of hydrogen sulfide gas.
A recently developed and patented process to eliminate the
potential hazard of excess sulfide in the effluent and the
formation of gaseous hydrogen sulfide uses ferrous sulfide as the
sulfide source (6). The fresh ferrous sulfide is prepared by
adding sodium sulfide to ferrous sulfate. The ferrous sulfide
slurry formed is added to a waste water to supply sufficient
sulfide ions to precipitate metal sulfides which have lower
solubilities than FeS. Typical reactions are:
FeS + Cu++ = CuS + Fe++ (6)
FeS + Ni (OH)2 = Fe(OH)2 + NiS (7)
A detention time of 10-15 minutes is sufficient to allow the
reaction to go to completion (7). Ferrous sulfide itself is also
a relatively insoluble compound. Thus the sulfide ion
concentration is limited by its solubility, which amounts to
about 0.02 ppb, and the inherent problems associated with
conventional sulfide precipitation are minimized (8).
One other advantage of this process is that if chromium (VI)
is present, it will also be reduced at a normal operation pH of
8-9 and precipitate as the trivalent hydroxide.
Treatment systems for sulfide precipitation are similar to
those used for hydroxide precipitation. A continuous treatment
scheme generally consists of a pH adjustment tank, flash mixer,
flocculator, settling units with sludge storage, and a dual media
filter.
Before the addition of sodium sulfide or bisulfide the pH of
the incoming wasteflow is adjusted to pH of 7-8 in the first
reaction tank to prevent the formation of obnoxious hydrogen
sulfide gas. The chemicals are then added to the flash mixer
where they are thoroughly mixed with the waste water.
After the flash mix, the waste water passes through a
flocculating basin where the floe agglomerates and settles in the
settling unit. The overflow from the settling unit generally
passes through a filter to remove any fine precipitates. Any
excess sulfide will need to be removed before final discharge.
This can be achieved either by aeration or other chemical
oxidation techniques.
Sulfide precipitation is being practiced in the inorganic
chemicals industry, mining industry, textile industry, and
nonferrous metal processing industry. Most of the Chlor-Alkali
industry is applying this technology to remove lead or mercury
from its waste streams.
51
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Literature citations on the efficiency of sulfide
precipitationn (9, 10, 11) indicate that most results are in the
sub ppm range, and that sulfide treatment is superior to
hydroxide treatment for the removal of several trace metals. A
recent report concluded that, with no complexing agents in the
waste, the following effluent quality can be achieved (11).
Metals Concentration
Cadmium 0.01 mg/1
Copper 0.01 "
Zinc 0.01 "
Nickel 0.05 "
Chrome total 0.05 "
Adding ferrous sulfide as a polishing step to remove
residual metals appears to be a promising, economical technology.
Although there is no full-scale treatment system operating in the
inorganic chemicals industry, pilot studies on chrome pigment
waste indicate that this process is superior to sulfur dioxide
reduction followed by hydroxide precipitation (12).
7.1.5 The Xanthate Process
The use of xanthates for the removal of metals from waste
streams appears to be a new, promising technology for treating
metal-bearing waste waters. Xanthates contain functional groups
capable of forming insoluble complexes with metals, and the
sludge so formed can be separated by conventional means.
Xanthates can be generated by mixing starch or cellulose
with carbon disulfide in a caustic medium. Three types of
xanthates have been proven in bench pilot scale studies to be
effective in removing cadmium, chromium (III), copper, iron,
lead, mercury, nickel, silver and zinc from industrial waste
waters (13-20). These are:
Soluble starch xanthate with a cationic polymer,
Insoluble starch xanthate, and
Fibrous cellulose xanthate
The general removal mechanism is as follows:
2[ROCS(=S)Na] + M++ = [ROCS(=S)2M] + 2Na+ (8)
where R = starch or cellulose
52
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Unlike hydroxide precipitation, this process is reported to
be effective in removing metals over a wide pH range of 3 to 11,
with an optimum range between 7 and 9.
Brass mill waste waters, lead battery effluent, circuit
board rinse waters, electroless copper plating rinse waters,
pyrophosphate electroplating rinse waters, and copper etching
rinse waters were studied in a pilot plant with insoluble starch
xanthate as the complexing agent (20). This pilot study
demonstrated that the xanthates can either be added to a reactor
to mix with the waste waters or be applied as a precoat on a
pressure filter (20). Results of these pilot studies showed that
metals were reduced to below 50 ug/1 (ppb).
Another study indicated cellulose xanthate is as effective
as starch xanthate in removing trace metals. The following table
summarizes the result of the study with a cellulose xanthate
dosage of 90 mg/1 and a contact time of 30 minutes (18-19):
Metals
Concentration, mg/1
Influent Effluent
Cadmium
Chromium
Copper
Iron
Lead
Nickel
Zinc
1.35
0.30
1.6
3.1
3.9
2.4
1.0
0.027
0.022
0.06-0.14
0.08-0.36
0.008-0.021
0.077
0.03-0.04
This study also concluded that cellulose xanthate is
superior to starch xanthate in terms of sludge settling
characteristics, filterability, and handling.
Xanthate may also be used as a complexing
the formation of soluble anions from insoluble
hyd roxides.
agent to prevent
amphoteric metal
The xanthate process is a new technology, and the reagent
compounds are not available in commercial quantities. More
information is needed on how to feed the xanthate in continuous
flow operations. Potentially the metals can be recovered by
leaching the xanthate complex with nitric acid, but metal
recovery has not been demonstrated yet. Sludge disposal problems
may arise if the sludge complex is unstable and, if xanthates are
to be generated on site, care will be needed in handling the
hazardous carbon bisulfide.
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7.1.6 Ion Exchange
Ion exchange is a chemical reaction between the ions in
solution and the ionic sites on an exchange resin. Many natural
solids (e.g., soils, proteins, and zeolites) exhibit such
exchange characteristics. However, synthetic resins are the
predominant ones used for ion exchange applications in modern
industrial technology. These resins contain functional groups
that can react with the ions in solution. Depending on these
functional groups, the resins can be classified into:
Strongly acidic cation exchanger,
Weakly acidic cation exchanger,
Strongly basic anionic exchanger, and
Weakly basic anionic exchanger.
Cation exchangers are capable of exchanging with cations in
solution. Strongly acidic cation exchangers contain functional
groups such as sulfonates, (-S03H and -S03Na) , while weakly
acidic exchangers have functional groups derived from carboxylic
acids, (-COOH and -COONa) .
Anionic exchangers are used to exchange with the anions in
solution. In general, strongly basic exchangers contain amine
functional groups (-R3NOH and -R3NC1) , and weakly basic
exchangers contain ammonia functional groups (-NH30H and -NH3C1) .
When the functional groups are used up in the reaction, the
resins can usually be regenerated. Cationic resins can be
regenerated by sodium chloride, hydrochloric acid, sulfuric acid
or sodium hydroxide. Anionic resins are regenerated by sodium
hydroxide, ammonium hydroxide, sodium carbonate, sodium chloride,
or hydrochloric acid.
The exchanger can either be added to the waste waters in
batch operations or be packed in a fixed bed or column. Fixed bed
is by far the more effective and hence more popular. The
operation generally follows a four-step cycle: exchange
(service), backwash, regeneration, and rinse.
During the exchange step, the reaction between the ions in
solution and the ionic sites in the resin takes place as the
waste water passes down the bed. The reaction is generally
regarded as a result of electrostatic attraction (20).
Therefore, the size of the hydrated ion and the charge on the ion
are the determining factors for the exchange reaction. A
trivalent ion is attracted more strongly than a divalent ion
which is in turn attracted more strongly than a monovalent ion.
For ions with the same charge, the smaller hydrated ion is
capable of moving closer to the exchange site, and is thus
favored.
54
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with
Many synthetic resins contain functional groups that are
selective to certain metals. For example, a resin manufactured
by a European company reacts preferentially with HgCl+ ions
according to the following equation:
2RSH + Hg++ = RSHgSR + 2H+ (9)
RSH + HgCl+ = RSHgCl + H+ (10)
The exchange reaction is governed by the law of mass action.
During the reaction, the affinity of the resin for the two ions
is so great that essentially all the mercury chloride complex
formation equalibria are shifted toward the formation of Hg++ and
HgClH- which are rapidly removed. A 5 ppb residual mercury
concentration in the effluent is achieved by this process (22).
After all the exchangeable sites in the resin are used up,
the bed is backwashed by passing clean water through to loosen up
the bed and to remove any fine particulates that are trapped
inside the bed.
After the backwash cycle the resins can be regenerated
the appropriate regenerant.
RSHgCl + HC1 = RSH + HGC12 (11)
One attractive feature of the ion exchange process is that
it concentrates the metals in the regeneration step, and thus
provides a potential for their recovery. However, if recovery is
not feasible, this creates a secondary stream which needs to be
treated.
A recent study found that sodium alumino silicates
(zeolites) might be a low-cost exchanger that can be discarded
after a one-time use (22). This would eliminate the regeneration
step. On a batch study with a five-minute contact time, cadmium
and mercury were removed to below 10 ppb. Thermodynamic
considerations show this exchanger to have a high affinity for
cadmium, copper, mercury, nickel, silver, zinc, cesium, and
bar ium.
Ion exchange is a proven technology that can reduce metals
down to low concentration levels. However this technology is
used only in limited industrial pollution abatement applications
because of the high cost associated with the process.
Consequently, ion exchange has not been recommended in this
report for BAT technology.
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7.1.7 Reduction Processes
Many metals can exist in solution in several oxidation
states, and it may be necessary to convert from a higher valency
state to a lower one in order to apply a given chemical
reaction.The classic example is chromium, which as the trivalent
chromic ion will precipitate as the hydroxide in alkaline
solution, while the hexavalent chromate or dichromate ion will
not. The latter needs to be reduced if precipitation is to
occur.
Hexavalent chromium (e.g., Cr04= and Cr207=) is toxic and
soluble. The most efficient way of removing this from solution
is a two-step process of reduction followed by precipitation.
Chromium (III) is much less toxic than chromium (VI), and
forms an insoluble hydroxide which can be removed from solution
by settling and filtration.
A number of chemicals are used for the reduction of
chromium. Most common are sodium bisulfite, sodium metabisulfite,
sulfur dioxide and ferrous salts. The reduction is accomplished
readily at low pH with these reagents. Typical reduction
reactions are:
3S02 + Cr207= + 2H+ = 2Cr+++ + 3304= -t- H20 (12)
3303= + Cr207= + 8H+ = 2Cr+++ + 3304 = +4H20 (13)
6Fe++ -)- Cr207= + 14H+ = 2Cr+++ + 6Fe+++ + 7H20 (14)
The reduced chromium and the ferric ions produced in the
third equation will exist as the soluble sulfate at acid pH's. If
the pH is above 5, the reaction rate is drastically reduced, and
although dithionite will effect reduction at neutral pH's, it is
very costly and may be contraindicated.
After the reduction step, lime or caustic soda is added to
raise the pH to 8.5 - 9.0. Trivalent chromium will be
precipitated.
Cr+++ + 30H- = Cr(OH)3 (15)
The theorectical solubility limit of chromium hydroxide is
above 0.02 mg/1 (8). It is reported that applying sulfur dioxide
to a pigment waste consistantly reduces Cr(VI) and Cr(T) to 0-5
mg/1 and 15 mg/1 respectively as 30-day averages (8). By applying
ferrous sulfide to a plating waste with an initial Cr(VI)
concentration of 128 mg/1 and Cr(T) concentration of 153 mg/1, an
56
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effluent quality of less than 0.05 mg/1 of either species is
achieved (12).
A one-step precipitation-reduction process using _sodium
bisulfide is used in a dichromate plant to remove chromium from
its waste water. An effluent quality with less than 1 microgram
per liter Cr(VI), and less than 5 micrograms per liter Cr[T] was
reported , (3 ) .
One other common reduction process is the application _of
sodium borohydride to reduce metals in waste streams. Sodium
borohydride is a mild but effective reducing agent (3), and is
currently used in some chlor-alkali plants to reduce the soluble
mercury ion to metallic mercury which is removed from solution by
carbon adsorption:
4Hg++ + BH4- + 80H- = 4Hg + B(OH)4- + 4H20 (16)
A mercury level of 0.01 mg/1 in the final effluent has been
reported, (3 ) .
Sodium borohydride is also reported to be effective in
removing silver, mercury, gold, lead, and cadmium (5). However,
this technology is only being applied in limited cases, the cost
of the chemical being the major drawback. The current cost for
sodium borohydride is $16.00 per pound (23).
7.1.8 Oxidation Processes
The oxidation of organic substances is generally carried out
by thermal processes such as wet oxidation and incineration, or
by biological processes such as the activated sludge process,
trickling filters, biodiscs, and aerated lagoons.
Incineration is actually a combination of oxidation and
pyrolysis. Both involve chemical changes resulting from heat.
Oxidation involves actual reaction with oxygen, while pyrolysis
refers to rearrangement or breakdown of molecules. There are five
types of incinerators available commercially. These are rotary
kiln, multiple hearth, liquid injection, fluidized, bed and
pyrolysis, (24). A minimum temperature of 1000 degrees C. and a
residence time of two seconds is required for the reaction to
proceed. This process has been shown to be successful in reducing
pesticides to harmless modecules (25).
Wet oxidation is a process in which an aqueous waste can be
oxidized in the liquid phase in a closed, high-temperature, high-
pressure vessel. This reduces some of the problems (such as air
pollution from exhaust gas), inherent in incineration. Wet
oxidation has been used for a variety of wastes including pulping
57
-------
waste and acrylonitrile liquor (26). A 99.8 + percent reduction
of some of the priority toxic pollutants has been reported (27) .
Thermal oxidation processes are not expected to have much
application in the inorganic chemicals industry, mainly because
of the high energy cost required and the low level of organic
contamination found in the wastes.
The application of chemical oxidation to industrial wastes
is well established for cyanides, sulfite, ammonia, and other
harmful species in dilute waste streams (phenols, mercaptans,
polysulfides, etc.). Common chemicals used as oxidizing agents
included chlorine, hypochlorite, hydrogen peroxide, potassium
permanganate, ozone, and chlorine dioxide. Air and oxygen are
also used.
The most widely used chemical oxidation technology
applicable to the inorganic chemicals industry is the oxidation
of cyanide. The oxidation reaction between chlorine and cyanide
is believed to proceed as follows:
CN- + C12 = CNC1 + Cl- (17)
CNC1 + 20H- = CNO- + Cl- + H20 (18)
The formation of cyanogen chloride (CNC1) is essentially
instantaneous. The second reaction, the formation of cyanate, is
accomplished most rapidly and completely at a pH of 10 or higher,
(9, 28). A detention time of 30 minutes to two hours is usually
allowed.
The cyanates can be further decomposed into nitrogen and
carbon dioxide by excess chlorination or acid hydrolysis:
2CNO- + 40H- + 3C12 = 6C1- + 2C02 + N2 + 2H20 (19)
CNO- + 2H20 = C02 + NH3 + OH- (20)
The first reaction can be accomplished in about an hour if
the pH is adjusted to 8.0-8.5. Acid hydrolysis usually takes
place at pH 2-3 and care must be taken to avoid the liberation of
the toxic cyanogen chloride as a gas. Hydrolysis is not usually
the chosen option.
Other common chemicals used to oxidize cyanide include
sodium hypochlorite, ozone, and hydrogen peroxide. The reaction
for sodium hypochlorite is essentially the same as for
chlorination. For ozone and hydrogen peroxide, the oxidation step
proceeds as follows:
58
-------
0; CN- 02 + CNO- (21)
H;+ CN- = CNO- + H20 (22)
THvantage of using these two oxidizing reagents is_ that
no dissd solids are added to the waste water. In addition,
excess>rine is not discharged.
A nted process uses hydrogen peroxide and formaldehyde
to decoe cyanide at about 120 Deg. F. This has the advantage
of precating cadmium and zinc simultaneously (9).
Alne chlorination is currently being practiced in one
hydrogeyanide production plant. Laboratory studies in the
plant cated that the presence of ammonia in the waste water
reduces efficiency of cyanide removal. It is well known that
ammoniacts with chlorine to form chloramines:
NH HOC1 = NH2C1 + H20 (23)
NH + HOC1 = NHC12 + H20 (24)
NH+ HOC1 = NC13 + H20 (25)
Ifess chlorine is added, chloramines can be converted
into nien oxide(s):
2N+ 4HOC1 = N20 + 4HC1 + 3H20 (26)
Thquation is not exact because the final form of
nitrogexide is believed to be a mixture of nitrous oxide,
nitrogeoxide and nitric oxide.
Theatment of cyanide by chemical oxidation is currently
practicn the following industries:
Innic Chemicals (Hydrogen Cyanide Production)
Mi
Pig
Thee cyanide level after treatment is generally below
0.1 mg/) .
7.1.9 Mane Processes
_Mene processes have emerged in the last decade as a new
promisiechnology for the treatment of saline water and waste
59
-------
waters. A membrane is a semi-permeable barrier which allows the
transport of some molecules (ions) and retains others. The
driving force can either be electropotential differences
(electrodialysis) or pressure difference (reverse osmosis and
ultrafiltration). The major application of these processes has
been the desalination of brackish water and sea water. More
recently, these have also found application in a number of
industries, including:
Mining
Electroplating
Metal Finishing
Printed Circuit Board Manufacturing
Battery Manufacturing
Pulp and Paper
Food Processing
In electrodialysis, an even number of alternating anion and
cation selective membranes are placed between two electrodes.
When current is applied the anions are attracted to the anode,
and cations are attracted to the cathode. In the process of
migration, the cations pass through the cation-permeable membrane
and are blocked by the anion-permeable membrane. Likewise, the
anions pass through the anion-permeable membrane and are blocked
by the cation membrane. This results in alternating paths of
purified water and concentrated reject (Figure 7-2).
The electrodialysis membranes are made very thin and are
assembled in stacks. The flow path is the active portion of the
cells. Pretreatment to remove suspended materials is absolutely
essential. Other materials in the waste feed that may lead to
membrane fouling include high organic content, calcium sulfate,
and certain complex ions such as ZnCl- which can partially
convert the anion membrane to the cation form, with significant
loss in system performance (28).
As ionic concentration decreases, the electroconductivity of
the water also decreases, making it less efficient to remove the
remaining salt. Most operations do not produce a product water
of less than 500 mg/1 total dissolved solids.
Reverse osmosis (RO) and ultrafiltration (UF) are similar in
basic concepts. Both are pressure-driven separation processes
that employ high-flux semi-permeable membranes operating under
dynamic flow conditions (29). In contrast to electrodialysis,
these involve the transport of solvent, not solute, across the
membrane.
Osmosis is a process in which solvent from a dilute solution
is transported spontaneously across a semi-permeable membrane
into a concentrated solution. By applying enough pressure to
overcome this osmotic pressure, reverse osmosis, i.e., the
60
-------
a
8
1
6
i
?
t
©
(
i
i
— JL
/T~\
X ^
(^
r
tk.
©
a
1
I
©
<
t
~" 1
PRODUCT
WATER
I
CONCENTRATE WASTE
Figure 7-2. Electrodialysis process.
61
-------
passage of solvent from a concentrated solution to a dilute
solution through a semi-permeable membrane, occurs. The
operating pressure of reverse osmosis units is usually between
350 and 600 psi. Ultrafiltration usually operates at a much lower
pressure (5 to 100 psi). The predominant transport mechanism is
selective sieving through pores. The membrane retains high
molecular weight dissolved solids such as synthetic resins,
colloids, and proteins. The upper and lower molecular weight
limit is generally defined as 500,000 and 500 respectively.
Membranes are usually fabricated in flat sheets or tubular
forms. The most common material is cellulose acetate but other
polymers such as polyamides are also used. There are four basic
module designs: plate-and-frame, tubular, spiral-wound, and
hollow fiber. Table 7-2 is a comparison between the various
reverse osmosis modules. Membrane processes are effective in
removing (concentrating) inorganic and organic substances from a
wastestream. Usually extensive pretreatment is required among
others to reduce the suspended solids and control pH. Even so,
there are still uncertainties about the operation efficiency,
membrane lifetime, rejection specificity, and other factors. If
recovery is not feasible, the concentrated reject must be
disposed or treated by other methods. The high operation and
capital cost limits the widespread application of these
technologies. For these reasons membrane technique is not
recommended as a BAT technology for this industry.
7.1.10 Adsorption
Adsorption is a surface phenomenon in which a substance is
accumulated on the surface of another substance. Sorption of a
solute on a solid surface is widely used in pollution abatement
practices. The term "adsorbate" refers to the substance being
concentrated, and the term "adsorbent" refers to the material
that provides the surface.
Activated carbon is the prevalent adsorbent used. Both
inorganic and organic substances are known to be removed
effectively by activated carbon. Certain chlor-alkali plants are
currently using activated carbon as a polishing step to remove
mercury.
Activated carbon is made by charring basic substrates, such
as wood, coke, coal, shell, husks, etc., at 600 degrees C. in a
controlled atmosphere, where oxygen is kept low by adding carbon
dioxide or steam. This process drives out volatiles, leaving a
porous carbon lattice in an "activated" state.
Activated carbon can be obtained in powdered and granular
form. Powdered carbon is about 50-70 microns in diameter, and 90
percent should pass through a 300-mesh screen.
62
-------
TABLE 7-2
COMPARISON OF REVERSE OSMOSIS CONCEPTS
Packing
Density
(ft2/ft3)
Water Flux Water Output
at 600 psi Per Unit
(gal/ Volume(gal/
,3 /.p.i-2\ j /jro-2x
day/ft ) day/ft )
Parasitic Pressure
Sodium Losses(psi) Useful
Chloride Feed Product pH Ease of
Rejection Channel Channel Range Cleaning
Plate-and-Frame
Large tubes
Spiral
150
50
250
10
10
10
1500
500
2500
Very good
Very good
Very Good
30
50
10
30
10
50
2-8
2-8
2-8
Fair
Very good
Good to
very good
CTl
CO
Polyamide hollow
fine fibers 5000 1(400 psi) 5000
Cellulose acetate
hollow fine
fibers 2500 3(250 psi) 7500
Fair
Good
10
10
50
50
0-12 Fair
3-7 Fair
Source: Weber, Physicochemical Processes, 1972,
-------
Granular carbon is about 0.1-1 mm in diameter, this is three
times more expensive than powdered carbon. The application
involves the passage of the waste waters through a contact bed.
When the bed is exhausted, the carbon is either regenerated
or sent to landfill. It is economical for large plants to
regenerate the carbon. This can be done either by thermal
regeneration in a rotary kiln or multihearth incinerator, or by
chemical regeneration by using oxidizing agents such as hydrogen
peroxide or acids and bases.
The application of carbon adsorption has been mainly in
organic waste treatment. Recently, there are studies indicating
this is also effective in removing mercury, cadmium, cyanide,
chromium, lead, nickel, zinc, arsenic, and copper (30, 31).
An interesting development in carbon technology is its use
after the waste water is ozonized. This combination (known as
Bacteriologically Activated Carbon or BAG) has proved effective
in treating otherwise biologically inactive organic compounds.
The process involves chemical modification of the organics by the
ozone. Maintenance of an aerobic region on the carbon allows a
biologically activated film to develop and the modified organics
are further treated by a mixed process of biological oxidation
and carbon absorption.
The system has the advantage of being a potential add-on to
existing BPT systems, and should be cost effective since it has
been found that the carbon only needs regeneration at infrequent
intervals.
No industrial applications of this technology are known,
although research is under way (32) .
Bacteriologically Activated Carbon is a very attractive
potential BAT technology for the removal of organic priority
pollutants from waste streams, although no application to the
industry subcategories studied in this report was found.
7.1.11 Fluoride Removal
The conventional method of treating fluoride-bearing wastes
is to precipitate the fluoride as calcium fluoride by the
addition of lime. The reaction is:
Ca(OH)2 + 2F- = CaF2 + 20H- (27)
Using this process alone, it is difficult to remove fluoride
to below 8 mg/1 due to the solubility of calcium fluoride (9,
33). Adding alum with the lime generally improves the removal
efficiency. Fluoride ions are removed as follows:
64
-------
A1(OH)3 + F- = A1(OH)2F + OH-
A1(OH)2F + F- = A1(OH)F2 + OH-
A1(OH)F2 + F- = A1F3 + OH-
(28)
(29)
(30)
Complexed fluorides are also adsorped to some extent on the
aluminum hydroxide surface and removed in the coagulation process
(33). Large amounts of alum (5000 mg/1) are required to reduce
the fluoride concentration to below 1 ppm.
Activated alumina has been shown to be effective in removing
fluoride and arsenic in waste water, (34), and from drinking
water in municipal water treatment practice (35-38) . Typically,
the fluoride content of raw water can be reduced from about 8 to
1 ppm (38). Application of activated alumina to high fluoride
industrial wastes shows that a low ppm effluent can be achieved
(39), although high capital and operation costs generally limit
the wide application of this process.
Certain process operations used in the manufacture of
inorganic fluoride compounds involve the use of sulfuric acid and
starting materials which contain silicate or borate impurities.
This may lead to the formation of wastes containing
fl uorosul fonate, hexafluorosil icate or tetrafluoroborate complex
ions. Although tetrafluoroborate is usually a very minor
constituent and the hexafluorosilicate is readily hydolyzed in
treatment systems, the fluorosulfonate ion is fairly stable and
presents a serious problem where low levels of total fluoride are
required. The lime precipitation method is not effective in
removing the fluorosulfonate and the effectiveness of adsorption
techniques is not known.
65
-------
SECTION 8
TREATABILITY ESTIMATES AND LONG TERM DATA ANALYSIS
8.1 THE DEVELOPMENT OF TREATABILITY ESTIMATES
The review of technological treatment options applicable to
the removal of priority pollutants has lead to the conclusion
that the particular contaminants found in the raw process waste
waters of the subject industries can be effectively controlled by
the proper application of fairly well-known and demonstrated
techniques. In order to proceed from a general discussion and
description of techniques to a detailed evaluation for each
subcategory of the levels of removal that can be expected, a
summary is now presented of selected treatability data for the 13
priority metals.
The treated waste concentrations and removal efficiencies
reported in the literature are assumed to represent the best
performance characteristics that can be obtained under the
specified operating conditions. The treatment technologies
considered can thus be assigned a set of optimum conditions and
best performance estimates for removal of the particular priority
metals that are amenable to treatment. Taking each metal in
turn, Tables 8-1 through 8-10 give the initial and final
concentrations, the removal efficiencies, and the pH conditions
for different treatment technologies. The best performance
estimates for metal removal are derived from the tabulated data
and are utilized in turn as the bases for making long-term
achievable performance estimates. The sequence of analytical
steps is:
1. Review and analyze applicable performance data.
2. Estimate best performance under optimum treatment
conditions.
3. Estimate achievable performance under expected
industrial operating conditions.
The third step involves the consideration of treatment
66
-------
TABLE 8- 1. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY
ANTIMONY AND ARSENIC REMOVAL.
Treatment Technology Initial pH Removal
Concen- (%)
tration
(mg/1)
Antimony
Lime/Filter 0.6 11.5 28
Ferric chloride/Filter 0.5 6.2 65
Alum/Filter 0.6 6.4 62
Arsenic
Lime Softenin 0.2 - 85
Sulfide/Filter - 6-7
Lime (260 mg/1) /Filter 5.0 10.0 80
Lime (600 mg/1) /Filter 5.0 11.5 72
Ferric sulfate 0.05 5-7.5 90
Ferric sulfate 5.0 6.0 90
Lime/Ferric Chloride/ 3.0 10.3 98
Filter
Activated alumina 0.4-10 6.8 96-99+
Activated carbon 0.4-10 3.1-3.6 63-97
(3 mg/1)
Ferric Chloride 0.3 - 93
Ferric Chloride 0.6-0.9
Final
Concen-
tration
(mg/1)
0.4
0.2
0.2
0.03
0.05
1.0
1.4
0.005
0.5
0.05
<0.4
<4.0
0.05
<0.13
References
40
40
40
9, 10
9,10
41
41
42
.41
9,10
43
43
9,10
9,10
67
-------
TABLE 8-2. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY
BERYLLIUM AND. CADMIUM" REMOVAL -
Treatment Technology
Beryllium
Lime/Filter
Cadmium
Lime (260 mg/1) /Filter
Lime (600 mg/1) /Filter
Lime Softening
Lime/Sulfide
Ferrous Sulfide (Sulfex)
Ferrite coprecipitation/
Fil i-or
Initial
Concen-
tration
(mg/D
0.1
5.0
5.0
0.44-1.
0.3-10
4.0
240
pH
11.5
10.0
11.5
0 5-6.5
8.5-11.3
8.5-9.0
neutral
Removal
(%)
99.4
95
98
92-98
98+
99+
99+
Final References
Concen-
tration
(ng/1)
0.006 40
0.25 41
0.10 41
0.008 8
0.006 44
<0.01 7,8,11,12
0.008 5
68
-------
TABLE 8-3. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY -
COPPER REMOVAL
Treatment Technology
Lime/Filter
Lime (260 mg/1) /Filter
Line (600 mg/1) /Filter
Ferric sulfate/Filter
Lime
Lime
Alum
Lime/Sulfide
Ferrous sulfide (Sulfex)
Ferrous sulfide (Sulfex)
Ferrite coprecipitation/
F-il i-a-r-
Initial
Concen-
tration
(mg/D
3.2
5.0
5.0
5.0
10-20
3.0
3.0
50-130
3.2
4.0
pH
8.5-9.0
10.0
11.5
6.0
>8.5
9.5
6.5-7.0
5.0-6.5
8.5-9.0
8.5-9.0
-
Removal
(%)
98
92
91
95
90
93
93
-
99
99+
99+
Final
Concen-
tration
(mg/1)
0.07
0.4
0.5
0.3
1-2
0.2
0.2
<0.5
0.02
0.01
0.01
References
8
41
41
41
9,10
45
45
44
8, 12
7,8,U
5
69
-------
TABLE
8-4. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY
CHROMIUM III AND CHROMIUM VI .REMOVAL
Treatment Technology
Chromium III
Lime (260 mg/1) /Filter
Lime (600 mg/1) /Filter
Reduc tion/Lime
Reduction/Lime
Lime Softening
Lime/Filter
Lime
Lime
Ferrite coprecipitation/
Filter
Ferric sulf ate
Ferric sulfate/Filter
Chromium VI
Activated carbon
(pulverized, Pitts-
burgh type RC)
Same as above
Activated carbon
(granular)
Ferrite coprecipitation
Sulfur dioxide reduction
Bisulfite reduction
Initial pH Removal
Concen- (%)
tration
(mg/1)
5.0 10.0 98
5.0 11.5 98
140 (as 7-8
Cr VI)
1300 (as 7-8
Cr VI)
10.6-11.3 98+
7-9
15 9.5
3.2 9.5
10 - -
6.5-9.3 98+
5.0 - 99
10 3.0 85
10 2.0 96
3 6.0 98
0.5
- - -
Final
Concen-
tration
(mg/1)
0.1
0.1
1.0
0.06 CrIII
0.15
0.05
0.1
< 0.1
<0.01
-
0.05
1.5
0.4
0.05
not
detectable
0.01-0 ,1
0.05-1.0
References
41
41
9,10
3,9,10
46
47
45
45
5
46
41
48
48
41
5
9,10
9,10
70
-------
TABLE 8-5. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY
LEAD REMOVAL
Treatment Technology
Lime/filter
Lime (260 mg/1) /Filter
Lime (600 mg/1) /Filter
Ferrous sulf ate/Filter
Sodium hydroxide/Filter
Sodium carbonate/Filter
Sodium carbonate/Filter
Ferrous sulfide (Sulf ex)
Ferrite coprecipitation/
Initial
Concen-
tration
(mg/1)
189
5.0
5.0
5.0
1700
1260
5.0
189
475
pH
8.5-9.0
10.0
11.5
6.0
10.5
10.1
9.0-9.5
8.5-9.0
-
Removal
(%)
99.9
98.5
98.0
98.5
99+
99+
99+
99.9
99.9
Final
Concen-
tration
(mg/1)
0.1
0.075
0.10
0.075
0.60
0.60
0.01-0.03
0.1
0.01
References
5
41
41
41
49
49
9,10
8,12
5
71
-------
TABLE 8-6. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY -
MERCURY II REMOVAL
Treatment Technology
Sulfide
Sulfide
Sulfide/Filter
Sulfide/Filter
Sulfide/Filter
Ferrite coprecipitation/
Filter
Activated Carbon
Activated Carbon/Alum
Activated Carbon
Initial pH Removal
Concen- (%)
tration
Crag/1)
0.3-50.0
10.0 10.0 96.4
16.0 5.5 99
36.0 4.0 99.8
0.3-6.0 5.8-8.0 87-99.2
6.0-7.4 - 99.9
0.01-0.05
0.02-0.03
0.06-0.09
Final References
Concen-
tration
(mg/1)
0.01-0.12
1.8
0.04
0.06
0.01-0.125
0.001-0.005
<0.0005
0.009
0.006
9,10
50
50
50
50
5
9, 10
46
50
72
-------
TABLE 8-7. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY
NICKEL REMOVAL
Treatment Technology
Lime
Lime (260 mg/1) /Filter
Lime (600 mg/1) /Filter
Caustic Soda/Filter
Ferrous sulf ide (Sulfex)
Initial
Concen-
tration
(mg/1)
75
5.0
5.0
-
75
pH
8.5-9.0
10.0
11.5
11.0
8.5-9.0
Removal Final
(%) Concen-
tration
(mg/1)
98 1.5
94 0.3
97 0.15
0.3
99.9 <0.05
References
8
41
41
49
8,11, 12
73
-------
TABLE 8*8. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY -
SILVER REMOVAL
Treatment Technology
Sodium hydroxide
Ferric sulfate (30 mg/1)
Lime Softening
Chloride precipitation
(alkaline chlorination
in the presence of
cyanide)
Ferric chloride/Filter
Sulf ide precipitation
Initial
Concen-
tration
(mg/1)
54
0.15
0.15
105-250
0.5
-
pH Removal
(%)
9.0 72
6-9 72-83
9.0-11.5 80-93
97+
6.2 98.2
5-11 very high
Final
Concen-
tration
(rag/1)
15
0.03-0.04
0.01-0.03
1.0-3.5
0.04
—
References
13
46
46
9,
40
9,
10
10
74
-------
TABLE 8-9. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY
SELENIUM AND THALLIUM' REMOVAL
Treatment Technology
Selenium
Ferric chloride/Filter
Ferric chloride/Filter
Alum/Filter
Ferric sulfate
Ferric sulfate
Lime/Filter
Lime/Filter
Thallium
Lime/Filter
Ferric chloride/Filter
Alum/Filter
Initial
Concen-
tration
(mg/D
0.1
0.05
0.5
0.10
0.10
0.5
0.06
0.5
0.6
0.6
pH
6.2
6.2
6.4
5.5
7.0
11.5
11.5
11.5
6.2
6.4
Removal
(%)
75
80
48
82
75
35
38
60
30
31
Final
Concen-
tration
(mg/1)
0.03
0.01
0.26
0.02
0.03
0.3
0,04
0.2
0.4
0.4
References
40
40
40
51
51
40
40
40
40
40
75
-------
TABLE 8-10. WASTE WATER TREATMENT OPTIONS AND PERFORMANCE DATA SUMMARY -
ZINC REMOVAL
Treatment Technology
Lime/Filter
Lime (260 mg/1) /Filter
Lime (600 mg/1) /Filter
Lime/Filter
Sodium hydroxide
Sulfide
Ferrous sulfide (Sulfex)
Ferrite coprecipitation
Initial pH
Concen-
tration
(n*g/D
3.6 8.5-9.0
5.0 10.0
5.0 11.5
16
33 9.0
42
3.6 8.5-9.0
18
Removal
(%)
93
84
77
-
97
97
99+
99+
Final
Concen-
tration
(mg/1)
0.25
0.8
1.2
0.02-0.23
1.0
1.2
0.01-0.02
0.02
References
8
41
41
5
13
5
8, 11, 12
5
76
-------
system variables under full-scale operating conditions in
industrial situations where the design objective would be the
simultaneous removal of several waste load constituents. Each
industry designs for maximum removal and/or recovery of the major
process-related waste substances and utilizes an appropriate
technology which is both reliable and cost effective. Optimum
treatment conditions for the removal of a particular pollutant
can rarely be achieved consistently and any given set of
conditions will be somewhat less than optimum for most, if not
all, of the treatable constituents. In any well-operated
production facility the normal variations in product rates, raw
material quality, the desired product mix in some cases, and
contact water use requirements may cause severe hydraulic and
pollutant load input excursions which at best can be moderated by
effective equalization in the treatment system. This is
considerably less of a problem in batch treatment than with a
continuously operating system. The latter requires continuous
feedback monitoring for pH control and chemical dosage in order
to maintain the effluent quality within acceptable limits for a
number of parameters. Under these conditions, the 30-day
averages derived from the actual treated effluent monitoring data
(NPDES, etc.) would equate to what has been identified in Step 3
above as the estimated 30-day achievable performance using the
same general treatment technology.
The estimated long term achievable performance values are
presented in Table 8-11.
A statistical evaluation of long-term monitoring data is
described below and the results are presented in Appendix A where
various derivative quantities such as long term averages and
standard deviations are tabulated and the bases for formulating
the variability factors applicable to each subcategory are
explained in detail.
For each nonexcluded subcategory, a tabular presentation of
the logic used to develop effluent limitations is given, based on
performance estimates for 30-day average concentrations for
specific pollutants. When available, these concentrations are
based on industry monitoring data. When long-term data are not
available from industry, as is the case with most priority
pollutants, achievable concentrations are based on the
treatability of these pollutants as discussed in Section 8 and
summarized in Table 8-11.
Variability factors applied to these concentrations for the
development of monthly average and daily maximum limitations are
based on statistical analysis of long-term data as presented
below and in Appendix A. In many cases, due to the limited
amount of long-term data available, variability factors observed
in one subcategory are applied in other subcategories where
similar treatment technologies are practiced.
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TABLE 8-11. ESTIMATED ACHIEVABLE 30-DAY AVERAGES FOR THE APPLIED
TECHNOLOGIES
Final Concentrations (mg/1)
Ferrite
Lime Lime Sulf ide Coprecip- Soda Ash Soda Ash Alum
Settling Filter Filter itation Settling Filter
Filter
Antimony, Sb 0.8-1.5 0.4-0.8
Arsenic V 0.5-1.0 0.1-0.5 0.05-0.1
Beryllium, Be 0. 1-0.5 0.01-0.1
Cadmium, Cd 0.1-0.5 0.05-0.1 0.01-0.1 <0.05
Copper, Cu 0.5-1.0 0.1-0.7 0.05-0.5 <0.05
Chromium III, 0. 1-0. 5 0.05-0.5 <0.05
Cr+3
Lead, Pb 0.5-1.0 0.1-0.8 0.1-0.4 <0.05 0.4-0.8 0.1-0.6
Mercury II , 0. 01-0.05<0. 01
Hg
Nickel, Ni 0.5-1.0 0.1-0.5 0.1-0.5
Silver, Ag 0.4-0.8 0.2-0.4 0.05-0.2
Selenium, Se 0.2-1.0 0.1-0.5
Thallium, Tl 0.2-1.0 0.1-0.5 0.2-0.5
Zinc, Zn 0.5-1.0 0.4-0.8 0.2-0.5 0.2-0.5
Fluoride (Free),25 15
F
78
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TABLE 8-11 continued
Final Concentrations (mg/1)
Ferric Activated S02 Bisulfite Lime/FeCl2 Akaline
Chloride Carbon Reduction Reduction Filter Chlor-
ination
Arsenic V, As 0.05-0.5 0.3 0.02-0.1
Chromium VI, 0.1 0.05-0.1 0.05-0.5
Cr+6
Mercury II, 0.01
Hg
Silver, Ag 0.05-0. 1
Selenium, Se 0.05-0.1
Thallium, Tl 0.7
Cyanide (Free), 0105
CNA ' '
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8.2 THE USE OF HISTORICAL POLLUTANT DATA
8.2.1 Determination o_f Enforcement Guidelines Based Upon
Historical Performance
In cases where there has been long term monitoring of the
pollution levels in the effluent stream discharged by a plant, it
is possible to assess plant pollution performance through
analysis of historical data that has been collected for this
purpose. The appropriateness of standards constructed from data
collected from a single plant performance is, of course,
dependent on the plant's current performance in relation to the
performance of other plants in the manufacturing subcategory. As
economically feasible alternative waste treatment technologies
become available, pollutant discharge guidelines need be reviewed
and revised to reflect these advances. Recommendations for using
methods presented in this section should, therefore, be construed
as useful for "monitoring" situations rather than those which
require "normative" ones. These methods serve to insure that
proper maintenance of treatment facilities preserves the
capability to effectively reduce waste pollutant levels.
Statistical analysis of historical monitoring data is
required to assess a plant's ability to discharge within set
guidelines. To perform this analysis certain assumptions must be
made regarding the nature of applicable statistical or
probabilistic models, the constancy of the operation of the
treatment facility, and the quality of the monitoring methods.
Assumptions made in this report are outlined in the following
sections.
Assumptions Concerning Daily Pollutant Level Measurements
In the formulation and calculation of the following
performance standards, individual sample measurements of
pollutant levels were assumed to follow the lognormal
distribution, a well known and generally accepted statistical
probability model used in pollution analyses. It follows, then,
that the logarithms of these measurements follow a normal
probability model. It was also assumed that monitoring at a
given plant was conducted responsibly and in such a way that
resulting measurements can be considered statistically
independent and amenable to standard statistical procedures. A
final assumption was that treatment facilities and monitoring
techniques had remained substantially constant throughout the
monitoring period. Summaries of the data extracted from 308
Questionnaires are presented in the tables Addendum A. In these
tables, the minima (min) , arithmetic averages (aver) , maxima
(max), and standard deviations, (st dev), were computed directly
from the data using standard statistical formulae. No
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logarithmic transformations were necessary to accomplish the
calculations. The tables are representative of currently
achieved pollutant discharge performance levels in the several
plants presented.
8.2.2 Assumptions Concerning 30-Day Average Pollutant Level
Measurements.
While individual pollution level measurements should be
assumed lognormally distributed, that same assumption is not
appropriate when studying 30 day averages. These averages are
generally not distributed as lognormal quantities. However, if,
averages are taken over a reasonably large number of days, a
statistical principle, the "Central Limit Theorem", states that
procedures which are appropriate for a normal (not lognormal)
probability model should be applied. Therefore, the methods used
in computing historical performance characteristics for 30-day
averages differ somewhat from those used for daily samples in
that the coefficient of variation* as defined below, is the
primary determinant of the variability factor for the normal
probability model.
[* Coefficient of variation is defined as the ratio of a
statistical populations standard deviation to its average value.]
8.2.3 Variability Factor for Daily Samples.
Since 30 day average and daily sample data require different
approaches, separate presentation of their methods are given
here. Variability factors for daily observations are presented
initially. In the analysis of daily data the inherent
variability of measured pollutant levels in the effluent stream
from inorganic chemical manufacturing processes must be
incorporated in calculating upper limits for daily pollutant
discharge levels. Even well treated and controlled plants may
experience some days when an atypically high level of pollutant
discharge is present in their waste stream. Such high variations
may be due to a variety of factors, such as short term
maladjustments in treatment facilities, variation in flow or
pollutant load, or changes in the influent stream. To allow for
this variability, performance standards must necessarily be set
above the plant's long term average performance and occasional,
infrequent excessive discharges permitted. Since pollutant
discharge is often expressed in terms of average level, it is
convenient to describe standards of performance and allow
variability in term of multiples of this average. Such a method
of computing standards as functions of multiples of average level
performance is explained below. The ratio of the pollutant
standard level to the estimated long term average is commonly
called the "variability factor". This factor is especially
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useful with lognormally distributed pollutant levels because its
value depends upon the expected number of excessive discharge
periods and upon the day to day variation of the process, but is
independent of the long term average, so that variations in
average discharge do not affect its value.
For a lognormal population, the relationship between the
pollutant standards, P, and the estimated long term average, A,
can be shown to be:
ln(P/A) = S(Z-0.5S)
where
1) S is the estimated standard deviation
of the logarithms of pollutant level measurements.
In the calculations which follow, S is computed by the
statistical procedure known as the "method of moments".
This procedure requires that S be computed as the
square root of the natural logarithm of one plus
the square of the estimated coefficient of variation.
and
2) Z is a factor derived from the standard normal
distribution. Z is chosen to give enforcement
limitations which provide a balance between appropriate
consideration of day to day variation in a properly
operating plant and the necessity to insure that a
plant is operating properly. If the Z value is too high,
a treatment facility may deteriorate appreciably without
triggering an enforcement action. If it is too low,
unneeded enforcement actions will occur.
3) "In" represents the natural logarithm (base e) of a
numerical quantity.
The value chosen for Z is very highly dependent on the
conditions which trigger an enforcement action and the nature of
the surveillance (monitoring) of a plant. If there is daily
sampling, and if an enforcement action is triggered by frequent
violations, and if "frequent violations" are "... those which
occur more than once in any four quarters.", then a choice of Z
= 2.78 is appropriate. Using the limitations computed for this
value of Z, one expects that only one violation will occur among
365 daily measurements, that is, one expects that 364/365ths or
99.73% of a years measurements will not exceed the limitation. An
alternative criterion for which one expects that only 1% (5%) of
the daily observations of a properly operating plant exceed the
limitation would be to choose Z = 2.33 (Z = 1.64).
8.2.4 Variability Factor for 30-Day Averages
Using averages of 30 lognormally distributed measurements to
ascertain conformance to effluent limitations introduces
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complications in the computation of variability factors. As has
been noted before, the statistical distribution of 30 day (or
"calendar monthly") averages is the well known normal
distribution. The variability factor for this distribution is a
different function of the underlying coefficient of variation
than previously given for daily maxima.
For the normal distribution appropriate to 30 day averages,
the relationship between the discharge standard, P, and the
estimated long term average, A, may be demonstrated to be:
P/A = 1.00 + Z(CV)
where
1) Z is determined in the same manner as for daily data
above except that Z values differ because only 11 of 12
measurements in one year must meet standards,
and
2) CV is the estimated coefficient of variation computed
from the sample of historical monthly averages;
i.e. CV = S/A. In this case A and S are computed directly
from the monthly averages. No logarithmic transformations
are involved.
The results of computations on historical data under the
assumptions outlined above are presented in Appendix A. The
variability factors for daily maxima are computed using A =
average of daily measurements and, as the method of moments
stipulates, S = the square root of the natural logarithm of one
plus the square of the estimated coefficient of variation of the
untransformed (not logarithmic) daily measurements. The
variability factors for monthly averages are computed using A =
average monthly average and S = standard deviation of monthly
averages (untransformed).
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SECTION 9
TREATMENT TECHNOLOGY APPLICATIONS
FOR PRIORITY POLLUTANT REMOVAL
9.1 SELECTION OF POLLUTANTS TO BE CONTROLLED
In order to determine which priority pollutants, if any, may
require effluent limitations, the pollutants observed in each
subcategory were evaluated with regard to their treatability and
potential environmental significance on the basis of the raw
waste concentrations and mass loadings found during screening and
verification.
Group 1 - Those metals which appear at concentration levels that
are readily treatable using available technology and
which have environmentally significant mass emission
rates.
Group 2 - Potentially significant metals observed in the
subcategory
Table 9-1 presents the significant priority pollutant metals
found in each subcategory, and divides these metals into two
groups. In general, those metals occuring in the first group are
of prime concern and may require regulation, while those
occurring in the second group are of somewhate less concern and
are not expected to require regulation.
9.2 APPLICATION OF
ALTERNATIVES
ADVANCED LEVEL TREATMENT AND CONTROL
9.2.1 General Design Objectives
Beginning with Section 11 of this document, the selection
and application of priority pollutant treatment and control
technology for model plant systems for each of the subcategories
proposed for regulation are described. Level 1 represents
existing BPT treatment systems and the advanced levels (Level 2,
3, etc.) are the selected technologies for step-wise improvements
in priority pollutant removal over that achieved by the BPT
system. Flow diagrams show BPT components as a starting point
for advanced level treatment additions and incremental cost
estimates.
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TABLE 9-1. PRIORITIZATION OF POLLUTANT METALS FOUND IN EACH SUBCATEGOKY
SUBCATEGORY
Group 1
Group 2
Chlorine-diaphragm cell
Chlorine-mercury cell
Hydrofluoric Acid
Titanium Dioxide -
Chloride Process
Titanium Dioxide -
Sulfate Process
Aluminum Fluoride
Antimony
Arsenic
Chromium
Copper
Lead
Nickel
Arsenic
Mercury
Thallium
Zinc
Arsenic
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Zinc
Chromium
Lead
Nickel
Zinc
Arsenic
Cadmium
Chromium
Copper
Lead
Nickel
Thallium
Zinc
Copper
Selenium
Cadmium
Mercury
Selenium
Thallium
Zinc
Antimony
Cadmium
Chromium
Copper
Lead
Nickel
Silver
Antimony
Cadmium
Thallium
Antimony
Arsenic
Cadmium
Chromium
Mercury
Nickel
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TABLE 9-1 - continued
SUBCATEGORY
Group 1
Group 2
Chrome Pigments
Hydrogen Cyanide
Sodium Dichromate
Copper Sulfate
Nickel Sulfate
Antimony
Cadmium
Chromium
Cyanide
Lead
Nickel
Zinc
Cyanide
Chromium
Nickel
Zinc
Arsenic
Cadmium
Copper
Nickel
Zinc
Nickel
Sodium Bisulfite
Zinc
Arsenic
Copper
Selenium
Silver
Antimony
Lead
Cadmium
Chromium
Copper
Lead
Mercury
Selenium
Thallium
Antimony
Cadmium
Chromium
Copper
Lead
Mercury
Nickel
36
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For both existing and new sources, the advanced level
technology options are selected as candidates for BAT with
priority pollutant removal as the primary objective. Although
the advanced level systems chosen also give improved performance
over the Level 1 (BPT) systems for the removal of conventional
and nonconventional pollutants, this is regarded as a secondary
design objective.
9.2.2 Pretreatment Technology
Since untreated heavy metal ions will usually pass through
the treatment provided in a typical POTW, or will be precipitated
with the POTW solid residue, pretreatment of wastes containing
significant amounts of heavy metals is necessary- As a general
rule, alkaline precipitation, followed by settling and removal of
the solids, will suffice. In certain subcategories, such as the
chlorine industry, specific treatment will be required for highly
critical constituents (mercury, lead, chlorinated organics and
asbestos) . Normally the Level 2 model treatment processes shown
in the following subsections will be appropriate for pretreatment
prior to discharge to a POTW.
9.2.3 New Source Performance Standards
In only one subcategory, hydrofluoric acid, is a technology
proposed for new sources. For the remaining subcategories, the
Level 2 model treatment process is considered appropriate
technology for new sources.
9.3 ESTIMATED ACHIEVABLE PERFORMANCE CHARACTERISTICS FOR ADVANCED
LEVEL APPLICATIONS
Advanced level control and treatment alternatives for
reduction of pollutant discharges and their applicability to each
subcategory are presented in the sections dealing with individual
products. With few exceptions, these alternatives were selected
specifically for removal of priority pollutants and were designed
for end-of-pipe treatment.
Treatment technologies practiced outside the industry are
recommended when appropriate and, in most cases, apply to the
removal of priority pollutant metals. The estimated 30-day
average treatability levels (Sections 8, Table 8-11), long term
data parameters, and the screening and verification results are
all utilized in the development of estimated performance
characteristics for the recommended treatment applications in
each subcategory.
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9.3.1 Advanced Level Removal of BPT Pollutants
Performance estimates for these systems, when possible, were
based on effluent quality achieved at plants currently practicing
thes technologies. However, in most cases, the advanced levels
are not currently being practiced within the specific subcategory
of concern, and performance information from other appropriate
sources is necessarily utilized.
When established waste water treatment practices, such as
clarification or filtration, form a part of advanced treatment
alternatives, the specified achievable effluent quality has been
based on concentrations accepted as achievable through proper
design and control. The prime example of this is suspended
solids reduction by filtration.
9.3.2 Advanced Level Removal of Priority Pollutants
Performance estimates for priority pollutants were also
based, when possible, on effluent quality achieved at plants
currently practicing these technologies. However, in most
subcategories, priority pollutant analyses are not conducted
unless a specific pollutant is regulated and requires monitoring.
Where transfer of technology is applied as a treatment
alternative, performance estimates for priority pollutant
removals were based on the demonstrated performances in other
industries while incorporating allowances for specific
differences in process waste characteristics and operating
conditions. Statistically derived long-term monitoring data
parameters were described in Section 8 and are compiled in
tabular form in Appendix A. The screening and verification data
are used to supplement the available long-term data applied to
each subcategory. A judgment is made as to whether the screening
and verification data represent a well performing system or one
which is not performing at its technological potential. For a
well performing system, the data are regarded as representative
of 30-day averages and are compared with the estimated
treatability ranges from Table 8-11, as well as the 30-day
averages developed from the long-term data. In this manner, the
performance estimates for each pollutant, at each treatment level
for the nonexcluded subcategories, are developed and presented in
tabular summaries. By starting with the estimated achievable
30-day averages, the specific variability factor ratio derived
for each pollutant is used to estimate the daily maximum values.
The model plant waste flow per unit of production is then
taken to calculate the estimated mass emission values of the
30-day average and daily maximum limits for each pollutant to be
controlled.
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SECTION 10
COSTS OF TREATMENT AND CONTROL SYSTEMS
10.1 INTRODUCTION
10.1.1 Purpose of Cost Data
More complex treatment methods and higher levels of
pollutant removal are reflected in increased costs of equipment,
energy, labor and chemicals. At some point, the increasing costs
of treatment will outweigh the benefits of such treatment.
Therefore, it is important that for each subcategory the Agency
know the base cost and he incremental costs of each level of
treatment which it might prescribe. These "options" of internal
costs, which are the industry's annual costs of providing the
necessary waste treatment, will result in related increases in
product costs, which are termed external costs. Thus annual
costs of waste treatment are expressed in terms of dollars per
unit of annual production of the principal product.
Because plant visits revealed very few t
serving a single product manufacturing line, it
to seek actual waste treatment facilities which
real models for estimating purposes. Accordingly
were taken from similar construction projects by
and from unit process equipment costs assembled
other commercial sources. Because the model costs
range of climate, material sources and labor
should be considered as preliminary estimates
minus 15 to 25 percent.
reatment plants
was not feasible
could serve as
, the cost data
the contractor,
from vendors and
apply to a wide
conditions they
within plus or
Actual costs incurred by individual plants may be more or
less than the presented model plant costs. The major causes of
variability are:
Waste water treatment combined with the treatment of
other product effluents.
Site dependent conditions, as reflected in piping
lengths, climate, land availability, water and power
supply and the location of the points of final
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discharge and solids disposal.
3. Material (reagent) costs, due to variation in
availability and distance from the source.
The construction costs are based on the Engineering News
Record Construction Index for July 1978 (ENRCI=2800) , and other
costs are expressed in mid-1978 dollars.
10.1.2 General Approach
Since few single product waste treatment plants were
available for detailed study, the costs presented in this section
are based on model plants which closely resemble the types and
capacities of waste treatment facilities needed for each separate
product subcategory. The model plant selections are based on
review of Section 308 Questionnaire responses, plant visits,
development documents, contacts with the industries to verify
treatment practices and to obtain data on size, waste water flow,
and solid waste disposal systems. Thus, each model is
synthesized from actual data as a typical plant in its
subcategory with a level of waste treatment equivalent to BPT.
Variations in treatment plant capacity are accounted for by
selecting sets of models which represent the range of existing
production plant capacities in the subcategory; large, medium and
small. Thus the model plants are not set up as exemplary plants,
but as typical plants of adequate design which represent the
range of plants and treatment facilities found in the
subcategory.
10.1.3 Cost References and Rationale
Cost information contained in this report was obtained
directly from industry, engineering firms, equipment suppliers
and current experience of the contractor. Whenever possible,
costs are based on actual industrial installations or engineering
estimates for projected facilities as supplied by industries
consulted during the study. In the absence of such information,
cost estimates have been developed from either current costs for
similar waste treatment installations at plants making other
inorganic chemicals or from general cost estimates for specific
treatment technologies.
Treatment costs are based on model production plant
characteristics which determine the treatment processes selected
for each operation. Under set effluent limitations, treatment
costs are primarily functions of the pollutant load (i.e., kg/kkg
of product), waste water flow rate (i.e., cubic meters/day).
Available data indicate that both pollutant loads and flow rates
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can vary significantly among plants manufacturing the same
product.
10.1.4 Definition of Levels of Treatment and Control Cost
Development
For the purpose of establishing the base level treatment
costs, each industry is assumed to be practicing Best Practicable
Control Technology Currently Available (BPT), which the EPA
Effluent Limitations Guidelines required by 1977 for certain
pollutants (conventional and nonconventional, as well as some of
the priority toxic pollutants) specified for each subcategory.
The investment costs and annual costs of such BPT systems are
shown in this report as the base level or Level 1. This level of
treatment may also provide incidental removal of additional
priority toxic pollutants not previously specified in the
regulations.
The advanced treatment levels (Level 2, Level 3, etc=) are
aimed primarily at reduction of priority toxic pollutants to
levels considered acceptable for July 1, 1984, performance,
utilizing Best Available Technology Economically Achievable (BAT)
at incremental investment and annual costs beyond those shown for
Level 1. For example, for Level 3 treatment, the incremental cost
as given in the table is directly added to base or 1st Level cost
to obtain the total cost of the treatment system. The addition
of the Level 2 incremental cost is not required to obtain the
Level 3 total. The waste water treatment flow diagram for Levels
2, 3, etc., as given under Section 8 of this report, includes the
flow diagram for base or Level 1 of treatment. This is because
increment levels of treatment are always added to the 1st level
of treatment.
10.1.5 Treatment and Disposal Rationale Applied to Cost
Development
The following assumptions are employed in the cost
development:
1. All noncontact cooling water is excluded from treatment
(and treatment costs) provided that no pollutants are
introduced.
2. Water treatment, cooling tower and boiler blowdown discharges
are not considered process waste water unless such flows
contain significant amounts of pollutants.
3. Sanitary sewage flow is excluded.
4. The plants are assumed to operate 24-hours per day, 350 days
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a year, except where noted otherwise.
5. Manufacturing plants are assumed to be single product plants.
6. The inorganic chemical industry has generally found and
extensively uses in-plant control techniques such as
in-process abatement measures, housekeeping practices, and
recycling of process waste waters to recover valuable
materials or use these materials as feed for other
by-products. Segregation of uncontaminated cooling and
other waters prior to treatment and/or disposal, and similar
other measures can contribute to waste load reduction. All
such costs have not been included in the cost estimates.
7. Excluded from the estimates are any costs associated with
permits, reports or hearings required by regulatory agencies.
10.1.6 Expression of Costs
j*
Investment costs for Level 1 treatment systems are expressed
in mid-1978 dollars to construct base level facilities for each
single product manufacturing subcategory at various production
rates.
Similarly, operation, maintenance and amortization of the
investment are expressed as base level annual costs for Level 1
and as incremental annual costs for Level 2 and above. Where a
single product plant produces more than one waste stream
requiring treatment, the respective investment and annual costs
are the combined costs of all treatment.
Total annual costs per metric ton of product are shown in
the summaries for each product subcategory.
Direct Investment Costs for Land and Facilities
Types of direct investment costs for waste treatment
facilities and criteria for estimating major components of the
model plants are contained in the following subsections:
Construction costs - Construction costs, including site
preparation, grading, enclosures, buildings, foundations,
earthwork, roads, paving and concrete.
The costs of constructing lagoons can vary widely, depending
on local topographic and soil conditions. The required areas of
lagoons and settling ponds and their consequent costs are
developed as a function of volume (capacity). It is assumed that
reasonably level sites are available, consisting of sandy loam
with high clay content and no large rocks or rock formations.
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It is assumed that two rectangular lagoons are furnished in
parallel, with one common dike to permit alternate dewatering for
sludge removal by the clamshell method. Using balanced cuts and
fills, earth dikes with 2:1 slopes provide liquid depths from
three to five meters. Earth moving costs are significantly
affected by site conditions and quantities. To express these
variations for a range of sizes at three depths, the cost of
clearing, excavation, dewatering, compaction, finish grading,
riprap and associated indirect expenses for earthen lagoon were
plotted against liquid volume. Piping, valving and dike roads
not included are added separately in the cost summaries. Lagoons
are unlined unless the contents are highly pollutional or acidic.
The liner material employed for impervious lagoons is Hypalon.
The installed cost of the liner is $11.00 per square meter ($9.20
per square yard), which includes the trenching and backfilling
necessary for anchoring the liner. In some subcategories, in
place of Hypalon, clay lining has been used at a cost of $5.40
per square meter ($0.50 per square foot) .
Costs of buildings may vary from $25.00 to $45.00 per square
foot. For the purpose of this study, building cost is estimated
at $377.00 per square meter ($35.00 per square foot).
Concrete construction for miscellaneous work varies from
$260.00 to $785.00 per cubic meter ($200.00 to $600.00 per cubic
yard). For foundations and flat slabs, concrete has been
estimated at $395.00 per cubic meter ($300.00 per cubic yard) in
place. Asphalt paving which has been used on lagoon dikes and
for miscellaneous roads, is installed at a cost of $9.70 per
square meter ($0.90 per square foot). A width of three meters is
generally assumed.
Equipment costs - Depending upon the method of treatment,
equipment for waste water treatment consists of a combination of
items such as pumps, aerators, chemical feed systems, agitators,
flocculant feed systems, tanks, clarifiers, thickeners, filters,
etc. Cost tables for these items were developed from vendors'
quotations on a range of sizes, capacities and motor horsepowers.
Except for large size tanks and chemical storage bins, the cost
represents packaged, factory-assembled units. Mechanical
components are generally skid mounted, prepiped and prewired; and
include associated pumps, meters and instrumentation. Critical
equipment is assumed to be installed in a weather proof
structure. Chemical storage, feeders and feedback equipment
include such items as probes, instruments, controls,
transmitters, valves, dust filters and accessories. Bulk
chemical storage bins are designed to hold a standard bulk truck
load, plus five days needs, between ordering and delivery.
Critical pumps are furnished in duplicate and when clarifiers are
used, the flow is split between two units, permitting one to be
bypassed for repairs. Single units are used for small flows,
batch treatment and intermittent service.
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Installation cost - Installation is defined to include all
services,activities, and miscellaneous material necessary to
implement the described waste water treatment and control
systems, including piping, fittings, and electrical work. Many
factors can impact the cost of installing equipment modules.
These include wage rates, manpower availability, whether the job
is performed by outside contractors or regular employees, new
construction versus modification of existing systems, and
site-dependent conditions (e.g., the availability of sufficient
electrical service) . In these estimates, installation costs were
chosen for each application, based upon average site conditions
and taking into consideration the complexity of the system being
installed. An appropriate cost is allowed for interconnecting
piping, power circuits and controls.
Monitoring equipment - In this report, it is assumed that
monitoring equipmentwTTl be installed at the treated effluent
discharge point. It will consist of an indicating, integrating
and recording type flow meter, pH meter with sensor and recorder,
alarms and controls and an automatic sampler.
Land - Land availability and cost of land can vary
significantly, depending upon geographical location, degree of
urbanization and the nature of adjacent development. Land for
waste treatment, and in some cases for inert solids disposal, is
assumed to be contiguous with the production plant site and
reasonably convenient to a water way which can receive permitted
discharges of waste water. Where inert solids are retained at
the plant site, enough land is included in the base level model
plant investment cost to accept residual solids for a normal
operating period of ten years at the same production rate for
which the plant is sized.
For the purpose of this report, land for lagoons, treatment
facilities and on-site residual waste disposal is valued at
$30,000 per hectare ($12,000 per acre) .
Investment costs for supporting services - Engineering
design andinspection are typicalservices necessary to bring a
project from a concept to an operating system. Such services
broadly include laboratory and pilot plant work to establish
design parameters, site surveys to fix elevations and plant
layout, foundation and ground water investigations, and operating
instructions; in addition to design plans, specifications and
inspection during construction. These costs, which vary with job
conditions, are often estimated as percentages of construction
cost, with typical ranges as follows:
94
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Preliminary survey and construction surveying 1 to 2%
Soils and ground water investigation 1 to 2%
Labortory and pilot process work 2 to 4%
Engineering design and specifications 7 to 12'
Inspection during construction 2 to 3%
Operation and maintenance manual 1 to 2%
From these totals of 14 percent to 25 percent, a mid-value
of 20 percent of in-place construction (installed equipment and
construction) costs has been used in this study to represent the
engineering and design costs applied to model plant cost
estimates.
The contractor's fee and contingency, usually expressed as a
percentage of in-place construction costs, includes such general
items as temporary utilities, small tools, dewatering, field
office overhead and administrative expense. The contractor is
entitled to a reasonable profit on his activities and to the cost
of interest on capital tied up during construction. Although not
all of the above costs will be incurred on every job, an
additional 20 percent of the in-place construction costs has been
used to cover related costs broadly described as contractor's
fees, incidentals, overhead and contingencies.
Operation and Maintenance Costs
Annual operation and maintenace costs are described and
calculated as follows:
Labor and supervision costs - Plant operations are assumed
to be conducted 24-hours per day 350 days per year, with
attendance for only part of each working day. For batch waste
water treatments systems adjustment are made for the number of
working days in a year. Personnel costs are based on an hourly
rate of $20.00. This includes fringe benefits and an allocated
portion of costs for management, administration and supervision.
Personnel are assigned for specific activities as required
by the complexity of the system, usually 4 to 12 hours per day.
Energy costs - Energy (electricity) costs are based on the
cost of $306.00 per horsepower operating 24 hours per day and 350
days per year. For batch processes, appropriate adjustments are
made to suit the production schedule. The cost per horsepower
95
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year is computed as follows:
Cy= 1.1 (0.7457HP x Hr x Ckw)/(E x P) (1)
where
Cy = Cost per year
HP = Total horsepower rating of motor (1 hp = 0.7457 kw)
E = Efficiency factor (0.9)
P = Power factor (1.00)
Hr = Annual operating hours (350 x 24 = 8400)
Ckw = Cost per kilowatt-hour of electricity ($0.040)
Note: The 1.1 factor in equation (1) represents allowance
for incidental energy used such as lighting, etc.
It is assumed that no other forms of energy are used in the
waste treatment system.
Chemicals - Prices for the chemicals were obtained from
vendorsandthe Chemical Marketing Reporter. Unit costs of
common chemicals delivered to the plant site are based on
commercial grade of the strengths or active ingredient
percentages as follows:
Hydrated Lime (Calcium Hyroxide) Bulk $ 80/metric ton
Bag $ 85/metric ton
Quick Lime Bulk $ 70/metric ton
Ground Limestone $ 13.20/metric ton
Soda Ash (58% Bulk) $ 85/metric ton
Caustic Soda (58% NaOH) $200/metric ton
Sodium Sulfide (60-62%) $435/metric ton
Sulfuric Acid $ 75/metric ton
Hydrochloric Acid (32%) $ 70/metric ton
Aluminum Sulfate (56% Alumina) $250/metric ton
Flocculant (Polymer) $2.00/kg
96
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Sulfur Dioxide (Ton Containers) $335/metric ton
Chlorine (ton Containers) $220/metric ton
Sodium Bisulfide (72-74%) $385/metric ton
Ferrous Sulfate $ 70/metric ton
Diatomaceous Earth $ 0.30/kg
Activated Carbon $ 2.00/kg
Maintenance - The annual cost of maintenance is estimated as
10 percent of the investment cost, exluding land.
Taxes and insurance - An annual provision of three percent
of the total investment cost has been included for taxes and
insurance.
Residua1 waste disposal - Sludge disposal costs can vary
widely"! Chief cost determinants include the amount and type of
waste, and the choice of either on-site disposal or contract
hauling which depends on the size of the disposal operation and
transport distances. Off-site hauling and disposal costs are
taken as $13.00 per cubic meter ($10.00 per cubic yard) for bulk
hauling, with appropriate increases for small quantities in steel
containers. For on-site disposal from lagoons, a clamshell at
$600.00 and frontend loader at $300.00 per disposal day are used.
For very large sludge quantities, lower unit costs have been
assumed. The computed sludge quantities are spread on land
valued at $12,000 per acre.
Monitoring, analysis and reporting - The manpower
requirements covered by the annuallabor and supervision costs
include those activities associated with the operation and
maintenance of monitoring instruments, recorders, and automatic
samplers as well as the taking of periodic grab samples.
Additional costs for analytical laboratory services have been
estimated for each subcategory assuming that sampling takes place
three times a week at the point of discharge and that an
analytical cost of $20.00 per constituent is incurred.
Approximately 10 percent of the total analytical cost has been
added for quality control and water supply samples. Unless
otherwise stated, continuous discharge is assumed and the
analytical costs associated with compliance monitoring at the BPT
level are based on the determination of four constituents. At
the advanced (BAT) levels, the determination of six constituents
is assumed. A reporting cost of $1,500 per year is added for
clerical support. Monitoring costs for periodic batch treatments
are reduced in proportion to the number of days per year when
discharges occur.
97
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Amortization
Annual depreciation and capital costs are computed as
follows:
n n
CA = B[r(l+r) ]/[ (1+r) -1] (2)
where
CA = Annual cost
B = Initial amount invested excluding cost of land
r = Annual interest rate (assumed 10%)
n = Useful life in years
The multiplier for B in equation (2) is often referred to as the
capital recovery factor, and is 0.1627 for the assumed overall useful
life of 10 years. No residual or salvage value is assumed.
Items not Included in Cost Estimates
In some subcategories, a portion of the waste water is
returned to process from an intermediate treatment step. In
these cases, the costs of return piping and, pumping are
considered as water development and not as waste treatment.
Costs for subsequent treatment are based on the remaining flow
after diversion of the return-to-process flows.
Although specific plants may encounter extremes of climate,
flood hazard and availability of water, the costs of model plants
have been estimated for average conditions of temperature,
drainage and natural resources. It is assumed that any necessary
site drainage, roads, water development, security, environmental
studies and permit costs are already included in production
facilities costs. Therefore, the model costs are only for
facilities, supplies and services directly related to the
treatment and disposal of waterborne wastes, including land
needed for treatment and on-site sludge disposal. Air pollution
control equipment is not included, except for dust collectors
associated with treatment, chemical transfer and feeding. Raw
wastes from various sources are assumed to be delivered to the
treatment facility at sufficient head to fill the influent
equalization basin, and final effluent is discharged by gravity.
Costs of pumps, pipes lines etc., necessary to deliver raw waste
water to the treatment plant or to deliver the treated effluent
to the point of discharge are not included in the cost estimates.
Since the treatment models are designed to serve single
product manufacturing plants, no emergency holding basins or
98
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internal bypasses are provided. Any such necessary facilities
are more appropriately furnished as part of a combined waste
treatment system serving several product lines.
10.2 COST ESTIMATES FOR EACH SUBCATEGORY
Estimated costs for the waste water treatment plants for the
different annual productions and at various levels of treatment
are calculated in terms of total annual costs. The total annual
cost is the summation of the annual amortization of the
investment costs and the annual operation and maintenance costs.
The types of costs shown for each model plant are:
(a) Investment
(b) Annual operation and maintenance
(c) Annual amortization of investment costs (excluding land)
The total annual costs per metric ton of product have been
calculated.
For the purpose of the cost estimate, the first level of
treatment represents the base cost of the treatment system (BPT).
The other levels (second, third, etc.) represent the incremental
cost above the base cost. The actual additional costs a plant
would incur in implementing the described treatment processes
depend on current treatment practices, and to some extent on the
availability of land.
In some cases land for economical on-site sludge disposal
for a ten year period has been provided in the BPT model plant
costs. Since land cost is not amortized, its value appears in
the initial investment cost but not in the total annual costs.
Where land is a major factor in the BPT estimated costs, its
significance will be mentioned in the separate reviews of each
subcategory.
99
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SECTION 11
CHLOR-ALKALI INDUSTRY
11.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL - MERCURY CELL
11.1.1 Industry Profile and Analytical Results
Chlorine, hydrogen and caustic soda (NaOH) or caustic potash
(KOh) are produced together by electrolysis of brine. Chlorine
is used in pulp and paper industry, plastics, water treatment, as
an input in the manufacture of vinyl chloride, chlorinated
ethers, and other inorganic and organic chemicals. About
two-thirds of the production is for captive uses.
Chlorine - Mercury Cell Plants
The industrial
Table 11-1, and the
profile data for this industry is
existing regulations in Table 11-2.
given in
The priority pollutants found in siginficant concentrations
in the raw waste during sampling at Chlorine - Mercury Cell
Plants were as follows:
Pollutant
Maximum Concentration
ug/1
Screening
Observed
Verification (5 Plants)
Mercury
Copper
Chromium
Antimony
Arsenic
Cadmium
Lead
Nickel
Zinc
Thallium
Silver
150
350
7
<200
< 10
0
1
<100
230
<250
0
.7
.4
.6
27600
1480
235
950
400
787
1900
2450
34830
650
1455
A summary of daily and unit product raw waste loads for all
100
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TABLE 11-1
SUBCMEGORY PROFILE DATA .SUMMARY
SUBCATEGORY
CHLORINE MERCURY CFT,T,
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
3,545,000 kkg/year
2,750,000 kkg/year
32
15
1,280,600 kkg/year
1,090,000 kkg/year
36 percent
40 percent
19,100 kkg/year
198,000 kkg/year
77,900 kkg/year
70,400 kkg/year
75 percent
2 years
26 years
4 cubic meters/day
2,100 cubic meters/day
< 1 cubic meters/kkg
11 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Contnerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
101
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TABLE 11-2 - EXISTING REGULATIONS - EFFLUENT LIMITATICN GUIDELINES
SUBCATEGORY Chlorine and Sodium or Potassium Hydroxide
SUBPART F (40CFR 415.60, 3/12/74)
STANDARDS
Product Para-
Process meters
Mercury
Cell TSS
Process
*
BPCTCA BATEA" NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
(mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
0.64 0.32 No discharge ^ Q>32
or pwwp-
Hg
Diaphragm
Cell TSS
Process
Pb
0.00028 0.00014
n , .
°-64
n ,0
°'32
0.005 0.0025
No discharge
ofpwwp
of pwwp
0.00014 0.00007
0.64 0.32
0.00008 0.00004
*
Section 415.63 was remanded and is presently reserved C41 FR 51601,
November 23, 1976).
wax. = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants.
102
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plants sampled can be found in Table 11-3. Individual plant raw
waste loads per unit product (units kg/kkg) found in sampling can
be found in Table 11-4.
Based on the total annual production of this subcategory and
the average waste load generated per unit product, the estimated
total priority pollutant raw waste loads generated each year for
this subcategory are as follows:
Pollutant Waste Load (kg/year)
Mercury
Copper
Chromi urn
Antimony
Arsenic
Cadmium
Lead
Nickel
Zinc
Thallium
Silver
44000
910
250
1200
830
140
880
720
6300
830
610
11.1.2 Process Waste Sources and Waste Water Treatment Data
General Process Description
Currently almost all of the caustic soda and 95 percent of
all the chlorine produced in the United States is made by the
electrolysis of sodium or potassium chloride. Sodium chloride
is obtained by mining underground deposits or from the
evaporation of brine or sea water. Two types of cells are used
for the production of chlorine and caustic—mercury and diaphragm
cells. Mercury cells account for approximately 30 percent of the
production while the diaphragm cell accounts for 65 percent. The
Downs cell is another electrolytic process for producing chlorine
and sodium from fused salt. However, the amount of chlorine
produced by this process is relatively small. Since the
predominant method of making chlorine and by-product caustic is
by the use of mercury and diaphragm cells, this study of the
chlor-alkali subcategory is restricted to these two processes.
Because of the difference in cell design and the quality and
quantity of waste water produced, the chlorine subcategory has
been subclass!fied into two divisions; the mercury cell process
and the diaphragm cell process (See Section 4). Both the
processes are described later using sodium chloride as the
starting material. The same description holds true when
potassium chloride is the starting material, but with one
difference - the by-product produced in the latter case is
103
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TABLE 11-3. SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
SUBCATEGORY
Pollutant
Priority
Antimony, Sb
Arsenic, As
Cadmium, Cd
Chromium, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel, Ni
Silver, Ag
Thallium, Tl
Zinc, Zn
Conventional
TSS
CHLORINE-MERCURY CELL
Minimum
0.0059
0.00045
0.00032
0.0014
0.029
0.034
0.086
0.018
0.00036
0.0027
0.11
6.76
kg/day
Average
0.15
0.086
0.0091
0.028
0.11
0.068
2.84
0.046
0.058
0.071
0.42
307
Loadings
Maximum Minimum
0.29
0.27
0.025
0.094
0.020
0.13
6.71
0.072
0.22
0.14
1.10
1199
0.00001
0.000001
0.0000008
0.000004
0.0001
0.000089
0.0002
0.00003
0.00001
0.00002
0.0003
0.018
kg/kkg
Average
0.00045
0.0003
0.00005
0.00009
0.00033
0.00032
0.016
0.00026
0.00022
0.0003
0.0023
2.19
No. of Plants
Maximum Averaged
0.00074
0.01
0.0002
0.0004
0.0006
0.0007
0.063
0.0007
0.0008
0.001
0.01
10.8
3
5
5
6
6
5
6
4
4
4
6
-------
TABLE 11-4. PRIORITY POLLUTANT RAW WASTE LOADS (in kg/kkg of Product)
SUBCATEGORY
POLLUTANT
Mercury, Hg
Chronium, Cr
Thallium, Tl
Arsenic, As
Nickel, Ni
Cadmium, Cd
Copper, Cu
Lead, Pb
Zinc, Zn
Antimony, Sb
Silver, Ag
CHLORINE - MERCURY (TILL
PLANT *
#299 #167 #106
0.0002 0.013 0.006
0.000004 0.0004 0.00001
0.0001 0.0006
0.001 0.000002
0.0001 0.0002
0.0000008 0.00004
0.0005 0.0001 0.0001
0.0002 0.0005
0.0003 0.0006 0.001
0.0006
0.00001 0.0008
#747
0.0044
0.00004
0.000001
0.00003
0.00001
0.0002
0.0001
0.0005
0.00001
0.00002
#317
0.063
0.000048
0.00014
0.0003
0.0007
0.0002
0.0006
0.0007
0.010
0.00005
#299
.
0.008
0.00009
0.00029
0.0003
0.000004
0.00047
0.000089
0.0015
0.00074
*Does not include brine muds except for Plant #317.
105
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caustic potash (KOH) instead of caustic soda (NaOH) .
Mercury cell process - In the case of mercury cells, the 26
percent brine is reduced to only 22 percent NaCl for each pass
through the mercury cells. The spent brine is acidified with HC1
to ph3 and then blown with air or steam for dechlorination. The
residual traces of chlorine and chlorate ions are decomposed by
treatment with sodium bisulfite, and the brine is saturated by
the addition of salt for re-use.
As in the diaphragm cell process, the brine is purified by
the addition of caustic soda and sodium hydroxide to eliminate or
reduce the calcium, magnesium and iron impurities. The
precipitated waste is known as the brine mud and is similar to
the one produced from the diaphragm cell except that it contains
small amounts of ionic and metallic mercury from the re-cycled
brine. The precipitate is removed by filtration or
clarification. The final pH of the purified saturated brine
solution is adjusted to 3 to 4 by the addition of HCl. It is
then fed to the mercury cells.
The mercury cell, in general, consists of two sections; the
electrolyzer and the decomposer or denuder. The electrolyzer is
an elongated steel trough that is inclined slighty from the
horizontal and the mercury flows in a thin layer at the bottom.
This forms the cathode of the cell, and the brine flows
concurrently on top of the mercury. Parallel graphite or metal
anode plates are suspended from the cover of the cell. Electric
current flowing through the cell decomposes the brine, liberating
chlorine at the anode and sodium metal at the cathode. The
metallic sodium forms an amalgam with mercury.
2 NaCl(aq) + Hg = C12(aq) + 2 Na(Hg) (2)
The amalgam from the electrolyzer flows to the denuder. The
spent brine is recycled to the brine purification process. In
the denuder, the amalgam becomes an anode to a short-circuited
iron or graphite cathode. Deionized water is added to the
denuder which reacts with the amalgam to form hydrogen and
caustic. In modern mercury cells, the denuder or decomposer is a
horizontal or vertical laid graphite-packed bed. The water and
the amalgam flow countercurrently. The mercury is returned to
the electrolyzer. The caustic formed has a concentration of 50
percent NaOH. Some of the impurities present in the caustic are
removed or reduced by the addition of certain chemicals, and the
caustic is then filtered. It is, in most cases, sent to the
storage tank or is evaporated if 73 percent NaOH is the final
required concentration. The hydrogen gas is cooled by
refrigeration to remove water vapor and mercury. The processing
of chlorine gas is similar to the one practiced for diaphragm
106
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cell. Figure 11-1 is a flow diagram of chlorine/caustic
production using mercury cells.
Water Use and Waste Source Inventories
Water usage - The water uses common to both mercury and
diaphragm cells include noncontact cooling, cell washings, tail
gas scrubbing, equipment maintenance and area washdown.
Noncontact cooling water is used in cooling brine, caustic,
chlorine, rectifiers and compressors. Large amounts of water are
also introduced into the process through the salt solution.
One water application unique to the mercury cell process is
in the decomposition of mercury-sodium amalgam to form caustic in
the denuder. In mercury cell plants, the quantity of water usage
was found to range from 7.6 to 204 cubic meters per metric ton of
chlorine produced with noncontact cooling comprising
approximately 70 percent of the total.
Waste sources - Some of the waste sources produced during
the manufacture of chlorine and caustic by diaphragm and mercury
cells are similar with the notable exception of the presence of
mercury in the waste waters from mercury cells and asbestos
fibers in the waste waters from the diaphragm cell plants.
Following is a brief description of the common waste water
stream, followed by the individual streams specific to mercury
and diaphragm cells.
A. Common Wastes (Mercury Cell and Diaphragm Cell)
Br ine mud - This is the waste produced during the
purification of brine using soda ash and small amounts of caustic
soda before it is introduced into the cell for electrolysis. The
metals commonly removed during purification are magnesium,
calcium, iron and other trace metals such as titanium,
molybdenum, chromium, vanadium and tungsten. Calcium and iron
are removed as carbonates and magnesium and small amounts of
trace rnetals are removed as hydroxides. Brine mud is the major
portion of the waste solids produced from the process. The
solids content of the stream varies from 2 to 20 percent and
amount in volume to 0.04 to 1.5 cubic meters per ton of chlorine
produced. The waste is either sent to a pond or filtered. The
overflow from the pond, or the filtrate, is recycled to the
process as makeup water for the brine. In the mercury cell
process, only 16 percent of the NaCl solution is decomposed in
the cell and the unconverted brine is recycled to the
purification unit after dechlorination. This recycled brine is
contaminated with mercury arid, therefore, the resulting brine mud
contains small amounts of mercury.
107
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O
00
BRINE -**
I
CC
C
CHLORINE 1 f
PURIFICATION
SYSTEM
1
BRINE
MUDS
I
TO WASTE
1ONCONTACT
(CONTACT* )
K3LING WATER
JL
c
o
L
E
R
* .
:ONDENSATE
TO W
PURIFIED MFRPIIHY ^ -»_
"BRINE •*" MtKCUKY _ AMALGAM ^> DECOMPOSER *~ DEMINERALIZED
CELL WATER COOLER
fA A MUBfMinv 1 1 ~^~ *AND TO ATMOSPHERE
1 SO* SODIUM NUw«-vini««-i o^nuuuun, QJJ USE
SSUr?^ ,,Tm™ HYDROXIDE SOLUTION COOLING _^
COOLING WATER _L WRTPH ^^ ••- —
— ' T 1
^ "' COOLER CONDENSATE
tl ^^ TO WASTE
(SCRUBBING WASTE*) "~
1 COOLING
WATER — ». FILTER -5°* SODIUM PACKAGING ^- TOWER
^ HYDROXIDE . ... | TO SALES
BACKWASH SOLUTION TO
* ATMOSPHERE
BACKWASH RECYCLE _ BACKWASH 4 i
^ ^" FILTER CAUSTIC (LIME) | f
SOLIDS TQ INERTS
[~ LANDFILL
r~ ~i — —
L _,.__ rJ R
SULFURIC RECYCLED ^ 1 ' SOLIDS - -^.TO WASTE g
D R SOLUTION
y LIQUID .^TO SALES TO USE' SALES«
n i , , PRODUCT
' REFRIGERATION
EAK SULFURIC SYSTEM
ACID '"" i " " - -• 1 ' •
f NONCONTACT
RSTE COOLING
WATER
USED AT SOME PLANTS ONLY
Figure 11 -1. General process diagram for production of chlorine/caustic by mercury cells.
-------
Cell Room wastes - Tnis is another common waste stream
produced from both diaphragm and mercury cell but the volume and
characteristics are different in each case. The major components
of this stream include leaks, spills, and cell wash waters. The
amount varies from plant to plant and depends laryely on
housekeeping practices. The amount of cell room waste generated
per metric ton of chlorine, as a general rule, is higher for
diaphragm cell plants, and the waste water from the washing and
rebuilding of the cathode contains asbestos fibers, dissolved
chlorine, and brine solution. Every diaphragm cell is washed at
regular intervals with the washing period varying from plant to
plant. In mercury cell plants, the cell room wastes contain
mercury, dissolved hydrogen, chlorine, and some sodium chloride.
Cell room waste constitutes one of the major streams that
has to be treated for mercury. If graphite anodes are used in
either the mercury or diaphragm cells, the cell room wastes
contain lead and chlorinated organic compounds in addition to the
pollutants already mentioned. The majority of plants have
converted the cells from graphite anodes to metal anodes and few
plants are still operating with graphite anodes.
Chlorine Condensate - Condensation from the cell gas is
contaminated with chlorine. At some plants, the condensates are
recycled to the process after chlorine recovery. Both contact
and noncontact water is used for chlorine cooling and for removal
of water vapor and so the amount of waste water varies from plant
to plant. When graphite anodes are used, chlorinated
hydrocarbons, lead, and other impurities carried with the
chlorine condenses in the first-stage cooler. The chlorinated
organic compounds chat have been detected when graphite anodes
are used are: chloroform, methylene chloride, hexachlorobenzene,
hexachloroethane and hexachlorobutadiene (3) .
Spent Sulfur ic Ac id - Concentrated sulfuric acid is used to
remove the residual water from the C12 gas after the first stage
of cooling. In most cases, sulfuric acid is used until a
constant concentration of 50-70 percent is reached. The spent
acid might contain mercury, asbestos fibers, or chlorinated
hydrocarbons (depending on the type of cell) in addition to
chlorine. The volume of waste acid is typically of the order of
0.01 cubic meters per metric ton of chlorine.
Tail Gas Scrubber Liquid -The uncondensed chlorine gas from
the liquefaction stage, containing some air and other gases, is
scrubbed with sodium/calcium hydroxide to form sodium/calcium
hypochlorite. When the equipment is purged for maintenance, the
"sniff" gas, or tail gas, is absorbed in calcium or sodium
tiydroxide, producing the corresponding hypochlor i tes. The amount
of tail gas scrubber water varies from 0.04 to 0.58 cubic meters
per metric ton of chloride for botn diaphragm and mercury cell
plants, as shown in Table 11-5.
109
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TABLE 11-5. TAIL GAS SCRUBBER FLOW DATA FOR CHLORINE/CAUSTIC SUBCATEGORY
«-
#858
#967
#967
#317
#299
#674
Type of Cell Used
Diaphragm
Diaphragm
Diaphragm
Mercury
Mercury
Mercury
Tail Gas Scrubber Flow
m /kkg of Cl-
0.16
0.28
0.104
0.045
0.108
0.578
110
-------
Caustic Filter Washdown - The 50 percent caustic produced
from both mercury and diapnragm cells is treated with chemicals
and filtered to remove salt and other impurities. The filters
are back-washed periodically as needed, the waste water volume is
variable, and usually contains small amounts of mercury or
asbestos fibers in addition to the salt.
B. Process Specific Wastes
Condenser Drainage - In mercury cells, the hydrogen produced
is cooledin surface condensers to remove mercury and water that
is carried over with the gas. The waste water is either sent to
the waste water treatment facility or sent to the mercury
recovery facility. After mercury recovery, the water may be
discharged to the treatment facility or returned to the denuder
after deionization. Information on the volume of this waste
stream is not available.
Control and Treatment Practices
Mercury Cell Plants Visited and Sampled
Plant #299 was visited in the screening and verification
phase of the program. The mercury-contaminated waste streams
include outlet end-box wash water, spills and cleanup water,
brine mud saturator sludge, and pump seals waste water. The
combined waste water is sent to settling ponds where the
suspended solids are separated. The effluent from the ponds is
treated with sodium sulfide and the phi adjusted. The reactor
solution is filtered in a filter press and the filtrate passed
through activated carbon before discharge. Figure 11-2 gives the
general process diagram and shows the streams sampled. Table
11-6 gives the unit flow data and the important pollutant
emissions.
Three more plants (#747, #167, and #317) producing
chlorine/caustic by mercury ceils were visited and waste water
sampled in the verification program.
At Plant #747, the brine dechlorination system has been
converted from barometric condensers to a steam ejector system.
The conversion resulted in increased chlorine recovery and
reduced contact waste water. oy providing settling and secondary
filter facilities, tne brine filter backwash has been eliminated.
The tail gas scrubber liquid is offered for sale and if not
marketed, is decomposed. The mercury bearing waste waters are
collected and treated with Na2S. The reacted solution is
riltered and the filtered solids are retorted for mercury
recovery. The filtrate is mixed with the other process waste
waters and the pd adjusted before discharge. The flow diagram of
111
-------
WELL WATER
<*4) $f #4 <»!> ^
BRINE MUD
SALT ^ BRINE ^ RRTME BRINE ^ CCLL
""" SATURATION PURIFICATION *"~
t t
Naai Na2C03
NfiflH TY> ^^
STORAGE
^ 13
/
v^/^
*1
HOUSE
H20
H2
i^\ te. -nrrrnrn 2 te. DEMINERALJZER
^*^ IMAKE-UP HZO
I
H2° °£^ H20 TO PROCESS
BACKmSH FROM PROCESS
1 > 1 SLOWDOWN 1
[•E
^—
REGENERATION
I
" y«2, MKtA'i'bU W/to'lli
Hfj PDND (jf) ^*
TREAIMEOT ^^^ TO A1MDSPIIERE
* ?
1 1 (II 3)
TAIL GAS (ffi\ ^ WASTE TO
SCRUBBER N^S^ RJVKK
»5
t
C12 _ C12COMP.
AND *"
LIQUEFACTION STORAGE
H2 PURIFICATION H
1
UTILITy
BLOWDOWN
1
SURGE TANK H_O TO RIVER • !»•
e
Waste streams sampled.
Numbers in ( ) were sampled in
screening, others during verification.
Figure 11-2. General process flow diagram at Plant 0299 showing the sampling points.
Chlorine/Caustic (Mercury Cell) Manufacture
-------
TABLE 11-6. FLOW AND POLLUTANT CONCENTPATION DATA OF THE SAMPLED WASTE STREAMS
FOR PLANT#299 PRODUCING CHLORINE BY MERCURY CELLS
________________________^_^^____ . _ . ___
Stream
No.
1
2
3
4
Stream
Description
Cell Waste
Mercury Treatment
Effluent
Tail Gas Scrubber
Brine Mud
Unit Flow
m3/kkg
of C12
1.416
1.475
0.128
NA
TSS
kg/kkg
of C12
0.016
0.007
NA
NA
Mercury
kg/kkg
of C12
0.0002
0.00004
NA
NA
Lead
kg/kkg
of ci
0.000001
0.000006
<0. 000006
NA
Verification Phase
3
4
5
Inlet to Mercury
Treatment
Mercury Treatment
Effluent
Cell Waste
Brine Mud
Tail Gas Scrubber
1.475
1.475
0.276
0.026
0.173
*
1.416
NA 12874
0.128 0.022
0.00831 <0.00008
0.0003 <0.00007
0.0145 0.0002
0.545* 0.663*
0.00002 0.00001
NA = Not Available
mg/1
113
-------
the manufacturing process, including the waste water treatment
facility, is given in figure 11-3. Table 11-7 gives the flow
data for the sampled streams.
At Plant #167, the waste water streams, consisting of filter
backwash, cell rooia wash, rain water runoff, and leaks and
spills, are combined and treated for mercury removal. The water
is sent to a holding lagoon and tne overflow is reduced by
reaction with ferrous chloride, which precipitates mercury. The
reacted solution is sent to a clarifier and the underflow from
the clarifier is disposed of in a landfill. The overflow is
filtered and the filtrate is passed through activated carbon and
an ion exchange column prior, to discharge to a lagoon. Tne
effluent from the lagoon is pti adjusted and discharged. Figure
11-4 shows the simplified process flow diagram for Plant #167,
including the sampling locations. Table 11-7 gives the flow data
and pollutant emissions for the sampled streams.
At Plant #317, the brine purification mud is mixed with
spent sulfuric acid and sodium hypocnlorite solution. The
treatment removes mercury from the mud and transfers it to the
solution. The solution is filtered and the solids landfilled.
The filtrate is mixed with other mercury-contaminated waste
waters, which includes tne brine purge, cell room liquid wastes
and plant area wash water. This is then reacted with sodium
hydrosulfide to precipitate tne mercury as mercury sulfide and
then filtered. The solids are sent to a mercury recovery unit
and the filtrate is sent to a holding tank. The effluent from
the holding tank is mixed with de-ionizer waste and noncontact
cooling water before discharge. The process flow diagram showing
the waste streams sampled art; given in Figure 11-5. Table 11-7
is a summary of flow data and pollutant emissions for the sampled
streams.
Treatment Practices-Mercury Cell - Treatment practices at
other mercury cell chlorine producing plants not visited and
sampled are discussed in tiie next few pages.
At Plant #261, the cell waste water is filtered and the
rilter cake and other asbestos solids are disposed of at an
off-site landfill after being placed in plastic bags which, in
turn, are packed in drums. brine pur ificiation muds at this
facility are utilized for their alkalinity on-site and then they
are settled prior to discharge of the supernatant. Spent
sulfuric acid is used for neutralization of tne waste waters.
Uechlorination of the drying acid by reaction with sodium
bisulfite is planned in the near future.
At Plant #589, the waste water going to tne mercury
treatment system consists of cell room washdown, brine filter
backwash, leaks, spills, cleanup water, and hydrogen cooling
condensate. The waste waters are reacted witn hydrochloric acid
114
-------
ALKALI
RECIRC.
COOLER
fttfa 16
ci2
E»>«S3
DRYING
ci2
COMPRESSION
AND
LIQUEFACTION
SClflJbWER ^N^ ^
§7
1^- CHLORINE
PRODUCT
65% H2SO. WASTE
TO PONDS
•HYPoaiLORjTE
SOLUTION
NaOH
Waste streams sanpled.
DISCHARGE
SOLIDS TO
LANDFILL
MERCURY TO PROCESS
Figure 11-3. General process flow diagram at Plant 1747 showing the sampling points.
Chlorine/Caustic (Mercury Cell) Manufacture
-------
TABLE 11-7. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE STREAMS
FOR PLANTS #747, #167 AND #317 PRODUCING CHLORINE BY MERCURY CELLS
Plant
#747
#167
#317
Sampled
Stream
No.
1
2
3
4
5
6
7
5
6
7
8
9
1
2
3
4
5
6
7
8
Stream
Description
Cell Waste
Treated Waste
Input C12
Drying Tower
Output C12
Drying Tower
Dechloro
System
C12 Condensate
Tail Gas-Hypo
All Chlorine
Wastes
Cell Wash
Brine Process
Water
Treated
Chlorine Waste
Brine Mud
Cell Waste
Brine Mud
Filtrate
Tank Car Wash
Collection
Tank (H2+3)
Treated
Effluent
Deionizer
Effluent
Flow
nrVkkg
of C12
0.23
0.23
0.15
0.24
0.43
0.0067
0.022
3.35
0.0093
1.78
5.58
0.67
0.29
0.54
0.11
0.41
0.41
0.29
N-C Cooling 135
Water
Final Effluent
136
Pb
Load
kg/kkg
of C12
7.3 x 10~5
1.7 x 10~5
4.1 x 10~4
1.4 x 10~5
4.3 x 10~6
8.7 x 10~7
3.1 x 10"5
2.4 x 10~4
2.6 x 10~6
1.8 x 10"5
6.5 x 10~4
6.96x 10~3
3.98x 10~3
6.3 x 10~5
1.1 x 10~5
2.8 x 10~2
6.8 x 10~5
3.8 x 10~6
1.4 x 10~3
3.2 x 10~3
SS
Load
kg/kkg
of C12
0.16
0.014
NA
NA
0.0037
2.7 x 10~5
NA
1.89
5.7 x 10~4
7.1 x 10~3
1.3 x 10~2
3.99
0.013
0.28
1.98x 10~3
8.67
4.4 x 10~2
5.2 x 10~3
2.16
2.45
Hg
Load
kg/kkg
of C12
4.3 x 10"3
2.3 x 10~5
3.5 x 10~6
7.2 x 10~7
1.5 x 10~5
1.8 x 10~6
8.0 x 10~7
1.3 x 10~2
6.7 x 10~6
9.0 x 10"6
1.8 x 10~3
8.7 x 10~5
1.4 x 10~5
1.9 x 10~2
3.6 x 10~6
5.6 x 10~4
4.3 x 10~5
2.9 x 10~7
1.4 x 10~4
3.6 x 10~4
NA = Not Analyzed
116
-------
SALT
I—
NONCONTACT ll-O
TO WASTE I1,O NaOlI
Waste streams sampled
»7
TO pH ADJUST- •*
MENT AM) FINAL
DISCHARGE
LAGOON
<«&}
«8
ION
EXCHANGE
ACTIVATED
CARBON
•^ • —
SAND FILTER
«*—
CLARIFIER
^
M i
1 Ut
UNDERFLOW TO
LANDFILL
Figure 11-4. General process flow diagram at Plant #167 slrawing the sampling points.
Chlorine/Caustic (Mercury Cell) Manufacture
-------
SALT
I—
CO
e
OFF GAS
t
Haste streams sampled.
DE-IONIZED NOMXNTACT
WATER WASTE COOLING
tin
TANK CAR WASH
TO WASTE TREATMENT
TO DISCHARGE
«8
Figure 1 1-5. General process flow diagram at Plant H317 showing the sampling points.
Chlorine/Caustic (Mercury Cell) Manufacture
-------
and sodium bisulfiue and then sent to a settling oasin where
mercury sulfide precipitates. The overflow is passed through a
series of effluent filters before discharge.
At Plant #343, the cell room wash water, brine purification
sludge, and cnlorine cooling condensate are combined and sent to
a pond. The suspended solids settle in the pond and are dredged
out once a year. The dredged sludge is "Chein Fixed" and disposed
of iii an appropriate landfill. The overflow from the pond is
reacted with Na2S and the reacted solution is sent to a
clarifier. The clarifier underflow, consisting mainly of mercury
sulfide, is returned to the pond. The clarifier overflow is
d ischarged.
All contact waste water at Plant #907 is treated for mercury
removal in a patented process involving reduction of mercury to
the metallic state by use of sodium borohydrate. All contaminated
wooden rlooring in the cell room has been removed and replaced
with fiberglass gratings to reduce the amount of mercury in the
effluent treatment system and for better waste control. Molecular
sieves have been installed on cell end boxes to reduce the
mercury content in the air vented from tne cells. The treatment
not only cleans the air but is also believed to reduce mercury in
the plant area runoff.
In the treatment system, the mercury-contaminated waste
water is reacted with sodium borohydride to reduce dissolved
mercury to the metallic form. The reacted solution is filtered
prior to delivery to one of tne banks of three columns packed
with antnracite coal. After passing through tiiree absorption
columns in series, tne treated waste water is delivered to large
holding tanks, from whicli it may be discharged or returned to
treatment, depending on its mercury content. Filter cake,
resulting from the filtration of the waste prior to the coal
absorption step, is retorted for mercury recovery.
Waste solids at this facility, including mercury treatment
sludges and brine muds, are deposited in an on-site disposal
area. Chlorine discharges are essentially eliminated by three
significant practices: the chlorine condensate is collected and
returned to the brine system, tail gas scrubbing effluents are
used in the manufacture of another product, and spent sulfuric
acid from chlorine drying is dechlorinated in an air stripper and
snipped off-site for the manufacture of another product. Gases
from tne air stripper are returned to the chlorine purification
header.
At Plant #324, tne barometric condenser on the brine
dechlorinator was replaced with an indirect cooler, resulting in
a reduction of chlorinated waste water. The tail gas scrubber
effluent is used for the manufacture of anotrier product, and the
brine muds are sent to a pond. Small amounts of mercury, when
119
-------
detected in the brine mud, are ieacned with water and treated
with other mercury-contaminated waste waters which include the
cell room wash water, caustic filter DacKwasn, and brine leaks.
The combined waste water is sent to a sump and then mixed with
nyarogen processing waste water before introduction into a second
sump. The waste water from the second sump is reacted with
sulfuric acid, sodium boronydride, and sodium sulfide. The
reacted solution is filtered. The filtrate is pH adjusted and the
caKe slurry is sent to a brine recovery sump. The underflow from
ttie sump is sent to a pond and the overflow recycled to the
process.
The mercury-bearing waste waters are combined and sent to
trie treatment facility. The streams sent to the treatment
facility include the caustic filter backwash, cell outlet end-box
wasn water, spills and cleanup, clarifier sludge, saturation
sludge, and pump seals. The waste waters are sent to the
settling pond where the suspended solids are removed. The
overflow from the pond is reacted with NariS, ptt adjusted, and
then filtered. The filtrate passes through an activated carbon
column before discharge. The depleted tail gas scrubber liquor
is discharged at this plant witnout treatment.
At Plant #385, the brine mud sludge is sent to a retention
pond where it accumulates. All process contact waste water is
collected in an unlined pond wtiere it is treated and the treated
effluent is used as the scrubber liquid for tail gases. The
spent scrubber solution is sent to an adjacent paper plant for
use.
At Plant #416, the ceil room wastes are used for bleach
manufacture. The waste wacer streams from the chlorine/caustic
plant are sent to an adjacent paper company.
At Plant #784, the waste water, consisting of KC1 brine
filter backwash and area wasndown and spills, is sent to a basin.
The basin equalizes the now and the overflow is treated with
sulfuric acid prior to reaction witn NahS and clarification. The
clarifier overflow passes through an activated carbon filter and
co a final tan*, where it is given pH adjustment before discharge.
The wastes are segregated at Plant #674. A clarification
pond is used for waste streams containing suspended solids. The
streams going to tiie pond include brine purification muds and
spent chlorinated lime. The mercury-contaminated waste waters,
which include tiie brine saturation waste, brine filter backwash,
cell room sumps, and tank car wasiies, are combined and treated
for mercury separately. The combined mercury-laden waste water
is sent to a collection pond and the overflow from the pond is pH
adjusted before tiie addition of Na2S. The reacted solution is
sent to a another pond and the pond overflow is passed through a
carbon absorption column before final discharge. A part of the
120
-------
treated effluent is re-injected into the brine well.
At Plant 4012, the brine treatment area is paved to trap all
spills, leaks, and rain runoff from that a'rea. The recovered
waste is recycled to the weak brine reservoir. The contaminated
waste waters from the plant are re-injected into the brine wells
to keep the hydraulic balance and maintain pressure in the salt
deposits.
At Plant #106, the tail gases are scrubbed with sodium
hydroxide and the sodium hypochlorite solution formed is sold to
an adjacent pulp and paper plant. When not marketed, the
hypochlorite solution is thermally decomposed by discontinuing
the flow of cooling water to the tail gas absorption system.
Without cooling, the unit attains the temperature required for
decomposition. The brine mud is sent to a hypalon-lined lagoon
for sedimentation and tiie overflow is returned to process.
molecular sieves are used to remove mercury from the hydrogen
gas.
Mercury-bearing wastes are segregated from other waste
waters and combined for treatment. Mercury-bearing leaks,
spills, and precipitation are contained and collected by curbing
around the cell room and are pumped to treatment from a common
sump. In the treatment system, the ph is initially adjusted
using waste sulfuric acid and 20 percent caustic solution as
required. Sodium sulfide and filter aid are added and the waste
agitated in fiberglass reaction tanks. The effluent from the
tanks is filtered and the filter caKe is retorted for mercury
recovery. The residual waste, after mercury recovery, is placed
in a lined solid waste disposal area. The filtrate is sent to
the first of the two lined lagoons. Primary ph adjustment is
made using waste sulfuric acid and 20 percent caustic before
entry into tiie first lagoon; final pa adjustment is made between
the first and tne second lagoons.
Ta il gas emission control - when chlorine gas produced from
the cell is compressed and cooled, chlorine separates as liquid
chlorine and noncondensable gases, known as tail or sniff gas
containing chlorine vapor, are produced at the discharge end of
the condenser. The tail gas is scrubbed to remove the chlorine
and the amount escaping in the atmosphere with the tail gas
depends on the operating conditions and the removal/recovery
method employed. Emissions vary, depending on the plant
capacity, presence of inerts in the gas and also on the injection
of air into the chlorine condenser to prevent an explosive
mixture in the vent gas. The amount of chlorine present in the
tail gas is significant and the chlorine has to be removed and
treated or recovered before venting into the atrnospnere. The
common industrial practice is to scrub with caustic soda or 1 irae
solution thus producing the corresponding hypochlorite. The
nypochlorite is either soid, used on-site, sent to the waste
121
-------
water treatment plant, or discharged without treatment.
Treatment of tiiis waste is a relatively recent practice.
Decomposition is a common method of treatment using catalytic,
thermal, and chemical methods.
Catalytic decomposition involves the addition of small
quantities of cooalt, nickel, and iron chloride to the waste
streams, followed by retention in reaction tanks for periods up
to several days. Of the two plants employing this technology,
one reports zero discharge of chlorine, and the other reports
average and maximum chlorine discharge rates of 0.015 and 0.14 kg
per metric ton of chlorine produced.
Thermal decomposition takes place when the temperature of
the solution containing hypochlorite reaches 175 degrees F. When
lime is reacted with chlorine, it results in an exothermic
reaction producing heat and calcium hypochlorite. If the
hypochlorite solution is not cooled, it results in thermal
decomposition. One chlorine/caustic plant is using this treatment
method arid another is planning to use it. The plant using
thermal decomposition reports complete conversion of hypochlorite
to chloride.
Chemical decomposition takes place by reacting the
hypochlorite solution with a chemical reactant which is usually
sodium sulfite or hydrogen peroxide. Chemical decomposition is
expensive but complete and rapid.
When chlorine is present in a dissolved form in water, a
stripping technique is applied to recover the chlorine. Chlorine
condensate streams and spent chlorine-drying acid are most
commonly treated by steam or vacuum stripping, with the chlorine
frequently returned to the process for purification and recovery
as a product. The tail gas is not generally scrubbed with water
because water does not effectively remove chlorine and the
chlorine concentration in the exhaust will reach 0.1 to 4.5
percent by volume after scrubbing with water. One effective
method of chlorine recovery from the tail gas is by the passage
of the gas through an absorbing material such as carbon
tetrachloride and subsequent recovery of the chlorine. The
process is proprietary and little information is available on its
design or operation.
Evaluation of Industry Production and Waste Flow Data
Chlorine/caustic manufacture with either mercury or
diaphragm cells yields a number of distinct effluent streams
wnich differ appreciably in their volume and chemical
composition. Segregation of tnese waste streams is a primary
control practice in the industry, and allows effective treatment
at acceptable cost levels.
122
-------
In the plants producing chlorine via mercury cells, the
contact waste waters are segregated into three different streams
ror effective treatment. One is the brine mud, contains
appreciable amounts of suspended solids. The solids are the metal
precipitates and other contaminants present in brine and removed
during purification of brine. It may contain small amounts of
mercury. The second segregated stream is the
chlorine-contaminatea waste water. It is similar to the one
discussed under diapnragra cells. The last segregated stream is
the mercury contaminated waste wacer. It consists of the brine
and caustic filter oackwasn, cell room wastes, hydrogen cooling
condensate, etc. Table 11-8 gives the unit flows of the
segregated streams for plants whose data is available.
Process Modifications and Technology Transfer Options
Anode Mater ial - In the majority of cases, in botli mercury
and diapnragm cells, tne anodes have been changed from graphite
to metal. The use of metal anodes increases the cell current
efficiency and eliminates or reduces considerably the chlorinated
organic compounds and lead in tiie waste waters. The metal anodes
consist of an expanded titanium metal substrate coated with
precious metal and rare earth oxides.
Liquefaction of Calorine - Utilization of refrigeration and
high pressure for chlorine recovery will reduce the chlorine
content in the tail gases. This technology is presently being
practiced at a number of production facilities.
Best management Practices
Area runoff - Storm runoff from the plant area for chlorine
plants using mercury cells can be collected and sent to the waste
water treatment plant.
Mercury emissions - Hydrogen gas produced from the cell can
be passed through molecular sieves to remove the mercury escaping
with the gas. This will reduce the mercury emissions and reduce
atmospheric fallout in the neighborhood of the plant. This in
turn will reduce mercury concentrations in storm runoff. Two
plants are practicing this control treatment.
Leaks and spills - The brine treatment area and the cell
room areas, especially in the mercury cell plants, should be
paved with fiberglass gratings, and provision should be made to
collect the leaks and spills from the operation.
Mercury contaminated solids - The precipitated mercury waste
should be stored in a lined pond or disposed of in a secured
landfill. in tne mercury ceil plant, tiie brine mud should be
123
-------
TABLE 11-.8. WASTE FLOW DATA FOR CHLORINE/CAUSTIC SUBCATEGORY USING
MERCURY CELLS
Stream Description Plant Unit Flow m /kkg of chlorine
Brine mud # 589 0.651
# 674 0.874
Tail gas scrubber #317 0.046
(hypochlorite solution)
# 299 0.109
# 385 3.39
# 674 0.58
# 167 2.25
Mercury contaminated # 343 1.57
waste waters
# 907 0.357
# 317 0.529
124
-------
placed in lined pond or disposed of in a secure landfill after
filtration. The brine mud contains small amounts of mercury
which can leach into the ground water if proper safety
precautions are not taken.
Tail gas emissions - The tail gases, after the liquefaction
or recovery of chlorine, should be scrubbed with lime or caustic
soda to remove residual chlorine from the vented gases.
Scrubbing with water is not efficient as shown by the following
data:
Emissions Factor,
Type of Chlorine Concentration kg chlorine/kkg
Control In hxhausc, vol. 'a Chlorine Liquefied
None20 to 50 10 to 80
water Absorber 0.1 to 4.5 0.125 to 5.45
Caustic or Lime 0.0001 0.000125
Scrubber
Transportation, handling and abnormal operations
Prpvisions should be" made to remove chlorine from air emissions
resulting from abnormal operating conditions such as start up and
shut down, or from vents on returned tank cars, and ton
containers, cylinders, storage tanKs, and process transfer tanks
during handling and loading of liquid chlorine.
Model Plant and BPT Treatment System Specifications
Mercury Cell Plants - The recommended BPT treatment for the
waste waters from chlorine plants using mercury cells consists
of:
A. filtration of the process waste flow to remove
precipitated heavy metals.
b. Lagoon settling of brine mud and long term storage
at site.
C. Partial recycle of the brine waste stream to process.
D. Precipitation of mercury as mercury sulfide from
the mercury-contaminated waste water streams for
recovery or disposal.
Approximately 50 percent of the production data for all the
chlorine/caustic plants using mercury cells is available on file.
Production ranges from 19,000 to 1^8,000 kkg of chlorine year.
Three model plants with productions of 25,300, 126,000 and
253,000 kxg/yr were selected to represent the subcategory
production range. The flow per unit of production is assumed to
125
-------
be the same for each size of model plant.
A. ^vaste water flow: tor model plants, the contact waste
waters from the mercury cell process are segregated into two
streams. The brine mud produced during the purification of brine
is segregated to remove the suspended solids present in it. The
clear liquid, after settling, is recycled to the process. A unit
flow of 0.42 m3/kkg of cnlorine was taken for the model plant,
with a suspended solids content of 10 percent. Trie other
segregated waste water is process waste effluent contaminated
with raercury. It includes the orine and caustic filter backwash,
cell room waste water, hydrogen cooling condensate and decomposed
scrubber waste water. A unit tlow of 1.2 ia3/kkg of cnlorine was
taken for the second segregated stream.
B. Chemicals used: Sodium bisulfide was used in an amount
equivalent to 0.025 kg/kkg chlorine to precipitate mercury and
other metals.
C. Solid waste produced: The brine rnud constitutes the
major source of solid waste produced from the process/treatment
facility. Mercury sulfide and small amounts of other metal
sulfide constitute the residual solid waste. The total quantity
is 41.7 kg/kkg of chlorine produced.
General assumptions on chlor ine bear ing wastes - In the
selection of model plants, the following assumptions have been
made for the chlorine contaminated waste streams. The chlorine
condensate waste stream has not been included in the waste
streams going to the treatment facility. In the majority of the
chlorine/caustic plants, this streaw is stripped of chlorine by
steam or vacuum and the chlorine is recycled to the purification
operation. The waste water is then returned to the process and
introduced to the brine purification unit or sent to the
treatment unit. The quantity of waste water generated by this
operation is small. In soiae cases the chlorine gas from the cells
is contact cooled with water and the scrubbed liquid, after steam
stripping, is reused. The stripping operation in the recovery of
chlorine is part of the process and, therefore, its cost is not
included in the treatment cost. In tiie case of plants using
grapnite anodes, the chlorine condensate contains chlorinated
organic compounds and some lead in tiie waste waters. This waste
is sealed in drums and disposed of in a secure landfill. At
present, very few plants are using graphite anodes and land
disposal is a good disposal method.
The spent tail gas scrubber solution, which is mainly
calcium/sodiurn hypocnlorite, is assumed to be decomposed before
it is discharged. Tnermal decomposition can be practical at no
additional cost, while anotiier efficient method of decouiposition
is catalytic decomposition. (its costs are given separately under
Estimaced Control and Treatment Costs for tiiis industry and have
126
-------
not been included in the model plant costs.) The reason for
excluding this cost is that in many plants the hypochlorite waste
stream is either sold or used cm-site. If neither of these two
alternatives is available, then it is decomposed and discharged.
The hypochlorite stream is thus not continuously treated at
all plants and the cnoice between nandling it as a by-product or
a waste is largely dependent on the local marKet demand.
11.2 TECHNOLOGY BASED POLLUTION ABATEMENT
11.2.1 Advanced Level Treatment Applications
Priority Pollutants to be Controlled
Existing chlorine plants using mercury cells are already
controlling mercury in their waste waters in response to current
regulations wiiich call for a discharge of less than 0.00014
Kg/kkg of product as a 30-day average. Potential candidates for
control are the common heavy metals: chromium, nickel, zinc,
copper, and antimony, as well as thallium and arsenic, most of
which respond to the sulfide process for mercury precipitation.
Inventory of Priority Pollutants Present in Process Operations
In addition to mercury, lead and asbestos, waste waters from
the chlorine industry may contain chromium, copper, zinc,
thallium, nickel, arsenic, and antimony, some of which
undoubtedly represent corrosion products from reaction between
chlorine and the plant materials of construction. With the
pnasing out of graphite anodes, cnlorinated organics are not
common constituents of mercury cell plant waste waters, although
some may originate by the contact of chlorine with rubber linings
and F.R.P. components. Traces of certain priority organics were
found but none in significant concentrations.
Removal Mechanisms Available
wost of the above listed pollutants, will be essentially
removed by sulfide precipitation and filtration. The exceptions
are cnromium and asoestos. All of the heavy metals can be
controlled by alkaline precipitation and filtration, witii varying
degrees of specific metal removal at a given ph.
127
-------
Selection of Appropriate Technology
mercury Cell - BPT (Level 1) - Sulfide precipitation
followed by pressure fiftration is chosen as the best available
technology for separating mercury and other heavy metals (except
chromium) . Hexavalent cnromium will be reduced to its less toxic
trivalent form, but may remain in solution, depending on final
pH.
Mercury Cell - Level 2 - The filtered Level 1 effluent is
passed tnrough a granular activated carbon bed, wnere residual
metal sulfides and any metallic mercury will be adsorbed. This
treatment was cnosen over ion exchange because at low pollutant
levels tne carbon bed need not be regenerated but can be replaced
with new carbon at approximately one-year intervals. Although
ion exchange resins could be similarly replaced, they would not
adsorb reduced metallic mercury. There is insufficient
performance data to recommend the xanthate process at this time
as an alternative to sulfide precipitation.
Flow Diagrams
Treatment process components for the multiple waste streams
of the mercury cell process are shown in Figure 11-6 (Level 1)
and Figure 11-7 (Level 2).
Description of Each Treatment Level
Equipment functions - In both processes the metal-
contaminated wastes are equalized in a surge tank. In the Level
1 mercury process, mercury sulfide precipitate is removed in a
conventional plate and frame filter press. At Level 2 the
mercury process metal-bearing wastes are passed through a
conventional granular activated carbon filter for adsorption of
any residual mercury.
Chemicals arid handling - In tiie mercury cell process, sodium
bisulfide is used for mercury sulfide precipitation at pH 5 to 7.
Care is needed to prevent escape of toxic and obnoxious H2S fumes
at ph levels below 7. At Level 2 no additional chemicals are
used since the activated carbon bed is not regenerated but is
periodically removed and replaced. The handling of granular
carbon may cause temporary dust probleias but it causes no special
hazards.
Separation and removal or sol ids - In all processes
conventional settling and filtration are used to separate solids.
because hazardous asoestos, mercury, and toxic metals remain
in the solids, all sludge (except brine mud) snould be disposed
128
-------
LAGOON
BRJNE
MUD STREAM"
LAGOON
RECYCLE
-*.TO PROCESS
tsj
MERCURY
CONTAMINATED-
WASTE STREAM
SULFURIC ACID
FILTER
AID
*
ADJUSTMENT
SODIUM BISULFIDE
D
FILTER
HOLDING TANK MIXING
MIXING
SOLIDS '
TO MERCURY I
RECOVERY i
OR LANDFILL I
EMERGENCY RETURN LINE
-». EFFLUENT
Includes pH monitoring, flow monitoring and sampler
Figure 11- 6 • Vfeste watar treatment level 1 for chlorine - mercury cell subcategory.
-------
BRINE
MUD STREAM
CO
o
MERCURY
CONTAMINATED
WASTE WATER
LAGOON
LAGOON
RECYCLE
_^. TO PROCESS
r
CZr
BACKWASH
FILTER AID
SULFURIC ACID
I I SODIUM
L--' BISULFIDE
HOLDING TANK
MIXING
MIXING
FILTER
pH ADJUSTMENT
SOLIDS
I TO MERCURY '
I RECOVERY QR |
I E_MERGE::CY RETURN Li:'E LANDFILL |
|
ACTIVATED
CAREOI!
1
-Q
-*~ EFFLUENT
Includes pH monitoring, flow monitoring and sampler
Figure 11-7 . Haste hater treatment Level 2 for chlorine - mercury cell subcategory
-------
of in a safe cnemical waste area.
Monitoring requirements - Monitoring of heavy metals
including mercury, is done by atomic absorption methods, usually
at a qualified commercial laboratory. Simple field tests for
heavy metals as a group are available for routine process
control .
11.2.2 Estimated Performance of BPT Systems
waste water control and treatment practices at chlor-alkali
plants involve waste segregation since specific pollutants arise
in separate waste streams. Examples of these are pollutants
common to both mercury cell and diaphragm cell plants, mainly
suspended solids and chlorine.
Chlorine, as hypochlor i te , primarily arises from alkaline
scrubbing of noncondensibles following product recovery. The
resultant hypochlorite stream is often used in another process or
sold. A few plants now remove the chlorine by thermal or
catalytic decomposition or by stripping before discharge, but
many plants discharge the waste without treatment. Table 11-9
presents residual chlorine effluent loadings at plants which use,
sell, or treat chlorine-bearing waste waters.
Mercury Cell Plants - Because it has been limited in
discharge permits for some time, mercury removal technology is
employed at almost all mercury
mercury-contaminated streams are
precipitated as the sulfide
filtration. Mercury recovery is
shown iii Table 11-10, this technology is highly
reducing mercury discharges.
cell plants. Most commonly,
segregated and the mercury is
and removed by settling or
practiced at some plants. As
effective in
BPT technology for waste water treatment and control at
mercury cell chlorine plants has been specified and includes
containment of mercury-bearing waste waters followed by sulfide
precipitation and filtration before discharge.
The pollutants previously regulated at mercury cell chlorine
plants are suspended solids and mercury. Priority pollutants
other than mercury that were found at significant concentrations
in the screening and verification programs were identified as
arsenic, thallium, and zinc.
Sultide precipitation is Known to be effective for many
trace metals and a discussion of the treatability of priority
pollutant metals with sulfide is presented in Section 8. During
screening and verification, five plants employing mercury removal
systems were sampled. Table 11-11 presents the priority
pollutant loads found in the treated effluents at four of these
131
-------
TABLE H-9.
RESIDUAL CHLORINE EFFLUENT LOADINGS AT SELECTED CHLOR-ALKALI
PLANTS*
Plant
#207
#014
# 819
# 747
# 106
# 589
# 747**
# 324* *
Average
0.33
0.04
ND
0.002
0.001
0.003
0.0025
3.72
Chlorine Waste Load kg/kkg
Range
1.4 maximum
0 to 1.29
0.016 to 0
0 to 0.006
0 to 0.14
0.001 to 0
ND
0.38 to 12
.14
.011
.2
*See Reference 3
* *From Plant Long Term Monitoring Data
132
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TABLE 11- 10. EFFLUENT LOADINGS FROM SELECTED 'CHLOR-ALKALI MEPCURY CELL
PLANTS*
— — — — — •
Plant
#343
#907
#898
#195
#106
#747
#589
#299
#747**
#317**
#195'**
#324**
Average
0.000025
0.00002
0.00006
0.00004
0.000065
0.000055
0.000055
0.00004
0.000055
0.000006
0.000022
0.00086
Mercury Waste
Maximum Daily
0.00094
0.00026
0.0025
0.00073
0.00022
0.00008
0.00086
0.00019
0.000083
0.000048
0.00066
0.0022
Load kg/kkg
Maximum 30-day Average
0.00029
0.00003
0.00043
0.00015
0.000096
0.000067
0.00049
0.000056
0.000065
0.00001
0.0001
0.0018
*See Reference 3
**From Plant Long Term Monitoring Data
133
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TABLE 11-11. EFFLUENT PRIORITY POLLUTANT LOADS FOLLOWING MERCURY
TREATMENTT k.g/kkg*
POLLUTANT
Antimony, Sb
Arsenic, As
Cadmium, Cd
Chromium, Cr
Copper, Cu
Lead, Pb
Nickel, Ni
Silver, Ag
Thallium, Tl
Zinc, Zn
Flow (m /kkg)
#747
< 0.059
< 0.002
0.032
< 0.011
< 0.006
0.016
< 0.011
< 0.0035
< 0.01
< 0.006
0.23
PLANT
#106
1.6
< 0.015
< 0.039
< 0.028
0.15
1.052
0.40
0.72
0.71
< 0.23
2.8
#317
< 0.10
< 0.008
< 0.01
< 0.02
< 0.012
0.07
< 0.028
< 0.006
< 0.1
0.21
0.41
# 299
0.22
0.092
0.11
0.09
0.055
< 0.074
< 0.074
0.022
0.3
0.15
1.5
tesults of verification sampling 3 days.
2
Indicates effluent load higher than influent load.
* Note: loads are in g/kkg.
134
-------
plants.
Base Level Performance Characteristics for BPT Pollutant Removal
Table 11-12 presents effluent
implementation of BPT or Level 1
mercury cell chlorine plants.
quality achievable through
treatment technologies for
Base Level
Removal
Performance Characteristics for Priority Pollutant
Also presented
effluent qualities
Not included are
organics. Although
anticipated that
in Table 11-12 is the estimated achievable
for priority pollutants with BPT technology.
estimates for tne removal of chlorinated
only limited data are available, it is not
chlorinated organics will be reduced
significantly with BPT treatment,
Pretreatment Applications
Several chlor-alkali plants presently
of their process waste water to POTWs.
chlorine process wastes which require
mercury, lead, and cnlorine. In addition,
suspended solids is required.
discharge all or part
Pollutants present in
pretreatment include
some control of pH and
On the basis
application of BPT
is also recommended
of the effluent quality achievable tnrough the
technology, as presented above, BPT technology
for pretreatment.
11.2.3 Estimated Performance of Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
The advanced treatment performance estimates presented below
include estimates for chlorine discharges. Although this
parameter was not regulated in previous guidelines, and most
chlorine plants reuse or sail their chlorine-ladenxwaste water,
the technology for chlorine removal has recently been established
tor tiiis subcategory and therefore achievable limitations are
recommended. Table 11-13 presents estimated achievable effluent
quality through implementation or Level 2 advanced technologies.
135
-------
TABLE 11-12 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Chlorine - Mercury Cell
Level of Treatment: 1
Waste Water Flow: 2 m3/kkg
Pollutant
Subcategory
Performance
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Aver Max
Emission Limit
(kg/kkg)
30 day 24 hr
Av e r Ma x
BPT Pollutants:
Total Suspended
Solids, TSS
Mercury, Hg
Proposed Priority
12
2.0 15
30
0.02
2.0
0.05 0.10
0.03 0.06
0.0001 0.0002
Pollutants:
Arsenic, AS
Thallium, Tl
Zinc, Zn
(2)
0.04 2.0 0.05 0.10 0.0001 0.0002
(2)
0.3 4.0 0.2 0.8 0.0004 0.0016
(2)
0.5 4.0 0.2 0.8 0.0004 0.0016
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Verfication Sampling
136
-------
TABLE 11-13 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Chlorine - Mercury Cell
Level of Treatment: 2
Waste Water Flow: 2 m3/kkg
Poll utant
Tr eatabil ity
(mg/1)
(1)
T rrri n
Vr K
Quality Limit
(mg/1)
30 day 24 hr
Av e r Ma x
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
BPT Pollutants:
Total Suspended
Solids, TSS
Mercury, Hg
Total Residual
Chlorine, C12
15
2.0
0.02 2.0
0.2 2.0
15
0.2
30 0.03 0.06
0.01 0.02 0.00002 0.00004
0.4 0.0004 0.0008
Proposed Priority
Pollutants
Arsenic, As
Thallium, Tl
Zinc, Zn
0.04 2.0
0.3 4.0
0.5 4.0
0.05 0.10 0.0001 0.0002
0.2 0.8 0.0004 0.0016
0.2 0.8 0.0004 0.0016
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
137
-------
New Source Applications
Examination of the waste water control and treatment
alternatives applicable to new chlor-alkali facilities has led to
the following conclusions:
All new sources should incorporate metal anodes rather than
grapnite anodes. All new sources should provide for alternative
uses or provide for decomposition of chlorine-bearing wastes.
mercury cell plants should provide treatment equivalent to
BPT.
Response to Remand Issues
Zero-discharge limitations originally proposed for
Ciller-alkali plants were remanded primarily because no plant was
snown to achieve zero discharge. The proposed alternative
advanced treatment levels provide for waste water discharge.
11.2.4 Cost Estimates
Discussion
On the basis of the model plant specifications and treatment
system design concepts presented earlier, the estimated control
costs for three production rates at both mercury cell and
diapnragm cell plants are given in Tables 11-14 through 11-16.
Tne costs shown at eacn level of treatment correspond to the
raodel plant BPT system (Level 1) and one or more alternative BAT
systems (Level 2, 3, etc.) which may add to or modify the
existing BPT system to meet more stringent priority pollutant
removal requirements. The BAT systems also provide a higher
effluent water quality with respect to the conventional and
nonconveritional parameters.
Annual treatment cost as a function of production rate is
shown graphically in Figure 11-8. Similarly presented is the
relationship of unit cost (treatment cost per metric ton of
product) to production rate Figure 11-y. The estimated ranges of
total unit costs are shown ana Table 11-17 presents a summary of
the unit cost distribution between amortizacion and operation and
maintenance components.
Summary
Although chlorine manufacture usually produces three wasce
streams, only tiie brine mud aud metal or asbestos contaminated
138
-------
TABLE 11-14 MODEL PLANT TREATMENT COSTS
Subcategory CHLORINE Mercury cell Type of Regulation BAT
Production 19,100 metric tons per year ( 21,057 tons per year)
54 metric tons per day ( 60 tons per day )
Waste water flow 91 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $49,100 $500
Equipment in place,
i ncl ud ing pi pi ng,
fittings, electrical
work and controls 68,100 15,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 25,240 3,100
Incidentals, overhead,
fees, contingencies... 25,240 3,100
Land 21,000
TOTAL INVESTMENT COST $197,680 $21,700
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $112,000 $14,000
Energy 1,250
Chemicals 500 1,400
Maintenance 17,668 2,170
Taxes and insurance... 5,930 651
Residual waste
disposal 4,400
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $156,748 $25,721
C. AMORTIZATION OF
INVESTMENT COST $28,745 $3,530
TOTAL ANNUAL COST $185,493 $29,251
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
139
-------
TABLE 11-15 MODEL PLANT TREATMENT COSTS
Subcategory CHLORINE Mercury cell Type of Regulation BAT
Production 95,500 metric tons per year ( 105,288 tons per year)
272 metric tons per day ( 300 tons per day )
Waste water flow 455 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $134,500 $1,000
Equipment in place,
including piping,
fittings, electrical
work and controls 141,300 61,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 56,960 12,400
Incidentals, overhead,
fees, contingencies... 56,960 12,400
Land 63,000
TOTAL INVESTMENT COST $461,720 $86,800
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $112,000 $14,000
Energy 3,700
Chemicals 2,500 7,000
Maintenance 39,872 8,680
Taxes and insurance... 13,851 2,604
Residual waste
disposal 21,400
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $208,323 $39,784
C. AMORTIZATION OF
INVESTMENT COST $64,871 $14,122
TOTAL ANNUAL COST $273,194 $53,906
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
140
-------
TABLE H-16 MODEL PLANT TREATMENT COSTS
Subcategory CHLORINE Mercury cell Type of Regulation BAT
Production 191,000 metric tons per year ( 210,577 tons per year)
545 metric tons per day ( 601 tons per day )
Waste water flow 910 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $257,700 $2,000
Equipment in place,
including piping,
fittings, electrical
wrk and controls 213,200 115,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 95,980 23,400
Incidentals, overhead,
fees, contingencies... 95,980 23,400
Land 123,000
TOTAL INVESTMENT COST $794,860 $163,800
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $112,000 $14,000
Energy 6,400
Chemicals 5,000 14,000
Maintenance 67,186 16,380
Taxes and insurance... 23,845 4,914
Residual vaste
disposal 42,600
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $272,031 $56,794
C. AMORTIZATION OF
INVESTMENT COST $109,311 $26,650
TOTAL ANNUAL COST $381,342 $83,444
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
141
-------
500
400
2 I /
JZL
o
o
o
X
•w-
H
O
JSL
\A
JXl LBV:CLJ ffi i
I i i
17
300
M7T
M.
i i
z
zz:
z
zoo
J u
100
_L
Figure 11-8.
50 100 150 ZOO
PRODUCTION, METRIC TONS/YEAR X 1000
Annual treatment cost vs. production for the Chlorine
Subcategory (Mercury Cell Process)
142
-------
12
10
2
O
H 8
W
i\
#2!
50 100 150 200
PRODUCTION, METRIC TONS/YEAR X 1000
i i !
Figure 11-9. Annual unit treatment cost vs. production for the Chlorine
Subcategory (Mercury Cell Process)
143
-------
TABLE 11-17 MODEL PLANT TREATMENT COSTS
Subcategory CHLORINE Mercury cell
Type of Regulation BAT
Annual Treatment Costs ($/kkg)
LEVEL OF TREATMENT
PRODUCTION FLOW FIRST SECOND THIRD FOURTH
(kkg/yr) (m3/day) $ $ $ $
Annual Operation
and Maintenance
Annual
Amortization
Total Cost
19,100
95,500
191,000
91
455
910
8.21
2.18
1.42
1.35
0.42
0.30
19,100
95, 500
191,000
19,100
95,500
191,000
91
455
910
91
455
910
1.50
0.68
0.57
9.71
2.86
2.00
0.18
0.15
0.14
1.53
0.56
0.44
Applicable
144
-------
wastes are considered as contributing to waste flows and
treatment costs. Tail gas scruDber wastes, typically high in
sodium hypochlorite, are usually sold or returned to process, and
are therefore excluded from waste flows and waste treatment costs
for tne model plants. however, for the range of annual
production in metric tons from 31,850 to 190,750, the annual cost
of decomposition of sodium hypochlorite varies from 91.26 to
$4.30 per metric ton of product (3).
The chlorine subcategory is a multi-product industry, since
caustic soda is a by-product of chlorine manufacture by either
process. In this report investment costs and annual costs are
expressed in terms of treatment cose per metric ton of chlorine
production, without considering tne production or value of the
by-product caustic soda.
In this report brine mud is presumed to be left on-site in
accordance witii current practice at many chlorine plants. For
neutralization, it is assumed tnat waste sulfuric acid is
available at the plant at no cost.
mercury cell base level bPT costs - waste treatment cost
summary sheets for three chlorine production rates by the mercury
cell process are included as Tables 11-14, 11-15 and 11-16
respectively. Base level costs are shown as the fcirst Level of
treatment. Tne unit costs of BPT treatment per metric ton of
chlorine production are stiown in figure 11-19 as the lower curve
marked Level 1, Mercury Cell, varying from $1.92 to $9.44 per
metric ton.
Mercury cell advanced level coses - waste treatment cost
summary Tables 11-14, 11-15 and 11-16 show incremental advanced
level costs in the column marked •'second". The unit costs of
advanced treatment per metric ton of cnlorine production, which
includes both first and second level costs, are shown by the
middle curve (Level 2) of Figure 11-9, varying from $2.25 to
$10.84 per metric ton.
11.3 ASSESSMENT OF THE WATER POLLUTION POTENTIAL - DIAPHRAGM CELL
11.3.1 Industry Profile and Analytical Results
Chlorine - Diaphragm Cell Plants (Metal Anode)
Tne industrial profile data tor this industry is given in
Taule 11-18 and existing regulations in Table 11-2.
Tne priority pollutants found in the raw waste during
sampling at Chlorine-Diaphragm Cell - Metal Anode plants were as
145
-------
TABLE 11-18 -
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
GHLORTNE DIAPHRAGM CELL
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
8,272,600 kkg/year
6,427,000 kkg/year
45
19
6,397,000 kkg/year
4,200,000 kkg/year
77 percent
66 percent
14,700 kkg/year
1,500,000 kkg/year
221,000 kkg/year
103,000 kkg/year
67 percent
4 years
74 years
1,100 cubic ineters/day
7,100 cubic meters/day
1 cubic meters/kkg
23 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
146
-------
follows:
Maximum Concentration Observed
Pollutant
Screening
Verification (4 Plants)
Chromium
Copper
Lead
Nickel
Mercury
Thall ium
Antimony
Arsenic
Cadmium
Selenium
Zinc
940
525
255
54400
9
14
20
10
2
<9
24
18750
16650
2000
22100
347
<2
43 Found at one
plant only
660
62
93
4290
A summary of daily and unit product raw waste loads for all
plants sampled can be found in Table 11-19. Individual plant raw
waste loads per unit product found in sampling can be found in
Table 11-20. Table 11-20A summarizes asbestos sampling results
at three facilities.
Based on the total annual production of this subcategory and
the average waste load generated per unit product, the estimated
total priority pollutant raw waste loads generated each year for
this subcategory are as follows:
Pollutant
Vvaste load (kg/year)
Chromium
Copper
Lead
Nickel
Me r c u r y
Arsenic
Cadmium
Selenium
Zinc
6100
2600
270
4100
8.
36
21
26
1500
4
147
-------
TABLE 1 1- 19. SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
SUBCATEGORY
Pollutant
Priority
Arsenic, As
Cadmium, Cd
Chromium, Cr
I-
^
oo Copper, Cu
Lead, Pb
Nickel, Ni
Zinc, An
Mercury, Hg
Selenium, Se
Antimony, Sb
Thallium, Tl
Classical
CHLORINE-DIAPHRAGM CELL WITH METAL ANODES
Minimum
0.000038
0.00034
0.0036
0.0037
0.00086
0.013
0.017
0.00018
0.00023
7.39
Loadings
kg/day
Average Maximum Minimum
0.0021 0.0033 0.00000015
0.0015 0.0029 0.000001
0.58 2.81 0.000015
0.12 0.27 0.000011
0.021 0.064 0.0000037
0.28 0.88 0.00004
0.08 0.17 0.000057
0.00053 0.00082 0.0000003
0.0016 0.003 0.000003
0.00064
0.000045
kg/kkg
Average
0.0000056
0.0000033
0.00095
0.00041
0.000042
0.00064
0.00024
0.0000013
0.000004
0.000003
0.0000002
No. of Plants
Maximum Averaged
0.000014 5
0-000006 5
0.0046 5
0.0012 5
0.000095 5
0.0014 5
0.0007 4
0.0000025 3
0.000005 2
1
1
TSS
23.8
53.9
0.026
0.069
0.18
-------
TABLE 11-20. PRIORITY POLLUTANT RAW WASTE LOADS (in kg/kkg of Product)
SUBCATEGORY
CHLORINE - DIAPHRAGM
POLLUTANT
#014
#261
PLANT
#736
#?38Cold) #738(new)
Chromi-um, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel, Ni
Selenium, Se
Thallium, Tl
Zinc, Zn
Antimony, Sb
Arsenic, As
Cadmium, Cd
0.000015 0.000073 0.000044
0.000011 0.00064 0.0012
0.000004 0.000077 0.0000037
0.0000025
0.00083 0.00085 0.000056
0.0000002
0.000057 0.0007
0.000003
0.00000015 0.000006 0.000014
0.0000014 0.000001 0.000006
0.0046 0.00004
0.00011 0.0001
0.00003 0.000095
0.000001 0.0000003
0.0014 0.00004
0.000005 0.000003
0.00009 0.0001
0.000004 0.000004
0.000004 0,000004
*Does not include brine muds.
149
-------
TABLE 11-20A. RESULTS OF ASBESTOS SAMPLING AT DIAPHRAGM CELL PLANTS
Plant Stream
#261 Supply
Cell Wash
Filtered Discharge
Barometric
Condenser
#736 Supply
Cell Wash
Cell Room Waste
Barometric
Condenser
Barometric
Condenser
Barometric
Condenser
# 967 Supply
Cell Waste
Pond Effluent
Caustic Wash
Brine Filter
Backwash
Cathode Wash Waste
Condensate & Spent
Acid
Neutralizer Waste
Total Asbestos
Fibers (MFL)*
8.0
2.1 X 108
1.6 X 103
0.4
0.7
2.0 X 107
2.9 X 102
1.8
5.3
1.4 X 102
9.7 X 102
2.4 X 104
2.4 X 103
7.8 X 103
8.0 X 102
3.2 X 105
2.7 X 102
2.1 X 103
Chrisotile
MFL
7.5
2.1 X 108
1.6 X 103
0.4
0.7
2.0 X 107
2.8 X 102
0
5.3
1.4 X 102
9.7 X 102
2.4 X 104
2.4 X 103
7.8 X 103
6.2 X 102
3.2 X 105
1.8 X 102
2.1 X 103
Amphibole
MFL
0.4
0
0
0
0
0
8
1.8
0
0
0
8 X 102
0
0
1.8 X 102
0
8.9 X 10
0
*Million fibers per liter
150
-------
Chlorine-Diaphragm Cell Plants (Graphite Anode)
The industrial profile data is included
existiny regulations in Table 11-2.
in Table 11-5 and
The priority pollutants found in significant concentrations
in the raw waste during screening at Ciilorine-Diaphragm Cell -
Graphite Anode Plant #967 were as follows:
maximum
Pollutant
Concentration
ug/1
Lead
Antimony
Chromium
Zinc
Copper
Mercury
Arsenic
Cadmium
Nickel
Qrganics
benzene
Carbon Tetracnloride
1,2-Dichloroethane
Hexachloroethane
Chloroform
Dichlorobromomethane
Bis(2-ethylhexyl) phtnalate
Tetrachloroethylene
1,631,000
1910
300
3204
7450
74
680
46
640
15
197
621
90
691
309
120
196
A list of daily and unit product raw waste loads for the
priority metals found at Plant #967 can be found in Table 11-21.
A list of daily and unit product raw waste loads for
organics found at Plant #967 can be found in Table 11-22.
the
The major waste stream source of organic priority pollutants
was the chlorine header condensate stream. The neutralizer waste
stream was the second largest contributor of organics.
All of
0.45 kg/day
at nonsignificant levels.
the organic priority pollutants found greater than
were volatile organics. The remaining organics were
Total priority pollutant waste loads for this subcategory
division cannot be calculated at this time because it is not
known how many graphite anode plants there are, and the total
annual production value is also not available.
151
-------
TABLE 11-21,
METAL PRIORITY POLLUTANT RAW WASTE LOADINGS FOUND IN SAMPLING
AT A CHLORINE-DIAPHRAGM CELL PLANT WITH GRAPHITE ANODES
Pollutant
Priority
Chromium, Cr
Copper, Cu
Cadmium, Cd
Lead, Pb
Mercury, Hg
Nickel, Ni
Zinc, Zn
Antimony, Sb
Arsenic, As
kg/day
Average
0.057
0.42
0.00091
60.0
0.005
0.12
0.12
0.058
0.60
PLANT #967
Loadings
kg/kkg
Average
0.00026
0.0019
0.000004
0.273
0.000022
0.00054
0.00054
0.00026
0.0028
152
-------
TABLE H-22.
ORGANIC PRIORITY POLLUTANT RAW WASTE LOADINGS FOUND IN
SAMPLING AT A CHLORINE - DIAPHRAGM rET.L PLANT WITH GRAPHITE
ANODE
Pollutant
Benzene
Carbon Tetrachloride
1, 2-Dichloroethane
Hexachloroe thane
Chloroform
Dichlorobromomethane
Hexachlorobutadiene
Bis ( 2-ethylhexyl) phthalate
Tetrachlorothylene
PLANT #967
Loadings
kg/day
Average
0.00091
0.066
0.23
0.03
0.24
0.10
0.011
0.0023
0.10
kg/kkg
Average
0.000004
0.0003
0.001
0.00014
0.0011
0.00046
0.00005
0.00001
0.00046
153
-------
11.3.2 Process Waste Sources
General Process Description
Diaphragm Cell Process - The sodium chloride (uJaCl) solution
(brine or salt dissolved in water) is purified before it is sent
to the diaphragai cell for chlorine, caustic and hydrogen
production. This is done by the addition of soda ash (Na2C03)
and small amounts of caustic soda until the ph increases to 10 or
11. Tue calcium and iron present in the brine and trace amounts
of otner metals are precipitated as hydroxides or carbonates, and
tne brine is sent to a clarifier for solids separation. The
underflow from the clarifier, Known as brine mud, is sent to a
layoon or is filtered. The overflow from the ciarifier, which is
brine, is neated and brought to saturation by the addition of
salt recovered from the caustic evaporation. The pH is then
lowered to 6 by addition of HC1 before introducing it to the
diaphragm cell.
The saturated salt solution (26 percent concentration) is
electrolyzed in the diaphragm cell to form chlorine, hydrogen,
and sodium hydroxide according to the reaction:
2NaCl + 2H20 = C12 + 2NaOti + i-i2 (1)
In one pass tnrough the cell, the salt solution is
decomposed to approximately naif of its original concentration.
The diaphragm cell contains a porous asbestos diaphragm
separating the anode from the cathode. Chlorine is liberated at
the anode and the hydrogen and caustic are produced at the
catiiode. In tiie past, the predominant material used for anodes
was graphite with lead used to provide an electrical contact and
support. The lead is joined to the graphite anode by an organic
binder. In recent years, the majority of graphite anodes have
been changed to stabilized metal anodes, made of titanium with a
platinum or rubidium oxide coacing. The advantages of using
metal anodes compared to grapnite anodes are increased current
efficiency, dimensional stability and a lower chlorine
overvoltage, as well as a reduction in the quantity of waste
water produced. The use of aietal anodes also reduces or
eliminates the chlorinated orgauics and lead impurities in the
wasce waters. The cathodes in the diaphragm cells are usually
Hollow steel screens witii a coauing of asbestos deposited on the
outside.
The hydrogen from tne top of the cathode is cooled to remove
water and other impur isies, and it either sold, vented to tiie
atmosphere or burned to produce steam. Tne caustic leaving the
catnode has a concentration oi; 11-12 percent iMaUti. It is
154
-------
concentrated by multiple effect evaporation to increase the
concentration to 50 percent. Tiie vapor evolved from the last
effect of the evaporator is air condensed in direct contact with
water using barometric condensers, or in surface condensers,
using noncontact cooling waters. when barometric condensers are
used, the amount of waste water produced by this operation is
large. During evaporation, salt crystallizes and is removed from
all the evaporators. The concentrated caustic is then settled
and filtered to remove the residual salt wnich is recycled to
tne brine preparation stage.
The chlorine from tne cell is cooled to remove water and
other impurities. The condensates are eitiier discharged without
treatment or recycled to the brine purifier after steam stripping
for chlorine recovery. The chlorine gas, after cooling, is
scrubbed with concentrated sulfuric acid to remove water. This
is done in a series of towers wnere tne acid flow is counter to
that of the cnlorine gas. Tne acid is used until a constant
dilution is reached. The spent acid is either regenerated, used
on site or is sold. Figure 11-10 is a general flow diagram for
tne manufacture of chlorine/caustic using diapnragm cells.
Water Use and Waste Source Inventories
In the diaphragm cell, a large quantity of water is used in
tne barometric condensers if the vapors from the caustic
evaporators are contact cooled. Table 11-23 is a summary of the
water usage in the barometric condensers for a few plants where
data are available. tor plants practicing contact cooling
through barometric condensers, tne average amount of water usage
is twice that of tne mercury cell plant per metric ton of
cnlorine produced. The range of water usage in a diapnragrn cell
is 15 to 492 cubic meters per metric ton of chlorine. Of the
total water usage in diaphragm cell plants, approximately 50
percent is used for noncontact cooling. In addition, the amount
of water used for cleaning diapnragm cells is higher than that
of mercury cells.
Barometric Condenser Water - The waste water specific to the
diapnragm cell process is the barometric condenser water. A
significant amount of water is used in contact cooling the valors
from the evaporators used to concentrate the caustic. In the
mercury cells, the caustic comes out at a concentration of 50
percent and does not require evaporators unless a caustic of high
concentration (e.g., 73 percent) is required. Tne barometric
condenser waste water ranges from d9 to 191 cubic meters per
metric ton of chlorine. Tne barometric condenser waste water is
either discharged without treatment, or recycled and a bleed is
discharged with or without ph adjustment.
155
-------
LIME
BRINE
1
SULFATE SAL
PURGE
NC
NCONTACT
COOLING -^
WATER ^
11%
i
T RECYCLE
Ln
Ch COOLING
TOWER**
t
BLOWDOWN
TO WASTE
WATER
LEAKS,
SPILLS
WASIIDOWN
ETC.
t
TO WASTE
PURIFICATION
SYSTEM
1
DIAPHRAGM
CELL
DRINE MUDS ^TO HA^TE NONCONTACT COOLING WATER
i *
COOLER OR USE
CHLORINE ^— ^— —
TO 12% SODIUM *
HYDROXIDE
SOLUTION
t
EVAPORATOR
COOLING
WATER
WATER _ ^
, 1^™"^^^^
BAROMETR TC" ^^^
CONDENSER COOLER ^" (JIll^UKlNATKU WATHK CONDENSATE
t t *
-
SALT
REMOVAL
1
SODIUM
HYDROXIDE
SOLUTION
1
FILTER
^ (LIME) ^ j|k
1 AND WATER SODIUM
SOLUTION SALES, OR WASTE
*
REFRTfifiP- TAIL GAS wm-r-n
ATION LIQUEFIER «
SYSTEM "* i * 1
¥ t 4 1 DIAPHRAGM
PACKAGING
TO USE
OR SALES
NONCONTACT LIQUID WASHING
COOLING CHLORINE &
WATPP WATFD DEPOSITION
TO SALES
OR USE T0 WASTE
USED SOME PLANTS ONLY
DEPENDS UPON PLANT DESIGN
Figure 11-10General process flow diagram for production of chlorine/caustic by diaphragm cells.
-------
TABLE 11-23. DATA OF WATER USAGE FOR BAROMETRIC CONDENSER IN CHLORINE/
CAUSTIC PLANTS USING DIAPHRAGM CELLS
Plant Water usage ra /kkg of Cl~
#207 115
#858 89
#736 191
157
-------
Discharges from the barometric condensers contain some salt
and caustic as a result of the carryover from the caustic
solution. when grapnite anoo.es are used, the barometric
condenser waste water contains lead.
Sulfate Purge waste Water - During concentration of the
caustic by evaporation, sodium chloride precipitates out. The
salt is removed and is washed with water to remove sodium
suifate. A portion of wash water is recycled and the rest is
purged to waste in order to stop the buildup of sulfates. The
stream is one of the major sources of waste water from
chlorine/caustic plants using diaphragm cells.
Control and Treatment Practices
Diaphragm Cell Plants Visited and Sampled
Waste water streams were sampled and analyzed for priority
pollutants in the screening and verification phase of the
sampling program. Tne waste water streams at Plant #014 were
sampled during screening, while Plants #261, #738, #967 and #736
were sampled in tiie verification phase.
At Plant #014, the chlorine condensate is stripped with
steam to remove and recover chlorine. The brine precipitates
(muds) are land disposed, while the spent sulfuric acid and
scrubber solutions are used at an adjacent plant. The condensate
from the hydrogen cooler is used as makeup water for a cooling
tower system, and the condensate from the evaporative
concentration of sodium hydroxide is used to dissolve salt
reclaimed from the concentration process. The cell washings
are sent to a collection pond where asbestos and otner suspended
solids are removed. In Figure 11-11 the general process flow
sheet is presented. The waste streams sampled and their waste
loadings are given in Table 11-24.
At Plant #261, the cathode wash water is passed through a
filter and the asbestos is disposed of in a landfill while the
filtrate goes to the sewer. The caustic liquor from the cells
goes to multiple-effect evaporators. The water vapor from the
evaporators is sent to a barometric condenser from wnich waste
water is produced. The caustic and salt are botn concentrated
further. irigure 11-12 shows the process flow diagram and all
sampling points. Table 11-24 gives waste stream flows arid
loadings.
Plant #738 has two production lines, 738A and 738b, that are
almost identical. At the new plant (73Uc>), tiiere is no
concentration of the NaUH to 73 percent strengta nor is the waste
from tiie chlorine disposal system scrubbed. Also, the inert
gases from the liquefaction step are put through the chloride
158
-------
VENT GAS
U1
TAIL GASES
a
BRINE ~_
1
RINE MJD
1
SALT
RETURN
CELL ROOM
i
ci2
1C
WASTE COOLING
WATER »3
Naai
NaOH
EVAPORATION
1
!
\.&*J ^ ChJ .1 1 WftbH
Hqy*'
14
ran
1
(XOLING
«
!
1
50
^ REUSE 75% H2SO4 COOLING WATER
CONDENSATE
NaOH FUSION
^"REUSED
C12 IN
PIAOT
Cl^
BAROMETRIC
CONDENSER
WATER TO
WASTE.
NaOH
TO WASTE
t
CMNDENSER
WATER TO
HASTE
•
f
B^M
Sampling points.
NaOH
Figure 11-11. General process flow diagram at Plant iOOl. showing the sanpling points.
Chlorine/Caustic (Diaphragm Cell) Manufacture
-------
H-24 FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE STREAMS
FOR PLANTS #277, #261, AND #738 PRODUCING CfflLORINE/CAUSTIC
BY DIAPHRAGM
Plant
#277
#261
#738
#738
Sampled Stream
Stream Description
NO.
3
4
5
6
1
2
3
4
5
1
2
3
4
5
6
7
8
9
Chlorine
Condensate
Cell Wash
Brine Mud
Flow
nP/kkg
of C12
0.9
0.015
0.018
Barometric 306
Condensate
Brine Mud
Cell Wash
Asbestos
Filtrate
Asbestos
Filtrate Cake
Barometric
Condenser
Cell Room
Waste
Asbestos Wash
Scrubber (Hypo)
Chlorine
Cooling
Water (H2SO4)
0.832
0.384
NA
NA
NA
0.0682
0.165
0.124
0.478
Caustic 249.1
Cooling Tower
Cell Room
Waste
Asbestos Wash
Scrubber (Hypo)
Chlorine
0.0589
0.142
0.107
0.413
SS
Load
kg/kkg
of C12
1.35 x 10~3
0.024
NA
3.64
NA
0.183
(9 mg/1)*
NA
(6 mg/1) *
1.4 x 10"3
8.4 x 10~3
3.5 x 10"2
1.4 x 10~2
10.48
5.3 x 10~3
9.4 x 10~3
1 x 10~2
5.7 x 10~3
Pb
Load
kg/kkg
Of C12
4.95 x 10~6
3.9 x 10~6
1.3 x 10~5
1.5 x 10~3
2.88 x 10~4
0.100
(0.075 mg/1)*
(42.4 mg/1)*
(<0.01 mg/1)*
5.25 x 10~6
5.15 x 10~6
1.88 x 10~5
9.9 x 10~6
0.127
1.97 x 10~6
1.62 x 10~5
2.4 x 10~5
8.04 x 10~5
Asbestos
Load
kg/kkg
of C12
NA
NA
NA
NA
0.117
0.07
(0.14 mg/1)*
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Cooling
Water (H2S04)
160
-------
TABLE 11-24 continued
Plant Sampled Stream
Flow
Stream Description rn^/kkg
No
#738 10
11
12
13
14
.
Caustic
Cooling Tower
Chlorate Sump
Plant Effluent
Final Effluent
(Total)
Brine Mud
of C10
£
215.1
0.28
0.46
NA
NA
SS
Load"
kg/kkg
of C12
1.0
0.009
0.028
*
(64 mg/1)
c
(2.70 x 10*
PB"~
Load
kg/kkg
of C12
<2.2 x 10~3
<2.8 x 10~6
5.3 x 10~5
*
(1078 mg/1)
*
(<0.01 mg/1)
Asbestos
Load
kg/kkg
of C12
NA
NA
NA
NA
NA
A = Not Available
Flow of the sampled stream is not available so the concentration is given
in mg/1.
161
-------
SODIUM
CARBONATE
RAW
BRINE
CTl
NJ
NaOlI
SALT
WDROGEN TO BOIU5R
ILING WATER
MIXERS
CLARI-
FLOCCULATORS
SAND
FILTERS
BRINE MUDS
ADJACENT HANT
H2S04
r
SLUDGE TO LANDFILL
COOLING WATER
FILTRATE TO
PROCESS SEWER
ASBESTOS TO
LANDFILL
TO
EJECTOR
*
SPENT H2S04
C12
WRTE
H
r^
RJRIFICATION
BOTTOM TOWER
(
HJRIFICATION
TOWER
LIQUEFIER
1
RIRGE FOR DISPOSAL
BY CONTRACT
BRINE RECYCLED
TO PROCESS
HYPOCHLORITE
SOLUTION TO
ADJACENT PLANT
CHLORINE AND RAILROAD CAR
TO STORAGE WASHDOWN
IWaste streams sampled.
NaOH
TO BOII.KR
FEED WATER
. TO SLAKE LIME
(FOR LIME PLANi
-*• PROCESS SEWEB
It) EJECTOR
PROCESS
SEWER
Figure 11- 12. General process flow diagram at Plant 0261 showing the sanpling points.
Chlorine/Caustic (Diaphragm Cell) Manufacture
-------
disposal system. Table 11-24 shows the sampled waste streams and
their loadings for both plants. The process flow sneets are
shown in figure 11-13 and 11-14.
Plant #967 uses graphite anodes in its diaphragm cells. The
cell washings at this plant are sent to an asbestos pond that has
a continuous cover of water. Periodically, the settled solids
are removed, sealed in drums and disposed of in a landfill. The
overflow from the pond is treated with soda asn to precipitate
lead, and then with sulfuric acid to bring the pri down to 6-9
range. It is then finally settled. Table 11-25 shows the waste
streams sampled and waste loadings for this plant. figure 11-15
is a general process flow diagram for Plant #967.
Plant #736 has installed de-raisters to control the vapors
evolved from the last stage of the evaporator during the
concentration of caustic. In this treatment, the steam evolved
from the concentration of cell liquors passes through metal wool
filters to reduce entrained solids. The cell room washings are
sent to a settling chamber and the settled asbestos is sent to a
landfill. The other waste waters, consisting of caustic
evaporator washings and wastes from salt separation, brine
purification operations, and caustic filtration backwash waters,
are combined and sent to one of two settling ponds. Skimming
devices on the settling ponds remove any oil that separates,
while the settled solids in the ponds are dredged and disposed of
in an abandoned brine well. Figure 11-16 shows the process flow
diagram and sampling points. Table 11-25 gives the pollutant
loadings of the streams sampled.
Treatment Practices-Diaphragm cell - Waste water treatment
practices are available for few plants. Unless otherwise
specified, the plants described use metal anodes in their cells.
At Plant #999, the brine mud and other suspended solid
streams are collected and filtered in leaf filters. The cake is
disposed of in a landfill and the brine filtrate returned to the
brine system.
At Plant #326, the waste water from chlorine diaphragm cell
plants is combined with other process waste waters. The combined
waste water is sent to the first of two settling tanks in series.
In one of the settling tanks, skimmers have been installed
to remove oil and the overflow from the second is filtered before
di scharge.
At Plant #589, the brine mud from the clarifier underflow is
sent to a brine mud settling pond. The overflow, which is mostly
brine, is returned to the process. The cell room washings are
sent to a settling pit and the settled asbestos fibers are
removed by the use of a vacuum truck, and disposed of in a
163
-------
1-
cn
BRINE
73% NaOH
HJRIFICATION
AND
COMPRBSSION
LIQUEFACTION
"Cl.
•-WASTE HYDROCARBONS
SPENT
H2S04
O
BAROMETRIC H2O
Sampling points.
WASTE SUMP
VENT
WASTE WATER
(NaOCl +
(Point 112 - waste soap (combination of all wastes).)
Figure 11-13. General process flowsheet at Plant ((738 showing the sanpling points.
Chlorine/Caustic (Diaphragn Cell) Manufacture
-------
cn
BRINE
H2° H2°
* I
COOLING
WASTE-*— TOWER -|
t r
r „„ Y
BRINE - • •
PURIFICATION BRINE p^j.
AND ROOM
** RESA1URATION
H
BRINE u fTT.|.
MUD WASH
AND
COOLING
AND
COMPRESSION
'S*
WASTE H-O
C12 _
16
_., _.J go
n
H2 LUIE to, 2 f^) to» WASTE
— fi» (CAUSTIC)"" DISPOSAL V^/ HYPOCIBjORITE
H20 H2S04 , , .^^^^
i *
COOLING AND ^-^to» PURIFICATION ^2^ LIQUEFACTION
DRYIN3 COMPRESSION
1 ' H2SO4 HYDROCARBONS
WASH H2°
. *7
ASBESTOS f&\ fa&
PANEL ^^/ v3*
M
COOLING i r V -^
4 ' '
V"W Sampling points.
WASTE
Figure 11-14. General process flow diagram at Plant 1738 showing the sampling points.
Clilorine/Caustic (Diaphragm Cell) Manufacture
-------
T3\ELE 11-25 FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANTS #9 6 7 AND #7 3 6 PRODUCING CHLORINE BY DIAPHRAGM CELL
Plant Sampled Stream Flow
Stream
No.
1967 1
2
3
4
5
6
#736 1
2
Description nrykkg
of Cl,,
^
Cell Building 0.18
Wastes
Lead Pond 0.55
Effluent
Caustic Plant 5.38
Effluent
Brine Filter 0.45
Back Wash
Cell Wash 0.18
Condensate And 0.79
Spent H2S04
Cell Wash 0.652
Cell Room 0.0163
SS
Load
kg/kkg
of Cl,
2
0.187
0.03
0.841
5.75
0.05
0.85
0.06
4.62 x 10~3
Pb
Load
kg/kkg
of Cl,
2
0.12
0.016
0.014
-4
2 x 10
8,6 x 10~3
-4
7.3 x 10
9.1 x 10~7
2.75x 10~6
Asbestos
Load
kg/kkg
of Cl,
2
7.5 x 10~5
1.56x 10~5
7.6 x 10~4
-6
1.8 x 10
6.6 x 10~4
-6
9.8 x 10
NA
0.085xlO~6
Drain
3 Brine Mud
1.631 32.621
3.1 x 10"
NA
4 50% Barometric NA (32 mg/1)
Condenser
5 70% Barometric NA (20 mg/1)
Condenser
6 95% Barometric NA (90 mg/1)
Condenser
7 Chlorine
Condenser
0.163 3.9 x 10"
(<0.01 mg/1)* (1 x 10~4mg/l)*
(<0.01 mg/1)* (1 x 10~4mg/l)*
( 0.01 mg/1) (4 x
,-6
1.63 x 10"
NA
Flow of the sampled stream is not available so the pollutant concentration
is given as mg/1.
NA = Not Analyzed.
166
-------
BRINE
SALT
DRY SALT
i
H TO POWER HOUSE
SALT TO RECOVERY
COOLING
EQUIPMENT
f
41
FILTERS
£
1
^ 13
SALT TO SEMER
Sampling points.
DISCHARGE
TO ADJACENT
PLANT
Figure 11-15. General process flow diagram at Plant 1967 shewing the saiiplang points.
Chlorine/Caustic (Diaphragm Cell) Manufacture
-------
CLMUFIER
T
13
BRINE MID TO
DEEP WELL
DISPOSAL
FILTER BACKWRSH
TO nRKP WELL
DISPOSAL
HYDROGEN TO ATMOSPHERE
OR CAPTIVE USE
LIQUID
CHLORINE
TO STORAGE
CONTACT WWER
TO RIVER
CONTACT ASBESTOS
WATER TO SOLID
TO RIVER WASTE
DISPOSAL
00
COOTACT
WASTE "WATER
TO PONDS
CHEMICALS
e
Waste streams sampled.
FLAKER
SULFATE
| CEWTRIGUGE
t
t-*-w;
FTTiTRATTrN ... .
t
EULFATE CONTACT WATER
BRINE SLURRY TO SETTLING POND
TO DEEP WELL
DISPOSAL
— ANHYDROUS
•• . \ 7
^TER
0% ^_
CONTACT V1ATER
TO SETTLING PONDS
T
CAUSTIC
SODA
FLRKES
CONCENTRATOR
TOR p n
*6 CAPTIVE
CONCEOTRATOR
USE
(70% CAUSTIC)
ANHYDROUS
CAUSTIC CONTACT WATER
SODA TO SETTLING POND
Figure 11- 16. General process flow diagram at Plant J736showing the sampling points.
Chlorine/Caustic (Diaphragm Cell) Manufacture
-------
landfill. The chlorine from the cells is contact cooled with the
tail gas scrubber water. The resulting waste water is steam
stripped for chlorine recovery before discharge.
At Plant #741, chlorine, caustic soda, and potassium
hydroxide are produced using both mercury and diaphragm cells.
Mercury-bearing effluent at this facility is treated by sulfide
precipitation. Tail gas absorption wastes are treated by
catalytic decomposition by a process which consists of
scrubbing with caustic soda treating solution and treating the
resulting hypochlorite solution with nickel chloride and iron
chloride catalysts. Decomposition proceeds relatively slowly.
Consumption of iron and nickel chloride is approximately equal
and consists of 0.01 kilogram per metric ton of chlorine
produced. Wastes are retained in the treatment tanks for
approximately three days, after which time no residual chlorine
is reported to be present in the discharge (3).
Chlor inated organic hydrocarbons - The use of graphite
anodes, in either mercury cell or diaphragm cell plants, results
in the generation of a variety of simple chlorinated hydrocarbon
compounds as a result of the attack of chlorine on the anodes.
These compounds are carried out of the cell with the chlorine and
find tneir way into the various waste streams which originate
from the chlorine cooling, drying, compression and liquefaction
steps. In cases such as Plant #967 where the end use of the
product chlorine is captive involving its direct application to
the manufacture of a chlorinated organic product, the bulk of
chlorinated organic impurities are not removed from the chlorine.
Table 11-22 shows the raw waste loadings of organic compounds
found in the chlorine condensate waste stream at Plant #967. In a
flow of approximately 320 m3/day, the total organic raw waste
load was found to be 0.78 kg/day. The amount of carbon
tetrachloride alone was 0.066 kg/day at a concentration of
approximately 0.2 mg/1. At Plant #195, where a purified product
is required, the chlorinated organics are accumulated in the
reboiler of the chlorine tracifier (chlorine scrubber). The
tracifier residues are treated batchwise for separation and
recovery of the organic phase materials which are sold as feed
stock for the manufacture of related products. Prior to
discharge, the aqueous phase is vacuum stripped to remove and
recycle additional chlorinated organics and chlorine. Normally,
one batch of organics is treated per week. After separating each
batch of organics and stripping the residual aqueous phase, the
quantity of waste water discharged is approximately 5.7 m3/week
or 0.8 m3/day- The organic loading in this waste is not known,
however, if the assumption is made that the discharge is
saturated with CC14 (800 mg/1 @ 20 degrees C) , the waste load
would be 0-5 kg/day.
Although the daily mass emissions from the two plants are
likely to be similar and both would require additional treatment
169
-------
to achieve acceptable discharge levels, the wide difference in
concentrations of the chlorinated organics as well as the manner
in which they are handled, would necessitate the application of
an advanced treatment technology specifically suited to each
case.
Where the flow is large and the concentrations are low, the
application of activated carbon adsorption to the collected
organic-bearing waste stream at Plant #967 would be capable of
reducing a CC14 mass emission from 0.066 kg/day to approximately
0.03 kg/day, assuming a treatability level of 0.10 mg/1.
In the case of Plant #195, where the volume of waste water
is small but the concentrations of residual chlorinated organics
can be in the order of several hundred ppm, a more appropriate
final removal technology would be steam stripping with an
overhead return to the process. Assuming a treatability level of
10 mg/1 for CC14 using this technology, its mass emission could
be reduced to approximately 0.01 kg/day.
The additional costs for steam stripping in a plant (such as
Plant #195) which already has a vacuum vaporizer, would be under
$10,000 for modification of the existing equipment. Steam costs
could vary from $1,000 to $5,000 per year. If a vaporizer is not
in place, a steam stripper to process 5 to 30 m3/week would cost
roughly $50,000 to $100,000, depending on the input
concentrations to be handled. The corresponding steam costs
would range from $2,000 to $10,000 per year.
The capital costs of an activated carbon adsorption unit for
handling the relatively high volume wastes with a low influent
organic loading (as found at Plant #967) cannot be reliably
estimated in the absence of specific treatability data on the
waste streams in question.
A process evaluation should be made to determine the most
efficient means of isolating and collecting the organic bearing
waste streams prior to treatment.
Alternatively, incineration of the chlorinated organic
residuals is an effective means of destroying and disposing of
this material provided that adequate measures are taken to
control the release of HC1 to the atmosphere.
Evaulation of Industry Production and Waste Flow Data
In the diaphragm cell plants, the waste in many plants is
segregated into four different streams. The brine mud wnich
contains a large amount of suspended solids is either sent to a
lagoon or filtered and the clear liquid recycled for brine
recovery. The solids content in the brine mud was found to vary
170
-------
from 2 to 20 percent. The second segregated waste stream is the
chlorine-contaminated waste water. The third segregated waste is
the cell wash. It includes the waste water from washing Of
cells, cathode wash and diaphragm rebuilding areas, and leaks and
spills in the chlorine cell room. This stream contains asbestos
either in fiber form or stabilized sheets in the waste water.
The last segregated waste stream is Known as the process waste
water. Metals like lead and nickel may 'oe found in small
quantities in this stream. It is a combined waste which consists
of streams like brine and caustic filter backwash, sulfate purge,
etc. A further breakdown of the individual segregated waste
streams is not available. In plants using graphite anodes, this
waste stream contains a significant amount of lead. Table 11-26
gives the flow of the segregated waste streams for plants whose
data are available.
Process Modifications and Technology Transfer Options
Cooling Water - The vapors from the evaporative
concentration of caustic soda (in diaphragm cells) are either
contact cooled or cooled in surface condensers. Plants
practicing contact cooling through barometric condensers generate
large amounts of waste water. The barometric condenser water is
subject to contamination with caustic and salt. By changing from
contact cooling of the vapors to noncontact cooling, the amount
of waste water generated can be reduced considerably. If the
change is expensive or is not feasible, then de-misters or
similar control devices need to be installed to reduce the salt
and caustic carryover in the vapors. Similarly, if a plant has a
barometric condenser on the brine dechlorinator, it can be
replaced with an indirect condenser to achieve a reduction of
waste water and recovery of mercury in a mercury cell plant.
Anode Material - In the majority of cases, in both mercury
and diaphragm cells, the anodes have been changed from graphite
to metal. The use of metal anodes increases the cell current
efficiency and eliminates or reduces considerably the chlorinated
organic compounds and lead in the waste waters. The metal anodes
consist of an expanded titanium metal substrate coated with
precious metal and rare earth oxides.
Diaphragm Material - The use of modified diaphragms produces
beneficial effects in power consumption and environmental
controls. The three modified diaphragms available, polymer
modified asbestos, polymer membrane, and ion exchange membrane,
are discussed briefly below.
A. Polymer Modified Asbestos: This consists of a polymer-
treated asbestos diaphragm baked into place on the cathode. Its
usage results in power savings and has a minor environmental
benefit, since, at the time of rebuilding of the cathodes, the
171
-------
11-26. WASTE FLOW DATA FOR CHLORINE/CAUSTIC SUBCATEGORY USING
DIAPHRAGM CELLS
Stream Description Plant Unit Flow m /kkg of chlorine
Brine mad #858 0.417
#967 0.277
#736 1.68
Cell wash #858 0.084
#736 0.0168
#589 0.05
Tail gas scrubber effluent #858 0.167
(hypochlorite solution)
#967 0.29
#967 0.105
172
-------
discarded material is produced in stabilized pieces instead of
loose asbestos fibers. The disposal is thus safer and easier.
B. Polymer Membrane: This consists of raicroporous teflon-
type polymer, and its operation has been demonstrated
successfully in laboratory and pilot plant scale cells. in
addition to the benefits of cost savings through energy use
reduction and longer life, its use eliminates the handling and
disposal problems associated with asbestos.
C. Ion Exchange Membrane: These membranes allow the
transfer of positive ions to the cathodes and prevent the
transfer of negative ions to the anodes, thus allowing production
of a concentrated caustic similar to that produced by mercury
cells. The production of salt-free concentrated caustic will
reduce the waste water associated with the caustic evaporation
process. Dupont's Nafion is the most successful membrane
available in the United States, and a pilot plant producing 12
tons per day of chlorine is operating successfully using this
membrane. Like the polymer membranes, the problems associated
with the handling and disposal of asbestos are eliminated. Use
and commercialization of the membrane is anticipated in the near
future. The longer life of the membrane will reduce the waste
waters associated with the rebuilding operation.
Model Plant and BPT Treatment Systems Specifications
Diaphragm Cell Plants - The specified BPT treatment for the
chlorine/caustic plants using diaphragm cells consists of:
A. Asbestos removal (from cell washing) by alum
coagulation and settling, followed by filtration
and land disposal of the solids.
B. Partial recycle of the Drine waste stream to process.
C. Lagoon settling of the brine mud and long-term
storage at site.
D. Incidental heavy metal removal resulting from use
of soda ash to promote flocculation.
Currently, about 65 percent of the total chlorine produced
in the United States is made by diaphragm production. Data is
available for 62 percent of the total diaphragm cell
chlorine/caustic producers. The production at industrial plants
ranges from a minimum of about 15,000 kkg of chlorine/yr to a
maximum of 1,500,000 kkg of chlorine/yr. Because of the large
number of plants in tiie subcategory and wide range of production
levels, three model plants with production capacities of 19,100,
95,500 and 191,000 kkg of chlorine/yr were selected to represent
173
-------
the production range of plants for
flow per unit of production remains
which data is available. The
the same for each model.
A. Waste Water Flow: The waste streams are segregated into
brine mud, cell wash and process waste. The brine waste is
settled in ponds and the overflow is recycled to the process.
Tne unit brine mud flow was taken as 0.42 m3/KKg of chlorine
containing 10 percent suspended solids. The cell wash, which
includes the wash waters, leaKs and spills from the cell rooms,
is sent to a holding tank and is mixed with the other process
waste water for metal treatment and pH adjustment. Tne cell wash
is segregated because it has asbestos as suspended material in
it. The asbestos content was taken as 0.825 kg/kkg in the cell
wash. A unit cell wash flow of 0.07 m3/kkg of chlorine was taken
for the model plants. The process waste water stream, which
includes the brine and caustic filter backwash, sulfate purge
liquid, etc., was taken as 0.77 m3/kkg of chlorine produced.
B. Chemicals used: Soda and alum are added for
flocculation and metal precipitation (as basic carbonates). The
metals treated or removed include nickel, chromium, copper, and
lead. The soda ash dosage was assumed to be 100 ppm on the waste
flow which is equivalent to 0.084 kg of soda asn/kkg of chlorine.
Alum was assumed
chlorine product as a
to be added in the
flocculating agent
amount of 0.14 kg/kkg of
C. Solid waste
of solid wastes
source of solid
cells and the
hydroxides. The
treatment plants
The brine mud constitutes the major source
from the process/treatment system. The other
wastes includes the asbestos froia the diaphragm
metals precipitated as basic carbonates and
total quantity of solids produced from the model
is 42.5 kg/kkg of chlorine.
11.4 TECHNOLOGY BASED POLLUTION ABATEMENT
11.4.1 Advanced Level Treatment Applications
Priority Pollutants to be Controlled
Existing regulations on diaphragm cell graphite anode
chlorine plants call for lead to be less than 0.0025 kg/kkg as a
30-day average. Other priority pollutants to be controlled
include asbestos, trace metals, and chlorinated organics.
174
-------
Removal Mechanisms Available
Asbestos particles can be trapped in a chemical floe,
settled and filtered. Possible alternate metal removal methods
include ion exchange and xanthate precipitation. Membrane
separation is not a viable alternative.
Selection of Appropriate Technology
Diaphragm Cell - BPT (Level !_)_ - Chemical coagulation with
alum is used to trap and settle suspended asbestos. Other wastes
containing toxic metals are then added, and soda ash is used to
precipitate the metals as metallic carbonates and hydroxides,
followed by settling and sludge separation. This two-stage Level
1 process provides gravity settling of asbestos-containing waste
and broadly controls heavy metals.
Diaphragm Cell - Level 2^ - Dual media filtration is added to
the BPT system. ~
Diaphragm Cell - Level _3 - A higher degree of metal removal
is provide provided By introducing sulfide precipitation ahead of
dual media filtration. This process involves only minor
equipment and chemical costs to achieve best available heavy
metal removal technology at reasonable cost. Ion exchange,
xanthate and membrane processes were not chosen for the same
reasons given under the mercury cell process.
Flow Diagrams
Flow diagrams for treatment of multiple waste streams from
the diaphgram cell process are shown by Figure 11-17 (Level 1),
Figure 11-18 (Level 2) , and Figure 11-19 (Level 3) .
Description of Each Treatment Level
Equipment Function - In the diaphragm cell waste water
treatment process conventional alum flocculation, settling, and
dual media filtration are used for asbestos separation.
Conventional sludge dewatering by filter press is used to dewater
the asbestos sludge before hauling, and the dual media filter
back wash is returned to the influent surge tank.
Level 2 treatment requires the addition of a reagent mixing
tank and chemical solution feeder to introduce ferrous sulfide
ahead of the Level 1 multi-media filter. All the equipment is
conventional and readily available.
175
-------
DKINE
LAGOON
LAGOON
TO PROCESS
I I SODA ASH
j: __
WASTE WATER
(METAL
CONTAMINATED)
ALUMpl
HOLDING TANK
ALUM
CELL ROOM
• WASTES '
|(ASBESTOS
CONTAMINATED)
MIXING
FILTER AID
,
(BATCH)
HOLDING TANK
SLUDGE
HOLDING
L-
SETTLING
TANK
IpH ADJUSTMENT
%
ftf]
r
i
FILTER
LANDFILL
r
•D-
*
-^- EFFLUENT
Includes pH monitoring, flov/ monHurinp
and sampler
Finure ll-17.Wastr water treatment Level 1 for chlorine - diaphragm cell subcalegory.
-------
BRINEi
MUD
LAGOON /"
RECYCLE
TO PROCESS
LAGOON
n
SODA ASK
WASTE WATER
(METAL
CONTAMINATED
ALUMfl
*-!
^J
^J
j HOLDING TANK
I
ALUM
CELL ROOM
WASTES
(ASBESTOS
I CONTAMINATED)
BACKWASH
FILTER AID
I
I
SETTLING
TANK
SUMP
FILTER
TO LANDFILL [
pH
DUAL
MEDIA
FILTER
*Include8 pH monitoring, flow monito
and sampler
Figure 11-18. Waste water treatment Level 2 for chlori
- diaphra^n cell eiix:ategory
-------
RECYCLE
TO PROCESS
LA GOO:-.
SODA ASH
r
WASTE WATER
(METAL
CONTAMINATED
00
BACKWASH
ALUM
1 HOLDING TANK
ALUM
CELL
' ROOM
I WASTES
'(ASBESTOS
I CO N TA M1N A TED)
(BATCH)
HOLDING
TANK
——~—
MIXING
FILTER AID
SLUDGE
HOLDING
TANK
I
SETTLING
TANK
FERROUS
SULFATE
ADJUSTMENT
SUMP
FILTER
SODIUM
BISULFIDE
ANDFILL I
DUAL
MEDIA
FILTER
EFFLUENT
Includes pH monitoring, flow monitoring
and sampler
Figure 11-19. Waste water treatment Level 3 for chlorine - diaphragm cell aubcategory.
-------
Chemicals and handling - In the diaphragm cell waste water
treatment process solutions of aluminum sulfate and sodium
carbonate are fed with conventional equipment. Inert filter aid
is used in the alum sludge filter process, and there ar no
unusual hazards in the Level 1 treatment. At Level 2 the
potential hazard in handling sodium sulfide is nullified by
reacting it with ferrous sulfate to form ferrous sulfide, which
then reacts with other residual heavy metals, leaving only excess
ferrous sulfide in solution, which oxidizes to ferric sulfide and
precipitates. At the point where sodium sulfide is reacted with
ferrous sulfate good ventilation is essential, but with a proper
excess of iron there is no subsequent hazard in handling the
ferrous sulfide at ph levels involved in the process.
11.4.2 Estimated Performance of BPT Systems
Diaphragm Cell Plants - Asbestos, used as a diaphragm
separating the cell anode and cathode, is the major pollutant
consistently found in process wastes from diaphragm cell plants.
It occurs primarily in wastes resulting from activities such as
cell room washdown and cathode repairing. Because of the
relatively recent concern about asbestos in waste waters, and
because of uncertainties in analytical procedures, asbestos has
not been regulated in plant discharges. The only control has
been with suspended solids limitations.
Asbestos control is practiced at several plants. Generally,
control consists of settling and/or filtering the waste water and
disposing of the solids in sealed containers or simply by
landfilling.
Lead, used as the electrical contact for graphite anodes, is
the major pollutant found in process waste waters from diaphragm
cell plants where graphite anodes are used. Conversion to metal
anodes has largely eliminated the source of lead in raw wastes.
Although not all diapnragm cell plants treat for lead removal,
treatment usually consists of sulfide or carbonate precipitation
and settling. Table 11-27 shows lead and suspended solids
effluent loadings at several diaphragm cell plants. Both
graphite and metal anode plants are shown.
BPT technology for waste water treatment and control at
diaphragm cell chlorine plants has been specified as asbestos
removal from wastes and containment of lead-bearing waste waters
followed by carbonate precipitation and settling before
di scharge.
The pollutants previously regulated at diaphragm cell
chlorine plants are suspended solids and lead. Priority
pollutants other than lead that were found at significant
concentrations in the screening and verification programs were
179
-------
1ABLE 11-27. EFFLUENT LOADINGS FRCM SELECTED CHLOR-ALKALI DIAPHRAGM CELL
PLANTS*
Plant
#589 **
# 738 **
#261 **
#014 **
#967
#207
Plant
#014 **
# 207
Lead
Average
0.002
0.001
0.0025
0.006
0.0085
0.021
Suspended
Average
2.81
0.30
Waste Load kg/kkg
Maximum
0.030
0.015
0.019
-
0.024
0.054
Solids Waste Load kg/kkg
Maximum
-
0.57
* See Reference 3
** Plants using metal anodes.
180
-------
identified as antimony, arsenic, chromium, copper, and nickel.
Carbonate precipitation is known to be effective for removal
of some trace metals. During the sampling programs, only one
diaphragm cell plant employing this treatment for lead was
visited. Table 11-28 presents the priority pollutant removal
efficiencies and effluent loads observed during the sampling of
that plant.
Base Level Performance Characteristics for BPT Pollutant Removal
Table 11-29 presents effluent quality achievable through
implementation of BPT or Level 1 treatment technologies for and
diaphragm cell chlorine plants.
Base Level Performance Characteristics for Priority Pollutant
Removal
Also presented in Table 11-29 is the estimated achievable
effluent qualities for priority pollutants with BPT technology.
Not included are estimates for the removal of chlorinated
organics or asbestos. Although only limited data are available,
it is not anticipated that chlorinated organics will be reduced
significantly with BPT treatment. Due to uncertainties in
analytical procedures, achievable asbestos loads using BPT
technology are being reserved at this time.
Pretreatment Applications
Several chlor-alkali plants presently discharge all or part
of their process waste water to POTWs. Pollutants present in
chlorine process wastes which require pretreatment include
mercury, lead, and chlorine. In addition, some control of pH and
suspended solids is required.
On the basis of the effluent quality achievable through the
application of BPT technology, as presented above, BPT technology
is also recommended for pretreatment.
11.4.3 Estimated Performance o_f Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
The advanced treatment performance estimates presented below
include estimates for chlorine discharges. Although this
parameter was not regulated in previous guidelines, and most
chlorine plants reuse or sell their chlorine-laden waste water,
the technology for chlorine removal has recently been established
181
-------
TABLE H-28. PRIORITY POLLUTANT REMOVAL AT LEAD TREATMENT FACILITY
PLANT*967
Pollutant o
£low =1.0 mVkkg
Pollutant Loads kg/kkg
Influent Effluent
Average Average
Removal
Antimony, Sb
Arsenic, As
Qiromium, Cr
Copper, Cu
Mercury, Hg
Nickel, Ni
Zinc, Zn
Lead, Pb
Thallium, Tl
0.00078
0.00032
0.00016
0.0049
0.000026
0.00069
0.0016
0.733
< 0.00004
0.00005
0.00037*
0.00005
0.00003
*
0.00005
< 0.00005
< 0.0001
0.029
0.00015*
93.6
—
68.7
99.4
—
>92.8
>93.8
96.0
__
Effluent is greater than influent.
182
-------
TABLE 11-29 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Chlorine - Diaphragm Cell
Level of Treatment: 1
Waste Water Flow: 12.8 m3/kkg
Quality Limit Emission Limit
Subcategory (1) (mg/1) (kg/kkg)
Pollutant Performance VFR
(mg/1) 30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants:
Total Suspended 2.0 37.5 75 0.48 0.96
Solids, TSS
Lead, Pb 2.0 0.6 1.2 0.008 0.016
Proposed Priority
Pollutants
Antimony, Sb
Arsenic , As
Chromium, Cr
Copper, Cu
Nickel, Ni
<0.
0.
0.
0.
0.
05(2)
25(2)
04(2)
03(2)
05(2)
2.
2.
2.
2.
2.
0
0
0
0
0
0.
0.
0.
0.
0.
8
5
1
5
5
1.
1.
0.
1.
1.
6
0
2
0
0
0.
0.
0.
0.
0.
01
006
0013
006
006
0.02
0.012
0.0026
0.012
0.012
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) Verification Sampling
183
-------
for this subcategory and therefore achievable limitations are
recommended .
Tables 11-30 and 11-31 present estimated achievable effluent
quality through implementation of advanced technologies.
New Source Applications
Examination of the waste water control and treatment
alternatives applicable to new chlor-alkali facilities has led to
the following conclusions:
All new sources should incorporate metal anodes rather than
graphite anodes. All new sources should provide for alternative
uses or provide for decomposition of chlorine-bearing wastes.
Diaphragm cell plants should provide treatment equivalent to
level 2 technology, providing better control of solids and lead.
Response to Remand Issues
Zero-discharge limitations origin-ally proposed for
chlor-alkali plants were remanded primarily because no plant was
shown to achieve zero discharge. The proposed alternative
advanced treatment levels provide for waste water discharge.
11.4.4 Cost Estimates
Discussion
On the basis of the model plant specifications and treatment
system design concepts presented earlier, the estimated control
costs for three production rates at diaphragm cell plants are
given in Tables 11-32 through 11-34. The costs shown at each
level of treatment correspond to the model plant BPT system
(Level 1) dnd one or more alternative BAT systems (Level 2, 3,
etc.) whicn may add to or modify the existing BPT system to meet
more stringent priority pollutant removal requirements. The BAT
systems also provide a higher effluent water quality with respect
to the conventional and nonconventional parameters.
Annual treatment cost as a function of production rate is
shown graphically in Figure 11-20. Similarly presented is the
relationship of unit cost (treatment cost per metric ton of
product) to production rate Figure 11-21. The estimated ranges
of total unit costs are shown and Table 11-35 presents a summary
of the unit cost distribution between amortization and operation
-------
TABLE 11-30 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Chlorine - Diaphragm Cell
Level of Treatment: 2
Waste Water Flow: 12.8 m3/kkg
Pollutant
Treatability
(mg/1)
Quality Limit
(1) (mg/1)
VFR
Emission Limit
(kg/kkg)
30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants;
Total Suspended 15
Solids, TSS
Lead , Pb 0.3
Total Residual
Chlorine, C12 0.2
Proposed Priority
2.0 15 30
0.19 0.38
2.0 0.3 0.6 0.004 0.008
2.0 0.2 0.4 0.0026 0.0052
Pollutants
Antimony, Sb
Arsenic , As
Chromium, Cr
Copper , Cu
Nickel, Ni
0.
0.
0.
0.
0.
4
1
05
1
1
2.
2.
2.
2.
2.
0
0
0
0
0
0.
0.
0.
0.
0.
4
1
05
1
1
0.
0.
0.
0.
0.
8
2
1
2
2
0.
0.
0.
0.
0.
005
0013
0006
0013
0013
0.01
0.0026
0.0013
0.0026
0.0026
1 - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
185
-------
TABLE 11-31 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Chlorine - Diaphragm Cell
Level of Treatment: 3
Waste Water Flow: 12.8 m3/kkg
Poll utant
ireataoii icy
(mg/1)
Quality Limit
(1) (mg/1)
30 day 24 hr
Av e r Ma x
Emission Limit
(kg/kkg)
30 day 24 hr
Av e r Max
BPT Pollutants;
Total Suspended 15
Solids, TSS
Lead, Pb 0.2
Total Residual
Chlorine, C12 0.2
Proposed Priority
2.0 15
30 0.19 0.38
2.0 0.2 0.4 0.0026 0.0-052
2.0 0.2 0.4 0.0026 0.0052
Pollutants
Antimony, Sb
Arsenic, As
Chromium, Cr
Copper, Cu
Nickel, Ni
0.
0.
0.
0.
0.
4
05
05
05
1
2.
2.
2.
2.
2.
0
0
0
0
0
0.
0.
0.
0.
0.
4
05
05
05
1
0.8
0.1
0.1
0.1
0.2
0.
0.
0.
0.
0.
005
0006
0006
0006
0013
0.
0.
0.
0.
0.
01
0013
0013
0013
0026
1 - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
186
-------
TABLE 11-32 MODEL PLANT TREATMENT COSTS
Subcategory CHLORINE Diaphragm cell
Production 19,100 metric tons per year
54 metric tons per day
Waste water flow 68 cubic meters per day.
A.
B.
C.
INVESTMENT COST
Equipment in place,
including piping,
fittings, electrical
Monitoring equipment
Engineering design
Inc identals , overhead ,
fees, contingencies...
TOTAL INVESTMENT COST
OPERATION AND
MAINTENANCE COST
Labor and supervision.
Chem ical s
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
TOTAL OPERATION AND
MAINTENANCE COST
AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
FIRST
$57,100
106,850
9,000
34,590
34,590
21,000
$263,130
$112,000
2,200
1,500
24,213
7,893
5,800
15,000
$168,606
$39,394
$208,000
Type of Regulation BAT
( 21,057 tons per year)
( 60 tons per day )
LEVEL OF TREATMENT*
SECOND THIRD
$1,800 $2,250
17,900 20,400
3,940 4,530
3,940- 4,530
$27,580
$14,000
300
2,758
827
7,500
$25,385
$4,487
$29,872
$31,710
$14,000
300
100
3,171
951
7,500
$26,022
$5,159
$31,181
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
187
-------
TABLE 11-33 MODEL PLANT TREATMENT COSTS
Subcategory CHLORINE Diaphragm
Production 95,500 metric
272 metric
Waste water flow 340 cubic m
A. INVESTMENT COST
Equipment in place,
including piping,
fittings, electrical
work and controls.....
Monitoring equipment
Engineering design
Incidentals , overhead ,
fees , contingenc ies . . .
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Enerqy
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
cell
tons per year
tons per day
eters per day.
FIRST
$148,100
219,700
9,000
75,360
75,360
63,000
$590,520
$112,000
4,900
7,500
52,752
17,715
29,000
15,000
$238,867
$85,827
$324,694
Type of Regulation
( 105,288 tons per yea:
( 300 tons per day
LEVEL OF TREATMENT*
SECOND
$2,900
27,000
5,980
5,980
$41,860
$14,000
600
4,186
1,255
7,500
$27,541
$6,810
$34,351
BAT
r)
)
THIRD
$3,350
29,500
9
6,571
6,571
$46,002
$14,000
600
500
4,600
1,380
7,500
$28,580
$7,484
$36,064
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
188
-------
TABLE U-34 MODEL PLANT TREATMENT COSTS
Subcategory CHLORINE Diaphragm cell
Production
Type of Regulation BAT
191,000 metric tons per year ( 210,577 tons per year)
545 metric tons per day ( 601 tons per day )
Waste water flow 680 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, contingencies...
Land
B.
TOTAL INVESTMENT COST
OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Maintenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
LEVEL OF TREATMENT*
FIRST SECOND THIRD
$271,900
295,500
9,000
115,280
•115,280
123,000
$929,960
$112,000
8,000
15,000
80,696
27,898
58,000
15,000
$316,594
$131,292
$447,886
$4,800
43,500
9,660
9,660
$67,620
$14,000
600
6,762
2,028
7,500
$30,890
$11,001
$41,891
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost,
$5,250
46,000
10,250
10,250
$71,750
$14,000
600
1,000
7,175
2,152
7,500
$32,427
$11,673
$44,100
189
-------
500
400
o
o
o
H
g' 300
U
D
2
2
200
100
!V
1 1
I/
/I
/
/ /
A
*
LEyELS #2
X
LEVEL;
r
A
#3
50 100 150 200
PRODUCTION, METRIC TONS/YEAR X 1000
Figure 11-20. Annual treatment cost vs. production for the Chlorine
Subcategory (Diaphragm Cell Process)
190
-------
12
10
U
w
ft
CO
50 100 150 200
PRODUCTION, METRIC TONS/YEAR X 1000
Figure 11-21. Annual unit treatment cost vs. production for the
Chlorine Subcategory (Diaphragm Cell Process)
191
-------
TABLE 11-35 MODEL PLANT TREATMENT COSTS
Subcategory CHLORINE Diaphragm cell
Type of Regulation BAT
Annual Treatment Costs ($/kkg)
LEVEL OF TREATMENT
PRODUCTION FLOW FIRST SECOND THIRD FOURTH
(kkg/yr) (m3/day) $ $ $ $
Annual Operation
and Maintenance
Annual
Amortization
Total Cost
19,100
95,500
191,000
19,100
95,500
191,000
19,100
95,500
191,000
68
340
680
68
340
680
68
340
680
8.83
2.50
1.66
2.06
0.90
0.69
10.89
3.40
2.34
1.33
0.29
0.16
0.23
0.07
0.06
1.56
0.36
0.22
1.36
0.30
0.17
0.27
0.08
0.06
1.63
0.38
0.23
Not
Applicable
192
-------
Summary
Although chlorine manufacture usually produces three waste
streams, only the brine mud and metal or asbestos contaminated
wastes are considered as contributing to waste flows and
treatment costs. Tail gas scrubber wastes, typically high in
sodium hypochlorite, are usually sold or returned to process, and
are therefore excluded from waste flows and waste treatment costs
for the model plants. however, for the range of annual
production in metric tons from 31,850 to 190,750, the annual cost
of decomposition of sodium hypochlorite varies from $1.26 to
$4.30 per metric ton of product (3).
The chlorine subcategory is a multi-product industry, since
caustic soda is a by-product of chlorine manufacture by either
process. In this report investment costs and annual costs are
expressed in terms of treatment cost per metric ton of chlorine
production, without considering the production or value of the
by-product caustic soda.
In this report brine mud is presumed to be left on-site in
accordance with current practice at many chlorine plants. For
neutralization, it is assumed that waste sulfuric acid is
available at the plant at no cost.
Diaphragm eel 1 base level BPT costs - Waste treatment cost
summary sheets for three chlorine production rates by the
diaphragm cell process are included as Tables 11-32, 11-33 and
11-34 respectively. Base level costs are shown as the First Level
of treatment. The unit costs of BPT treatment per metric ton of
chlorine production in Figure 11-21 are shown as the upper curve,
varying from $2.19 to $9.97 per metric ton.
Diaphragm cell advanced ley_e_l costs - Waste treatment cost
summary Tables 11-32, 11-33, 11-34 show incremental advanced
level costs in the column marked "second" and "third". The unit
costs per metric ton of chlorine production, at first, second,
and third level costs, are shown by the curve (Level 1, 2, and 3
Diaphragm Cell on Figure 11-21).
At the second level, the incremental cost varies from $2.37
to $11.36. There is insignificant difference in cost between
second and third levels. Hence, these two levels are represented
by the same curve on Figure 11-21.
193
-------
SECTION 12
HYDROFLUORIC ACID INDUSTRY
12.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
12.1.1 Industry Profile and Analytical Results
Hydrofluoric acid (Hydrogen fluoride-HF) is produced both as
anhydrous and aqueous products. It is used in the manufacture of
fluorocarbons which are used as refrigerating fluids, and
plastics, for pressurized packing and as dispersants in aerosol
sprays. It is used in the production of aluminum, in the
refining and enriching of uranium fuel, pickling of stainless
steel, in petroleum alkylation, and for the manufacture of
fluoride salts.
The industry data profile is given in Table 12-1, while the
existing regulations are given in Table 12-2.
The priority pollutants found at significant concentrations
in the raw waste during sampling at hydrofluoric acid Plant #705
were later verified at three other plants. The results were:
Maximum Concentration Observed
ug/1
Pollutant Screening Verification
(3 Plants)
Copper
Lead
Selenium
Zinc
Antimony
Arsenic
Cadmium
Chromium
Mercury
Nickel
Thallium
770
5190
25
8120
70
10
2
73
2
150
5.5
595
199
234
11313
2805
158
20
1180
43
2005
63
194
-------
TABLE 12-1
SUBCATEGORY PROFILE DATA .SUMMARY
SUBCATEGORY
HYDROFLUORIC ACID
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
363,000 kkg/year
261,800 kkg/year
14
177,000 kkg/year
68 percent
7,300 kkg/year
62,000 kkg/year
22,100 kkg/year
15,800 kkg/year
83 percent
7 years
58 years
0 cubic rasters/day
4,700 cubic meters/day
0 cubic meters/kkg
86 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Conmerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
195
-------
12-2 -
EXISTING REGULATIONS - EFFLUENT .LIMITATION GUIDELINES
SOT3CATEGORY Hydrofluoric Acid
SUBPAKT H (40 CFR 415.80, 3/12/74)
STANDARDS
Product
Process
Hydro-
fluoric
Acid
BFCTCA*
1 2
Max. Avg.
Para- kg/kkg k/kkg
meters (mg/1) (mg/1)
Fluoride (30)
(15)
BATEA*
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
No discharge
of pwwp 3
NSPS*
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
, No discharge
of pwwp
TSS
(50)
(25)
No discharge
of pwwp
No discharge
of pwwp
Sections 415.82, 415.83, and 415.85 were remanded and are presently
reserved (41 FR 51601, November 23, 1976) .
Max, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants.
196
-------
A summary of daily and unit product raw waste loads for all
plants sampled can be found in Table 12-3. Individual plant raw
waste loads per unit product found in sampling can be found in
Table 12-4.
Based on the total annual production of this subcategory and
the average waste load generated per unit product, the estimated
total priority pollutant raw waste loads generated each year for
this subcategory are as follows:
Pollutant Waste Load (kg/year)
Copper
Lead
Selenium
Zinc
Antimony
Arsenic
Cadmi urn
Chromium
Mercury
Nickel
Thallium
7300
2000
260
11000
7900
1500
71
6300
170
113000
550
12.1.2 Process Waste Sources and Waste Water Treatment Data
General Process Description
Raw mater ial and process - Hydrogen fluoride is the most
important manufactured compound of the fluorine family in volume
of production. Fluorspar (mainly CaF2) and sulfuric acid are the
raw materials used for its manufacture. The reaction is given as:
CaF2 + H2S04 + heat = CaS04 + 2HF (1)
Crude fluorspar, as mined, varies in CaF2 content from 50 to
90 percent. The ore is upgraded by flotation which results in 98
percent calcium fluoride being available for the production of
hydrofluoric acid.
The reaction kinetics and the yield of product depends on
the purity and fineness of the fluorspar. The concentration of
sulfuric acid, the temperature of the reaction, and the ratio of
sulfuric acid to fluorspar, are among the important variables.
The analysis of the fluorspar (average) is given as:
197
-------
TABLE 12-3 . SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
00
SUBCATEGORY
Pollutant
Priority
Antimony, Sb
Arsenic, As
Cadmium, Cd
Chromium, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel , Ni
Selenium, Se
Thallium, Tl
Zinc, Zn
Conventional
TSS
Fluorine, F
HYDROFLUORIC ACID
Minimum
0.015
0.012
0.0036
0.14
0.60
0.10
0.0027
0.14
0.016
0.0054
0.49
13587
497
kg/day
Average
1.63
0.46
0.011
1.73
1.42
1.74
0.056
3.90
0.066
0.084
21.1
132789
2971
Maximum
6.44
1.12
0.017
5.49
2.80
5.62
0.20
13.0
0.12
0.16
72.1
247438
7891
Loadings
Minimum
0.0003
0.0003
0.0001
0.0043
0.015
0.003
0.00008
0.0004
0.0005
0.00016
0.014
170
14.6
kg/kkg
Average
0.03
0.0056
0.00027
0.024
0.028
0.046
0.00065
0.051
0.001
0.0021
0.41
2711
45.4
No. of Plants
Maximum Averaged
0.12 4
0.012 3
0.00031 3
0.06 4
0.051 4
0.165 4
0.002 4
0.14 4
0.002 3
0.003 2
1.33 4
5702
86.9
-------
TABLE 12-4 . PRIORITY POLLUTANT RAW WASTE LOADS (in kg/kkg of Product)
SUBCATEGORY
POLLUTANT
Arsenic, As
Copper, Cu
Lead, Pb
Nickel, Ni
Selenium, Se
Zinc, Zn
Cadmium, Cd
Chromium, Cr
Mercury, Hg
Antimony, Sb
Thallium, Tl
HYDROFLUORIC ACID
#705
0.003
0.027
0.003
0.004
0.0005
0.269
0.0001
0.0043
0.00008
0.0016
PLANT
#705
0.018
0.0075
0.032
0.014
0.0004
0.018
0.0004
0.0004
# 251
0.012
0.015
0.0098
0.143
0.0013
0.031
0.06
0.002
0.0003
# 167
0.0045
0.051
0.025
0.0012
1.33
0.00031
0.012
0.00011
0.118
0.003
199
-------
CaF2 Minimum 97.5-98%
S102 Maximum 1.0%
S " 0.05%
H20 " 0.1%
CaCOS Principal remainder
Sulfuric acid with a concentration as low as 93 percent or
as high as 99 percent is generally used. Dilute sulfuric acid
enhances better mixing and liberation of fluoride but has two
disadvantages. The first disadvantage is that the dilute acid is
very corrosive and the second disadvantage is that the water
present in the acid evaporates and distills off with the hydrogen
fluoride gas, thus reducing product concentration. Concentrated
sulfuric acid (greater than 98 percent) offsets these
disadvantages but creates new problems. The vapor pressure of
concentrated sulfuric acid is sufficiently high to cause large
amounts of sulfuric acid to be carried away by the hydrofluoric
acid. Excess sulfuric acid, when used, will leave with the
gypsum as part of the residue.
The reaction between fluorspar and sulfuric acid is
endothermic. The reaction time varies and is usually between
20-60 minutes with the temperature of the reaction around 200-250
degrees C.
Hydrogen fluoride generators are, in the majority of cases,
externally fired rotary kilns with acid and fluorspar fed
continuously (through a screw conveyor) at the forward end and
calcium sulfate (gypsum) removed from the other end through an
air lock. The product also leaves this end, at the top, as a
gas. The theoretical amount of calcium sulfate produced is 3.4
kg/kg of HF produced, but because of the impurities in the
fluorspar the actual amount produced is higher and varies from
3.6 to 4.0 kg of crude calcium sulfate per kg of HF produced.
Silica is a highly objectionable contaminant, since each
pound consumes 2.0 pounds of fluorspar and 3.3 pounds of sulfuric
acid by the following reaction:
Si02 + 2CaF2 + 2H2S04 = SiF4 + 2CaS04 + 2H20 (2)
One manufacturer uses a patented process to supply internal
heat to the reactor. The heat is supplied by introducing sulfur
trioxide (S03) and water (as steam). The exothermic heat
liberated by the reaction of S03 and water is used for the heat
required for HF generation. Thus a part of the sulfuric acid is
supplied as S03.
200
-------
The hydrogen fluoride gas leaving the reactor is cooled in a
precooler to condense high boiling compounds. The condensables
are known as drip acid and largely consist of fluorosulfonic acid
(HS03F) and unreacted sulfuric acid. Nine plants out of a total
of eleven return the drip acid to the reactor, while the other
two send the drip acid to the waste treatment plant. The HF gas
from the precooler is further cooled and condensed in a
cooler/refrigeration unit. The uncondensed gas containing the HF
is scrubbed with sulfuric acid and refrigerated to recover the
product. The scrubbed acid liquor is returned to the kiln, and
residual vent gases are further scrubbed with water to remove HP
and other fluoride compounds before they are vented to the
atmosphere. The scrubber water is sent to the waste water
treatment plant. Figure 12-1 is a block flow diagram of the
manufacturing process.
The crude hydrofluoric acid is then distilled to remove the
residual impurities, and the condensate, which is anhydrous
hydrofluoric, is stored in tanks. If aqueous hydrofluoric is
desired, this is then diluted with water to form a 70 percent HF
solution as the final product.
Water Use and Waste Source Inventory
Water Use - Water is used in hydrofluoric acid production in
noncontact cooling, air pollution control, product dilution,
seals on pumps and kilns, and for equipment and area washdown.
Although noncontact cooling constitutes the major use of water,
water is also used, in a majority of cases, in the transport of
gypsum as a slurry to the waste water treatment facility. The
water for gypsum transport is provided by either recycling the
water from the treatment facility or by using once-through
cooling water. Table 12-5 summarizes the water usage found in
this study.
Waste Sources
A. Gypsum solids: Gypsum solids are generated as a
by-product. The amount produced is in the range of 3.6 - 4.0
kg/kg of HF produced. The gypsum also contains small amounts of
sulfuric acid, hydrofluoric acid and calcium fluoride. Minor
amounts of other impurities present in fluorspar are also removed
with the gypsum. In seven out of eleven plants producing
hydrofluoric acid, the gypsum is slurried with water and sent to
the waste water treatment facility. Three plants transport the
gypsum as a dry solid and dispose of it as a solid waste after
mixing with lime for neutralization. The disposal method of one
plant is not known.
B. Drip acid: This is formed in the first stage of the
cooling (i.e., in the precooler) of the gases emitted from the
201
-------
SOLFURIC
ACID
FLOORSPAR
SLURRY WATER
CALCIUM
SULFATE (GYPSUM)
SOLIDS
TO WASTE
NON-CONTACT
COOLING
WATER
NONCONTACT
COOLING OR
REFRIGERATION
SYSTEM
WATER'
EJECTOR
"I
WASTE WATER
TO
TREATMENT
WATER
WATER
SCRUBBER
WASTE WATER
TO STORAGE (OR
RECYCLED TO KILN)
LEGEND
COMMON PRACTICE
INTERMITTENT
PROCESS (OR PRO-
CESS AT ONLY
SOME PLANTS)
Figure 12-1. General process flow diagram for production of hydrofluoric acid.
202
-------
TABLE 12-5. WATER USAGE IN THE HYDROFLUORIC ACID SUBCATEGORY
Water Usage at Plant
fm /kkg of HF)
Source #987 #251 #753 #426 #120 #722 #167 #705
Non-contact NA 154 63.5 110 NA 13.6 116.5 30
Cooling
Gypsum Slurry 64 NA - NA 22.5 41.6 30
Transport
Maintenance, 2.4 NA 2.11 NA 0.1 12.2 5.0 16.9
Equipment and
Area Washdown
Air Pollution 14.4 7.9 4.23 - 0.586 14.45 19.31 11.25
Control
NA = Not Available.
203
-------
consisting
fluorosulfonic acid, and small
sulfuric acid, and water.
reaction between hydrofluoric
The quantity of drip acid
kiln. Drip acid mostly contains high boiling compounds
of complex fluorides, especially
amounts of hydrofluoric acid,
Fluorosulfonic acid is formed by
acid and strong sulfuric acid.
produced is relatively small. Nine out of eleven plants producing
HF recycle the drip acid back to the reactor. In most cases, it
is mixed with the sulfuric acid feed stream before it enters the
kiln where it is hydrolyzed to form sulfuric acid and
hydrofluoric acid. The critical factors for hydrolysis are
temperature and retention time and enough water is normally
present in the kiln for the reaction.
C. Noncontact cooling water: Noncontact cooling water is
used for precooling the product gases emitted from the kiln. The
possibility of product or other process compounds leaking into it
is very small, and this stream is relatively unpolluted. In some
plants the cooling water is used to transport the waste gypsum.
D. Scrubber waste water: Scrubber water is another waste
water source, and in plants which practice dry disposal of
gypsum, scrubber water constitutes the predominant and major
source of waste water. It contains fluoride, sulfate, and
acidity. The fluoride is present as hydrogen fluoride, silicon
tetrafluoride (SiF4), and hexafluosilicic acid (H2SiF6). Silica
present in the ore as an impurity reacts with HF forming silicon
tetrafluoride as shown in Equation 3.
Si02 + 4HF =
SiF4 + 2H20
(3)
In the scrubber, a part of the tetrafluoride is converted to
hexafluosilicic acid according to Equation 4.
SiF4 + 2HF(aq)
H2SiF6 (aq) (4)
The scrubber water consequently needs treatment for fluoride
before discharge.
E. Distillation wastes: The distillation waste generally
contains HF and water. In some cases the vent gases from the
distillation column are scrubbed before they are emitted to the
atmosphere, and the resulting scrubber water requires treatment.
The range of waste water quality of the different
generated from the production of HF is summarized in ^
The data are taken from the prior development
Questionnaire responses, and industry visits.
streams
Table 12-6.
documents, 308
204
-------
TABLE 12-6. WASTE FLOW FROM HYDROFLUORIC ACID MANUFACTURING PLANTS, m3/kkg OF HYDROFLUORIC ACID
Plants
Source of
Waste water #251 #987 #753 #426 #120 #722 #167 #705 #837
Gypsum Slurry 64.0 Dry NA Dry Dry (Total 41.6 (Total 6.5
disposal disposal disposal Recycle) Recycle)
Drip Acid 0.049 - - - - - - 0.018
Scrubber Waste water 14.4 8.3 2.3 - 0.624 (Total 40 11.25 1.12
Recycle)
o Other 0.53 0.53 8.4 NA 5.55 NA 5.2 22.52 NA
NA = Not Available
-------
Control and Treatment Practices
Plant #705 combines the hydrofluoric acid wastes, including
the gypsum slurry, with aluminum fluoride waste. The combined
waste water, after neutralization, is sent to settling lagoons
before discharge. This plant was visited in both the screening
and verification phases of the project and a fuller description
of waste treatment practice is given below.
Plant #837 combines the gypsum slurry and plant area
hosedown waste water with the equipment washings, leaks, and
spills etc. from the aluminum fluoride plant and neutralizes them
with lime. The solids are removed in settling ponds before
discharge. The waste water from scrubbers of both hydrofluoric
acid and aluminum fluoride plants is sent to an adjoining
facility for use.
Plant #251 also combines the hydrofluoric acid and aluminum
fluoride waste water. The suspended solids in the combined waste
water are removed in the gypsum ponds. The overflow from the
gypsum ponds is neutralized and the pH adjusted with the waste
water from other products which are manufactured on the site.
The plant is in the process of installing a new proprietary
treatment process to further reduce the fluoride in its waste
waters.
Two plants, #120 and #987, dispose of the kiln residue as a
solid waste after lime addition. The waste water in both cases
is treated with lime and the solids are separated; in one case in
a clarifier followed by a filtration, and in the other by
lagooning.
At Plant #167, the combined waste water (including the
gypsum) is neutralized with lime and then settled in lagoons
before discharge.
Plant #722 practices complete recycle. The gypsum slurry,
scrubber water, and other waste waters are combined and treated
with caustic soda for neutralization. The neutralized solution
is settled in lagoons and the overflow is treated with muriatic
acid before being recycled to the scrubbers arid to the kiln to
slurry the gypsum.
Plant #426 disposes of the gypsum solids from the kiln as a
solid waste after lime addition. The scrubber water is used to
make another product. The noncontact cooling water is
neutralized when required with caustic soda and settled before
discharge.
206
-------
Description of Plants Visited and Sampled
Screening - Plant #705 was visited and process waste water
samples were collected and analyzed for classical and priority
pollutants. The process used at this site is similar to the
conventional HF manufacturing process described earlier. The
drip acid is sent to the waste water treatment facility and the
gypsum produced from the reactor is slurried with water and also
sent to the treatment facility. The waste waters from the HF
production facility are combined with the aluminum fluoride plant
waste waters. The combined raw waste water is treated with lime
and sent to settling ponds before discharge. Figure 12-2 shows
the general process and the locations of the sampling points.
Table 12-7 gives the flow data and the total suspended solids
(TSS) and fluoride emissions.
Verification - Plant #705 was repeat sampled in the
verification phase and the same streams sampled. The variation
in the flow of the streams in the two sampling phases was
negligible. Table 12-8 gives the TSS and fluoride load summary of
the sampled streams.
One more HF plant (Plant 1251) was sampled in the
verification phase. The drip acid at this facility is also sent
to the waste treatment plant and the hydrofluoric acid waste
waters are combined with aluminum fluoride plant waste for
treatment. In addition to drip acid, the plant waste water
consists of scrubber water, gypsum slurry, and plant area hose
down. The treatment consists of gypsum ponds where the suspended
solids are removed. The overflow from the last gypsum pond is
neutralized and the pH adjusted with wastes from other product
lines. Figure 12-3 is a block diagram of the process showing the
sampling locations. Table 12-8 gives the summary of the waste
flow data and the concentration and loads of the important
classical pollutants.
Evaluation of Production and Waste Flow Data
When gypsum solids from the kiln are slurried with water for
treatment, the resulting stream constitutes the major source of
waste water. When kiln residue is disposed of as a solid waste,
scrubber waste water is the major source of waste. Table 12-9
gives the data for the direct and .indirect process contact waste
water going to treatment facilities. Noncontact cooling water has
not been included in the figures given in Table 12-9. Figure
12-4 is a graphical representation of production versus waste
water flow going to treatment facility for plants whose waste
water includes the gypsum slurry and for those practicing
disposal of kiln residue as a solid waste.
207
-------
VENT
FLUORSPAR
O
CO
t f
SCRUBBER
KILN
FRESH
WATER
DRIP ACID
LL
LIME
e
SURFfiCE DRAINS
COOLING TCWER
BLOWDOWN ,ETC.
&
Al(OH)
PH3DUCT
SETTLING PONDS
VENT
FRESHWATER "
e
Waste streams sanpled
Figure 12-2. General process flow diagram at Plant 5705 showing the sampling points.
Hydrofluoric Acid Manufacture
-------
TABLE 12-7 FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS OF PLANT #705 PRODUCLNG HYDROFLUORIC ACID
Stream Sampled Unit Flow Unit Fluoride Unit SS
No. Stream m3/kkg of HF kg/kkg of HF kg/kkg of HF
Description
1 Kiln Slurry 26.6 14.63 1360
2 Scrubber Waste 10 9.6 0.07
Water
3 Surface Drains 20 6.9 3.92
Cooling Tower
Slowdown
4 Treated Effluent 23.3 1.58 1.91
209
-------
TABLE 12-8. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE STREAMS
FOR PLANTS #705 AND #251 PRODUCING HYDROFLUORIC ACID
— —— — ~~~
Plant Stream Sampled Unit Flow
No. Stream m3/kkg of HF
Description
#705 1 Kiln Slurry 26.6
2 Scrubber Waste 10
Water
4 Surface Drains 20
Cooling Tower
Slowdown
5 Treated Effluent 23.3
#251 5 AHF Plant 1.2
Hosedown
6 S09 Scrubber 14.37
Waste
2 Gypsum Pond 82.3
Inlet
3 Gypsum Pond 82.3
Outlet
Unit Fluoride Unit SS
kg/kkg of HF kg/kkg of HF
3.8 4731
1.52 0.023
3.38 4.02
0.54 0.04
1.9 0.26
0.31 0.1
54 1533
26.5 0.8
210
-------
I\J
H
VENT
I WATER
15 (J^^l HOSK DOWN WATER
NIF
NEUTRALIZATION
SYSTIM
EFFLUENT
Waste streams sampled.
ALKALINE STREAMS
AND ACID FRCM OfHER PLANTS
Figure 12-3. General process flew diagram at Plant 1251 showing die sampling points.
Hydrofluoric Acid Manufacture
-------
TABLE 12-9. WASTE WATER INFLUENT DATA TO TREATMENT FACILITY IN THE
HYDROFLUORIC ACID SUBCATEGORY
Plant
#837
#705
#167
#722
#120
#426
#753
#987
#251
Kiln Residue
A
A
A
A
D
D
NA
D
A
Unit Waste Water Influent
to Treatment Facility
m /kkg of HF
120.6
58.2
166.4
49.4
9.08
0
11.1
13.61
82.4
A = Slurried with water.
D = Dry disposal.
NA = Not Available.
212
-------
15,000 t
12,500 H
10,000 -f
7,500 4-
r-H
fa
(-1
to
5,000 +
2,500
2,000
1,000 -I-
O
0
Dry Kiln Waste
Slurrying Kiln Waste
Figure 12-4.
75 100 150 200
HF Production, kkg/day
Production versus waste flow data for HF plants.
213
-------
Solid Waste Generation
The total solids generated from the process and the
treatment system consist of gypsum (CaS04) and the fluoride
precipitated as calcium fluoride. Table 12-10 gives the amount
of suspended solids going to the treatment facility (generated
from the process) and the quantity of total suspended solids
generated at the waste water treatment plant for the HF plants
visited in screening and verification. It can be seen from the
data that the gypsum waste is the major source of solids produced
and constitutes more than 95 percent of the total solids
produced. Table 12-11 gives the amount of gypsum solids produced
at different HF manufacturing facilities. It can be seen from
the table that the gypsum solids vary from 3.6 to 4.1 kg solids
per kg of product.
Process Modifications and Technology Transfer Options
1. Gypsum produced in the kiln can be disposed of as a
solid waste instead of being slurried with water and sent to the
waste water treatment facility. The solids in this case are
stored in piles on the land surface until alternative disposal
methods are found or the site abandoned. Although the dry
disposal method is labor intensive (involving transporation and
landfill operating cost), it has been found to be less expensive
due to the reduced initial capital requirement and operating
costs relative to the wet slurry method which requires a more
extensive system of pipes, pumps and on-site impoundments.
2. The use of soda ash in place of lime for neutralization
has some advantages. It eliminates or reduces the problem of
scale formation in the pipelines and scrubbers when the treated
waste water is recycled. It offers a faster reaction time and
better control of pH than lime. Even though the cost of soda ash
is higher than lime, soda ash has found to be a less expensive
alternative at some plants overall. After the use of soda ash,
the treated effluent water can be totally recycled, either to the
scrubber or to the kiln for transportation water for the gypsum.
Soda ash when added to raw waste water, increases the pH of the
stream. As the pH approaches 6, sodium replaces calcium present
in the gypsum waste. This frees enough calcium ion to
precipitate fluoride as calcium fluoride. Where the scrubber
water is the predominant source of waste water, the water has to
be first treated with enough lime to precipitate fluoride as
calcium fluoride. Soda ash can then be added to the supernatant
to precipitate calcium followed by neutralization with HC1 to
reduce scaling problems.
3. Two out of a total of 11 plants manufacturing
hydrofluoric acid send the drip acid to the waste water treatment
facility. The rest of the plants recycle it to the reactor.
214
-------
TABLE 12- 10. SUMMARY OF SOLID WASTE GENERATED FROM THE HF MANUFACTURING
PROCESSES AND TREATMENT FACILITIES AT PLANTS f 705 Aid #251
Plant Gypsum Solids Going To Total Solids Produced
Treatment Facility kg/kkg of HF
kg/kkg of HF
#705 3300 3377
#251 1533 1647
215
-------
'12-11. GYPSUM SOLIDS PRODUCTION IN THE HYDROFLUORIC ACID SUBCATEGORY
Unit Kiln Residue Produced Kiln Residue
Plant kg/kkg of HF Disposal/Treatment Method
#837 3.86 A
#705 NA A
#167 3.93 A
#722 NA A
#120 NA D
#426 4 D
#987 4.13 D
#251 4.0 A
A = Slurried with water and sent to wastewater treatment facility.
D = Dry disposal.
NA = Not Available.
216
-------
When discharged to the waste treatment system, the f 1 uorosulfonic
acid does not hydrolyze and leaves with the treated effluent as a
complex fluoride in soluble form. The total fluoride
concentration of the effluent will be higher for the plants
discharging drip acid compared to those which do not, after the
same neutralization treatment. The two plants discharging drip
acid to waste, looked into the feasibility of returning it to the
kiln, but because of the unique design of the kilns, they found
it to be economically unattractive. Bench scale studies have
shown that the drip acid can be hydrolyzed to free the HF.
HS03F + H20 + heat = H2S04 + HF (5)
The two plants not returning the drip acid to the kiln
should be able to hydrolyze the material in a separate unit
before commingling it with other wastes, thus avoiding the
treatability problem associated with complex fluorides.
Best Management Practices
1. Provision can be made to collect runoff from raw
material and product storage, process, and impoundment areas. It
should be treated with other process waste at the waste water
treatment facility. Leachate and permeate control needs to be
practiced on the solid waste stored in many plant premises as
gypsum piles. There is a risk that uncontrolled stockpiling may
contaminate the local ground water.
2. Ponds designed for solids removal must be deep enough to
have a minimum of disturbance from wind and rain. Baffles can be
used to reduce the frequency of wind-induced mixing, and episodes
of solids being resuspended and passing into the effluent be
reduced.
3. Performance evaluation and review of discharge quality
has been complicated by problems associated with chemical
analysis. Prior to July 1976, the method generally used for the
analysis of fluoride in industry was the specific ion electrode
or colorimetry. This method did not detect the soluble complex
fluoride species present in the waste water. The best method of
total fluoride detection (free as well as complex) is
distillation followed by analysis using the specific ion
electrode. Using the distillation method, the complex fluorides
are hydrolyzed and the resulting HF is carried over with the
distillate along with any free HF in the sample. Thus, the
method of total fluoride analysis used for effluent monitoring is
capable of measuring free fluoride and the fluoride present in
the form of complex ions which are not removed by lime treatment.
Monitoring data on effluent fluoride levels using the revised
217
-------
method are likely to be higher than the levels previously
reported under the same treatment conditions.
Model Plant and BPT Level Treatment System Specifications Process
The proposed BPT model treatment consists of:
A. Slurry transportation of kiln solids to an equalization basin,
B. Application of lime to precipitate CaF2, followed by lagoon
settling.
C. PH adjustment before final discharge.
D. Scrubber, cooling and distillation wastes enter the
equalization basin.
It is assumed that drip acid is recycled to the process
and does not appear directly in the waste stream.
reactor
For new or remodeled production facilities, the NSPS model
treatment system is based on hauling dry kiln residue directly to
a landfill. Miscellaneous liquid wastes in the NSPS model are
subjected to two stage lime-soda ash
neutralization/precipitation, followed by filtration and partial
recycling of effluent for use in scrubbers.
Waste water flow - The data in Table 12-9 for plants
sending the gypsum solids to the treatment facility indicate that
the unit flow varies from 49.3 m3/kkg of HF to 166.4 m3/kkg of
HP. For the model plants, a constant unit flow of 43 m3/kkg of
HF was assumed.
HF production - In the HF subcategory, production ranges
from a minimum of 7,300 kkg/year to a maximum of 62,000 kkg/year
with a mean of 22,100 kkg/year and a median of 15,800 kkg/year.
For waste water treatment cost estimates, three production levels
were selected as model plants. These are 19,000 kkg/year, 41,000
kkg/year, and 57,000 kkg/year.
Waste water pollutant load - The amount of kiln residue
varies from 3.6 to 4.1 kg/kg of HF produced. The waste water
going to treatment model plants is assumed to contain 3.8 kg of
solid kiln residue per kg of HF. Fluoride levels in waste water
have shown to vary as indicated below:
218
-------
12.2 TECHNOLOGY BASED POLLUTION ABATEMENT
12.2.1 Advanced Level Treatment Applications
Priority Pollutants to be Controlled
Priority pollutants in raw waste waters and slurries typical
of the HF industry include the heavy metals often found as
impurities in fluorspar. These metals are zinc, lead, nickel,
mercury, chromium, arsenic, copper, and selenium. Raw waste
waters from plants practicing dry disposal of kiln wastes may
include some of the same heavy metals in scrubber and area
washdown wastes, but in considerably smaller amounts, since the
spent ore is hauled as a solid waste and bypasses the waste water
treatment facilities. Although the fluoro-sulfonate complex is
found in HF wastes containing drip acid, organic compounds are
not anticipated in waste waters from this industry.
Removal Technologies Available
Although alkaline precipitation, sulfide precipitation, the
xanthate process, and ion exchange might be applied to clarified
solutions for control of metal ions, only alkaline precipitation
can be readily used for slurried kiln wastes from HF production.
Sulfide precipitation from cleared solutions will control zinc,
lead, nickel, and copper and to a lesser extent, antimony.
Selection of Appropriate Technology
BPT (Level 1) - Neutralization with lime, used widely in the
HF industry, is shown as the BPT treatment, principally to
control pH and the nonconventional pollutant - fluoride - which
is precipitated as calcium fluoride. Sufficient settled effluent
is recycled to transport kiln waste to the treatment facility as
a slurry, and the remainder is adjusted to a pH between 6 and 9
before discharge.
Level 2_ - Treatment is alkaline precipitation, using
additional lime and close control of pH in second-stage
neutralization, followed by lagoon settling. Sufficient lagoon
effluent is recycled to transport kiln waste to the treatment
facility as a slurry and the remainder is filtered to remove
finely divided metal hydroxides.
Level 3_ - It is assumed that 65 percent of the Level 2
effluent is recycled for transporting spent kiln waste to the
treatment facility. For the remaining 35 percent, pH adjustment
and sulfide precipitation are used ahead of the Level 2 dual
219
-------
media filter, to react witn residual lead, copper, nickel, zinc,
and antimony which may not nave reached their optimum pH levels
for alkaline precipitation.
Level 4_ - An alternative for Level 2, Level 4 employs soda
ash instead of lime for neutralization, depending on the spent
ore to contain enough calcium to precipitate calcium fluoride.
Use of soda ash permits increased effluent recycling without
scaling problems associated with calcium sulfate. To control
salinity and sodium alkalinity a final effluent blowdown of at
least 10 percent of the influent rate is maintained. The common
heavy metals will be precipitated as carbonates and hydroxides
with varying degrees of effectiveness at pH levels attainable
with soda ash. The effluent is filtered and adjusted to a pH
between 6 and 9 before discharge or process recycling.
New sources - The chosen NSPS treatment is dry handling and
off-site chemical landfill for the kiln waste and two-stage
alkaline precipitation with clarification and filtration for the
liquid process wastes. Heavy metal precipitation with soda ash
permits partial recycling for uses other than slurry transport.
Flow Diagrams
Flow sheets for the various levels of treatment are:
Level 1 (BPT) Figure 12-5
Level 2 (BAT) Figure 12-6
Level 3 (BAT) Figure 12-7
Level 4 (BAT) Figure 12-8
NSPS Figure 12-9
Equipment functions - Level 1, typical of existing treatment
facilities, utilizes very little equipment, but depends on lime
neutralization in settling lagoons, with final ph adjustment.
In Level 2, conventional dual media filtration is added to
the Level 1 system. In Level 3, standard reagent mixing and
solution feeding units are added to the Level 2 system. In Level
4/ which is an alternate for Level 2, the same type of chemical
feed equipment is used for soda ash as was used for lime in Level
2. Conventional lagoons and dual media filters are used in Level
220
-------
K)
NJ
H
LIME
RAW
WASTE WATER
EQUALIZATION
RECYCLE FOR SLURRY TRANSPORT
LAGOON
MIXING
LAGOON
pH ADJUSTMENT
T~^
EFFLUENT
*-
Includes flow monitoring, pH monitoring and sampler
Figure 12-5. vtaste water treatment Ijevel 1 for hydrofluoric acid subcategory.
-------
r
BACKWASH
LJME
NJ
K)
K)
RAW
I
I
-cb-
WASTE WATER
EQUALIZATION
•a-*1
^UXING
RECYCLE FOR
SLURRY TRANSPOR
LAGOOK
u
LAGOON
Q
ADJUSTMENT
FILTER
EFFLUENT
Includes flow monitoring, pH monitoring and sampler
Figure 12-6. waste water treatment Level 2 for hydrofluoric acid subcategory.
-------
to
K)
(^j RAW
x-— -^
\ '
LIME
1— Oh
1 ©
1
1
1
1
?
\ /
A 1 Z_
WAbTK WATKH * ' 1
EQUALIZATION 1
1 ^/->T
9
1
MIXII
1
M
r,
FEKI
SULI
__. BACKWASH
r
i .
1
1
1
1
1
V
/\
FILTEI
•EFFLUE
Includes flow monitoring, pH monitoring and sampler
Figure 12-7- Waste water treatment Level 3 for hydrofluoric acid subcategory.
-------
SODA ASH
RAW
K)
WASTE
WATER
•{*}-
EQUALIZATION
LAGOOM
"S—^
MIXING
LAGOON
RECYCLE: FOR |
SLURRY TRANSPORT RECYCLE TO
I I SCRUBBER
SUMP
, FILTER
X
1
V EFFLUENT
Includes flow monitoring, pH monitoring and sampler
Figure 12-8. Waste water treatment Level 4 for hydrofluoric acid subcategory.
-------
IpH ADJUSTMENT
LIME
Ln
LAGOON /
(SOLID WASTE)
RECYCLE TO
SCRUBBER
* EFFLUENT
Includes flow monitoring, pH monitoring and sampler.
Figure 12-9. Waste water treatment new source performance standard for hydrofluoric acid subcategory.
-------
4, but special attention to. selection of materials is required
because of the high salinity of recycled effluent. In the NSPS
model, dry kiln waste disposal is recommended with conventional
dry solids handling equipment. Lagoons, clarifiers, and filters
are used for scrubber, noncontact cooling, and other
miscellaneous liquid wastes. In this case, equipment for storing
and handling the dry Kiln waste is not considered to be waste
water treatment, and tne cost is not included in .the cost
estimates.
Chemical handling - Lime (as CaO) is the major chemical used
in Levels 1 and 2, along with minor amounts of hydrochloric acid
for final pH adjustment. With normal precautions, these
chemicals pose no special hazards. In Level 3, ferrous sulfide
is prepared on-site by mixing sodium bisulfide and ferrous
sulfate. Although sodium bisulfide can release toxic H2S at pH
levels below 7, the hazard can be mitigated by avoiding acid
conditions and by providing adequate ventilation. After mixing
its components, the ferrous sulfide solution is stable at the pH
levels employed in the process. In Level 4, only the common
chemicals sodium carbonate and hydrochloric acid are used,
without unusual safety hazards or special handling problems. In
the NSPS system only the common chemicals lime, soda ash and
hydrochloric acid are used, introducing no special problems of
safety or handling.
Separation and removal of sol ids - Solids are accumulated in
unlined settlinglagoons. ~Tn Level 4, calcium fluoride will
still precipitate in the lagoons but the total sludge quantities
will be less than in Levels 1, 2, and 3 where lime is used.
Solids from Level 4 treatment will be alkaline, very saline, and
difficult to consolidate. Dry solids from the NSPS model are not
subjected to treatment, except for nominal application of lime
before hauling in dry form to an approved chemical landfill.
Monitoring requirements - All levels of treatment except
Level 4 require monitoring of the effluent for TSS, pH, and
fluoride. Levels 2 and 3 should be monitored in addition for the
toxic heavy metals, zinc, lead, copper, chromium, and antimony.
At the metal concentrations being considered, these tests will
not be field tests made on routine operational samples. To
achieve desired accuracy, the sampling should be done by "new
condition equipment" and delivered promptly to a qualified
laboratory for anaysis by atomic absorption methods.
12.2.2 Estimated Performance o_f BPT Systems
Control and treatment practices for eleven plants producing
hydrofluoric acid are presented in Table 12-12. Also indicated
are other product-related waste water sources and pollutant loads
discharged.
226
-------
TABLE 12-12. SUM-1ARY CF WASTE WATER CCNTH3L AND TREATMENT TECHNOLOGY EMPLOYED AT ffifflRCFlLDEIC ACID HAN1S *
Plant Product-Related
Waste Water Sources
Control and Treatment Amount of
Technology Employed Treated
Waste Water
Recycled
Cooler Bottoms Effluent Volume Average RDllutaut
in mVmetric ton ^J5^ DisiaigaJ
(gal/short ton) of >«5/™tric ton)
Actual Production _ W««> lb)
Fluoride TSS
*426
Hydrofluoric acid
fluosilicic acids
production
Dry residue hauling 0
and duitping; neutrar
lization with caustic
of roncontact cooling
water and floor
drainage
Yes 465 (111,397) 1.2 ^
includes noncon-
tact cooling
water
664 Hydrofluoric acid
production
* 167 Hydrofluoric acid,
fluorocarbon,
Chlorine/sodium
hydroxide, and
hydrochloric acid
production
* 120 Hydrofluoric acid
production
967 Hydrofluoric acid,
fluorocarton, and
sulfuric acid
production
#928 Hydrofluoric acid
and aluminum
fluoride production
837 All hydrofluoric
acid generated as
used captively for
aluminum fluoride
production
753 Hydrofluoric acid
production
* 251 HP, AlFj, chlorine/
sodium hydroxide,
aluminum oxide, and
fluorocarton
production
f 705 Hydrofluoric acid
and aluminum
fluoride production
Residue slurry, neutra- 94%
lization with sodium
carbonate, settling,
recycle
Yes
Residue slurry, lime
treatment, settling,
recycle
Planned dry residue
handling, lime
treatment, clarification
47%
slurry, settling Present: 0
(Recycle and pH Planned: 70%
polishing facilities to 75%
under construction.)
Residue slurry, settling, 83%
recycle (Flocculation,
line treatment, and
clarification facilities
under construction.)
Residue slurry, lime 0
treatment, settling
Residue slurry, lime 65%
treatment, settling,
recycle, pH polishing
Yes
Yes
Yes
Yes
Yes
slurry, settling, 0
neutralization
722 Hydrofluoric and,
in recent past,
fluoboric,
acid production
Residue slurry, lime 30% to 35%
treatment, settling,
recycle, pH polishing
Residue slurry, lime 92% to 100%
treatment, settling,
recycle, pH polishing
Yes
5.78 (1,360)
Yes 103 (24,200)
ND
11.0 (2,650)
1 Kiln: Yes 22.2 x 10
3 Kilns: No (553 x ^
25.9 (6,204)
0.10 0.27
18 0.45
ND ND
125 (30,000) • Present: 24 16
Expected
additional1'8 2l1
facilities
9.44 (2,260) Present: 1 1.7
Expected
with . o.65 0.75
facilities
134 (32,200) 2.3 4.1
0.64 0.3S
46
530
3.2 O.M
0-10.3 (0-2,460) 0-0.81 0 to 0.54
See Reference 3
227
-------
It is clear from the table that a wide variation in effluent
quality exists within this subcategory. The factors believed to
cause these variations are the following:
Dry Residue Handling
The disposal of kiln waste by dry handling rather than
slurrying is practiced currently at two plants. This process
eliminates the major source of waste water generated at most
plants, greatly reducing the raw waste loads to be treated. The
only sources of waste water remaining are from air pollution
control and wasndown.
Effluent Recycle
Recycle of treated waste water for slurry transport of kiln
wastes is commonly practiced to varying degrees and clearly has a
major effect on pollutant loads discharged. Although four plants
do not practice recycle, it has been demonstrated sufficiently
that this practice is both technologically and economically
feasible.
Recycle of Condensables
Recycling of drip acid or condensable cooler bottoms reduces
the loading of fluoride in the treated effluent since the
fluoride species (fluorosulfonic acid) in this material is not
removed by conventional lime treatment. Only two plants do not
recycle drip acid .
Other Related Products
Most hydrofluoric acid plants also discharge wastes from
related products such as aluminum fluoride, f luo rocarbons,
hexafluorosilicic and tetrafluoroboric acids to treatment. These
other product wastes can account for higher raw waste loadings
and increase the potential for complex fluorides formation and
can also impact treatment efficiency by diluting the raw waste.
In addition, commingling of other product wastes will limit the
percentage of recycle of the total plane treated effluent.
In addition to the above factors, the design and operation
of the treatment facilities affect effluent quality. Solids
removal depends on retention time and surge capacity-
Precipitation of fluoride requires careful pH control and in
areas of heavy rainfall or winds, adequate freeboard or multiple
ponds are necessary to limit the discharge of high pollutant
loads due to unfavorable climatic conditions.
On the basis of the preceeding discussion, BPT technology
for the Hydrofluoric Acid Subcategory is:
228
-------
1. In-process recycle of condensables (drip acid).
2. Chemical treatment (with lime or soda ash) of the
waste waters for precipitation of fluoride.
3. Settling and retention of solids.
4. Recycle of at least 65 percent of treated waste water
for kiln waste slurry and transport.
5. pH adjustment of final effluent.
Data from four plants practicing effective effluent control
are summarized in Table 12-13.
An alternative to the above is dry handling of kiln residues
and lime treatment of scrubber and washdown wastes for
precipitation of fluorides.
Base Level Performance Characteristics for BPT Pollutant Removal
Table 12-14 presents effluent•quality achievable through the
implementation of BPT or Level 1 treatment technology for
hydrofluoric acid plants.
Base Level (BPT) Performance Characteristics for Priority
Pollutant Removal
Raw waste loadings of priority pollutants observed in
significant concentrations at hydrofluoric acid plants were
presented.
Two of the plants visited and sampled are practicing BPT
technology. Plant #705 was sampled for both screening and
verification and Plant #167 was sampled during verification.
Although Plant #705 does not recycle drip acid, the performance
for priority pollutant removal can be considered BPT.
Table 12-15 indicates the performance characteristics for
priority pollutant removal at Plants #705 and 1167. It is clear
that the effluent concentration in the discharge at Plant #705 is
well below the significant level and in many cases are below the
predicted treatability concentration with lime treatment. This
high performance is likely the result of the fact that many of
the metals found in the kiln slurry raw waste were in the ore
residue as solids and were simply settled out during treatment.
Table 12-14 also presents the achievable effluent quality
for priority pollutants using BPT technology.
229
-------
1ABLE 12-13.
SUMMARY OF EFFLUENT QUALITY ATTAINED AND VARIABILITY
OBSERVED AT FOUR REPRESENTATIVE HYDROFLUORIC ACID PLANTS
Treated Waste
Parameter
*
PH
Fluoride
TSS
Flow in
m3/kkg "
(gal/short ton)
*
PH
Fluoride
TSS
Flow in
3,
m /kkg
(gal/short ton)
*
PH
Fluoride
TSS
Flow in
m3/kkg
(gal/short ton)
Fluoride
TSS
Flow in
m3/kkg
/ -, , .
Average
6.8
0.10
0.29
5.6
(1,340)
ND
0.72
0.38
ND
9.0
0.81
0.54
10.2
(2,450)
ND
ND
ND
Daily
Standard
Deviation
1.1
0.09
0.16
3.8
(920)
ND
0.27
-
ND
2.8
0.52
0.37
5.5
(1,316)
ND
ND
ND
Load (kg/metric ton) (lb/1000 Ib)
Maximum
Plant
2.9 to 7.7
0.34
1.1
16
(3,760)
Plant
ND
2.0
-
ND
Plant
2.8 to 12.
2.6
1.2
24
(5,760)
Plant
ND
ND
ND
Average
#664**
6.8
0.10
0.27
5.6
(1,340)
#753**
ND
0.64
ND
11
(2,650)
#722**
2 ND
ND
ND
ND
#705**
0.49
0.84
26.8
(6,433)
Monthly
Standard
Deviation
Maxiinuni
0.7 5.0 to 7.5
0.04
0.18
2.1
(500)
ND
0.15
ND
ND
ND
ND
ND
ND
0.22
0.37
__
0.16
0.63
10.5
(2,500)
ND
0.76
ND
ND
ND
ND
ND
ND
0.8
1.53
139
(33,350)
(gal/short ton)
*Value in pH units.
ND = No data available.
** See Reference 3.
230
-------
TABLE 12-14 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Hydrofluoric Acid
Level of Treatment: 1
Waste Water Flow: 14.7 m3/kkg (65% Recycle)
Pollutant
Subcategory
Performance
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Av e r Ma x
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
BPT Pollutants:
Total Suspended 21
Solids, TSS
Fluoride, F
35
2.0 37.5
3.0 37.5
75 0.55 l.i
112 0.55 1.6
Proposed Priority
Pollutants
Arsenic , As
Chromium, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel, Ni
Selenium, Se
Zinc, Zn
0.
0.
0.
0.
0.
0.
0.
0.
06
05
(2)
06
3
(2)
01
(2)
09
(2)
01
3
2.
2.
2.
2.
2.
2.
2.
2.
0
0
0
0
0
0
0
0
0.
0.
0.
0.
0.
0.
0.
0.
5
1
5
5
1
5
2
5
1.
0.
1.
1.
0.
1.
0.
1.
0
2
0
0
2
0
4
0
0.
0.
0.
0.
0.
0.
0.
0.
0074
0015
0074
0074
0015
0074
0029
0074
0.015
0.003
0.015
0.015
0.003
0.015
0.0058
0.015
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Verification Sampling
231
-------
12-15.
PRIORITY POiLLUTANT REMOVE AT HYDROFLUORIC ACID PLANTS kg/kkg
Plant
Pollutant
Antimony, Sb
Arsenic, As
Cadmium, Cd
Chromium, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel, Ni
Selenium, Se
Thallium, Tl
Zinc, Zn
#705
Influent
0.00065
0.0025 <
0.0006
0.024
0.018
0.0031
0.00036
0.035 <
0.00016
0.015
Effluent
0.00012
0.0006
0.0001
0.0029
0.0012
0.0014
0.00003
0.0006
0.0003
0.00007
0.0033
#
Influent
0.0058
0.019
-
0.060
0 .015
0 .011
0.0034
0.14
0.008
-
0.031
167
Effluent
<0.026*
< 0.003
< 0.0003
0.032
0.010
0.0047
< 0.00015
0.077
*
0.011
0.0010
0.023
Flow (m3/kkg)2
62.1
127
*Effluent is greater than influent.
Values are for combined wastes from HF and AlF-
2
Values are for total raw waste from HF only
232
-------
Pretreatment Applications
No hydrofluoric acid manufacturing facility presently
discnarges to a POTW; consequently, no specific pretreatraent
technology has been proposed.
Response to Remand Issues
The original BPCTCA limitations for this subcategory
required zero pollutant disciiarge except in the event of excess
rainfall. Objections to the zero-discharge limitations concerned
the feasibility of using gypsum-saturated water for recycle to
air pollution control scrubbers.
The proposed BPT waste water control and treatment
technology allows for the discharge of process waste water after
appropriate treatment and recycle for kiln waste transport. This
technology is widely practiced in the industry and should pose no
technical problems. Implementation of BPT at all sites in the
industry will achieve the indicated pollutant discharge levels.
12.2.3 Estimated Perfo rmance of Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
Tables 12-16, 12-17 and 12-18 present estimated achievable
effluent quality through implementation of advanced technologies.
Pretreatment Applications
No hydrofluoric acid manufacturing facility presently
discharges to a POTW.
New Source Performance Application
Examination of raw waste loads indicates that the prime
source of pollutants at hydrofluoric acid plants is the kiln
waste. Currently, two plants handle their kiln waste as a solid
greatly reducing the total raw waste load and subsequent
effluent. Based on this and an examination of control and
treatment alternatives available to this industry, it has been
determined that new hydrofluoric acid facilities should achieve
effluent quality at least equivalent to BAT. The recommended
treatment technology for new sources as described in Section 8,
is dry handling of kiln wastes and chemical treatment, filtration
and recycle of other wastes. The use of soda ash
233
-------
TABLE 12-16 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Hydrofluoric Acid
Level of Treatment: 2
Waste Water Flow: 14.7 m3/kkg (65% Recycle)
Pollutant
Treatability
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Av e r Ma x
Emission Limit
(kg/kkg)
30 day
Aver
24 hr
Max
BPT Pollutants;
Total Suspended 15
Solids, TSS
Fluoride, F
Proposed Priority
25
2.0
3.0
15
25
30
75
0.22
0.37
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
0.44
1.1
Pollutants
Arsenic, As
Chromium, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel, Ni
Selenium, Se
Zinc, Zn
0.
0.
0.
0.
0.
0.
0.
0.
1
05
1
1
05
1
1
4
2.
2.
2.
2.
2.
2.
2.
2.
0
0
0
0
0
0
0
0
0.
0.
0.
0.
0.
0.
0.
0.
1
05
1
1
05
1
1
4
0.
0.
0.
0.
0.
0.
0.
0.
2
1
2
2
1
2
2
8
0.
0.
0.
0.
0.
0.
0.
0.
0015
0007
0015
0015
0007
0015
0015
0059
0.003
0.001
0.003
0.003
0-0015
0.003
0.003
0.012
234
-------
TABLE 12-17 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Hydrofluoric Acid
Level of Treatment: 3
Waste Water Flow: 14.7 m3/kkg (65% Recycle)
Pollutant
Treatability
(mg/1)
Quality Limit
(1) (mg/1)
VFR
Emission Limit
(kg/kkg)
30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants:
Total Suspended 15
Solids, TSS
Fluoride, F
Proposed Priority
25
2.0
2.0
15
25
30
75
0.22
0.37
0.44
1.1
Pollutants
Arsenic, As
Chromium, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel , Ni
Selenium, Se
Zinc, Zn
0.
0.
0.
0.
0.
0.
0.
0.
05
05
05
1
01
1
1
2
2.
2.
2.
2.
2.
2.
2.
2.
0
0
0
0
0
0
0
0
0.
0.
0.
0.
0.
0.
0.
0.
05
05
05
1
01
1
1
2
0.
0.
0.
0.
0.
0.
0.
0.
1
1
1
2
02
2
2
4
0.
0.
0.
0.
0.
0.
0.
0.
0007
0007
0007
0015
00015
0015
0015
003
0.0015
0.0015
0.0015
0.003
0.0003
0.003
0.003
0.006
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
235
-------
TABLE 12-18 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Hydrofluoric Acid
Level of Treatment: 4
Waste Water Flow: 4.2 m3/kkg (90% Recycle)
Pollutant
Treatability
(mg/1)
(1)
VFR
Quality Limit
(mg/1)
Emission Limit
(kg/kkg)
30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants:
Total Suspended 15
Solids, TSS
Fluoride, F
Proposed Priority
25
2.0
3.0
15
25
30
75
0.063
0.1
0.13
0.32
Pollutants
Arsenic, As
Chromium, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel, Ni
Selenium, Se
Zinc, Zn
0.
0.
0.
0.
0.
0.
0.
0.
1
05
1
1
05
1
1
4
2.
2.
2.
2.
2.
2.
2.
2.
0
0
0
0
0
0
0
0
0.
0.
0.
0.
0.
0.
0.
0.
1
05
1
1
05
1
1
4
0.
0.
0.
0.
0.
0.
0.
0.
2
1
2
2
1
2
2
8
0.
0.
0.
0.
0.
0.
0.
0.
0004
0002
0004
0004
0002
0004
0004
0017
0.0008
0.0004
0.0008
0. 0008
0.0004
0.0008
0.0008
0.0034
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
236
-------
precipitation of fluorides will allow recycle to air pollution
control scrubbers, the second major source of waste water.
Assuming 60 percent recycle, the achievable effluent quality
through implementation of this technology is indicated in Table
12-19.
Raw waste priority pollutant metals loadings from sources
other than kiln wastes were minimal and only occasionally
observed at potentially significant levels. it is assumed that
following chemical precipitation for fluoride removal, the
effluent loads discharged will be insignificant with regard to
these metals.
12.2.4 Cost Estimates
General Discussion
The costs shown at each level of treatment correspond to the
model plant BPT system (Level 1) and one or more alternative BAT
systems (Level 2, 3, and 4) which may add to or modify the
existing BPT system to meet more stringent priority pollutant
removal requirements. The BAT system also provides a higher
effluent water quality with respect to the conventional and
nonconventional parameters.
The estimated costs for three models having different
production levels are given in Tables 12-20, 12-21 and 12-22.
For these models, both the hydraulic and the pollution loads per
unit of production are held constant over the entire range of
production. Annual treatment cost as a function of production is
shown graphically in Figure 12-10. Similarly, treatment cost per
metric ton of product is given in Figure 12-11.
To indicate the effect on costs of an increased pollution
load per unit of production for a medium level of production
model plant, the pollution load was increased by 100 percent and
trie hydraulic load was held constant. The cost estimate
indicated that the annual unit cost per metric ton of product at
first and fourth (incremental) levels of treatment increased
approximately 40 percent and 90 percent respectively over the
original model unit cost. The increased cost is mostly due to
the additional cost of chemicals. Increase of pollutant loading
had no effect on the unit cost of treatment at other levels of
t reatment.
Similarly, for one model plant, the hydraulic load was
increased by 100 percent and the pollutant load was held
constant. The cost estimate indicated that the annual unit cost
per metric ton of product at the second and fourth levels of
i-
237
-------
TABLE 12-19 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Hydrofluoric Acid
Level of Treatment: NSPS
Waste Water Flow: 5.9 m3/kkg
Pollutant Treatability
(mg/1)
BPT Pollutants:
Total Suspended 15
Solids, TSS
Fluoride, F 25
Proposed Priority
Pollutants
Arsenic , As 0.1
Chromium, Cr 0.05
Copper, Cu 0.1
Lead, Pb 0.1
Mercury, Hg 0.05
Nickel, Ni 0.1
Selenium, Se 0.1
Zinc, Zn 0.4
(1
VFR
2.
3.
2.
2.
2.
2.
2.
2.
2.
2.
0
0
0
0
0
0
0
0
0
0
Quality Limit
) (mg/1)
30 day
Aver
15
25
0.1
0.05
0.1
0.1
0.05
0.1
0.1
0.4
24 hr
Max
30
75
0.
0.
0.
0.
0.
0.
0.
0.
2
1
2
2
1
2
2
8
Em
ission Limit
(kg/kkg)
30 day
Aver
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
088
22
0006
0003
0006
0006
0003
0006
0006
0024
24 hr
Max
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
18
66
0012
0006
0012
0012
0006
0012
0012
0048
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
238
-------
TABLE 12-20.MODEL PLANT TREATMENT COSTS
Subcategory HYDROFLUORIC ACID
Production
Type of Regulation BAT
19,100 metric tons per year ( 21,057 tons per year)
54 metric tons per day ( 60 tons per day )
Waste water flow 5220 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, contingencies...
Land
LEVEL OF TREATMENT*
FIRST SECOND THIRD FOURTH
$877,500 $24,500 $25,000 $24,500
92,000 89,500
23,400 22,800
23,400 22,800
386,
9,
254,
254,
1,020,
000
000
500
500
000
89,500
22,800
22,800
B.
TOTAL INVESTMENT CC6T
OPERATION AND
MAINTENANCE COST
$2,801,500 $159,600 $163,800 $159,600
Labor and supervision.
Enerqy
Chemicals
Maintenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$56,000
15,000
534,800
178,150
84,045
350,000
15,000
1,232,995
$289,850
$1,522,845
$14,000
1,500
15,960
4,788
7,500
$43,748
$25,966
$69,714
$14,000
1,800
3,400
16,380
4,914
7,500
$47,994
$26,650
$74,644
$14,000
1,500
367,700
15,960
4,788
7,500
$411,448
$25,966
$437,414
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
239
-------
TABLE 12-21. MODEL PLANT TREATMENT COSTS
Subcategory HYDROFLUORIC ACID
Production
Type of Regulation BAT
38,200 metric tons per year ( 42,115 tons per year)
109 metric tons per day ( 120 tons per day )
Waste water flow 10450 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, contingenc ies...
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
LEVEL OF TREATMENT*
FIRST SECOND THIRD FOURTH
$1,354,500 $35,000 $35,500 $35,000
533,500 131,000 137,500 131,000
9,000
379,400
379,400
1,944,000
$4,599,800 $232,400 $242,200 $232,400
33,200
33,200
34,600
34,600
33,200
33,200
Labor and supervision.
Energy.
Chemicals
Maintenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and repo rting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$56,000
21,500
1,069,600
265,580
137,994
700,000
15,000
2,265,674
$432,098
$2,697,772
$14,000
3,100
23,240
6,972
7,500
$54,812
$37,811
$92,623
$14,000
3,400
6,700
24,220
7,266
7,500
$63,086
$39,405
$102,491
$14,000
3,100
735,350
23,240
6,972
7,500
$790,162
$37,811
$827,973
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
240
-------
TABLE 12-22. MODEL PLANT TREATMENT COSTS
Type of Regulation BAT
Subcategory HYDROFLUORIC ACID
Production 57,300 metric tons per year ( 63,173 tons per year)
163 metric tons per day ( 180 tons per day )
Waste water flow 15700 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, contingencies...
Land
B.
LEVEL OF TREATMENT*
FIRST SECOND THIRD FOURTH
$1,755,500 $49,000 $50,000 $49,000
898,000
9,000
532,500
532,500
2,880,000
203,500
50,500
50,500
TOTAL INVESTMENT COST
OPERATION AND
MAINTENANCE COST
53,100 50,500
53,100 50,500
$6,607,500 $353,500 $371,700 $353,500
Labor and supervision.
Energy
Chemicals
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$56,000
30,600
1,604,400
372,750
198,225
1,050,000
15,000
3,326,975
$606,464
$3,933,439
$14,000
4,600
35,350
10,605
7,500
$72,055
$57,514
$129,569
$14,000
4,900
10,070
37,170
11,151
7 500
$84,791
$60,475
$145,266
$14,000
4,600
1,103,025
35,350
10,605
7,500
$1,175,080
$57,514
$1,232,594
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
241
-------
o
o
X
^
i
X
X
I ! !
ILEVIEIL #4
X
\z.
J£>
•H~T
m
i ! i
10 20 30 40 50
PRODUCTION, METRIC TONS/YEAR K 1000
60
Figure 12-10. Annual treatment cost vs. production for the Hydrofluoric
Acid Subcategory
242
-------
110
u
•to-
I
o
100
90
80
70
60
Figure 12-11.
10 20 30 40 50
PRODUCTION, METRIC TONS/YEAR X 1000
Annual unit treatment cost vs. production for the
Hydrofluoric Acid Subcategory
243
-------
treatment increased approximatley 70 percent and 10 percent
respectively over the original model unit cost. There was no
significant impact on the unit cost at other levels of treatment.
Table 12-23 presents a summary of the unit cost distribution
between amortization, operation and maintenance cost components
at various production and levels of treatment.
At the second, third and fourth levels of treatment, the
cost estimates are based on part of the waste water flow being
recirculated and the remaining flow being treated, thus the
subsequent treatment units are sized and estimated for lower
flows than if recycling were not practiced.
As explained under General Approach in Section 10, the costs
of recirculation have been excluded from the cost estimates
presented here.
For the model plant, the primary source of waste water is
the kiln waste, a slurry formed when water is used to transport
the solid residue (CaS04) after the reaction of fluorspar and
sulfuric acid. Other sources of process waste result from air
pollution control (scrubbers) and leaks, spills and washdown.
Model Plant Control Costs for Existing Sources
For the model plant control costs at the first level of
treatment, the disposal of the sludge is on-site and hence the
land requirements are fairly large. Chemicals, sludge hauling
and disposal costs have a significant impact on the total annual
costs. At the second and third levels of treatment however,
amortization, labor and supervision costs constitute a major
portion of the additional annual costs.
The fourth level of treatment is designed for recirculation
of the major portion of the treated effluent and therefore, soda
ash is used for neutralization in place of lime. Due to this
change, chemical cost has a significant impact on the additional
annual costs.
Model Plant Control Costs for New Sources
The basis of the selection of the model plant representing a
new source is described earlier in this section. The estimated
costs for three different models, having three different
production levels are given in Tables 12-24, 12-25 and 12-26.
Both the hydraulic and pollutant loads are directly proportional
to the production, i.e., the waste flow per unit of production
and the pollutant loading per unit of production are held
constant.
244
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TABLE 12-23 MODEL PLANT TREATMENT COSTS
Subcategory HYDROFLUORIC ACID
Type of Regulation BAT
Annual Treatment Costs ($/kkg)
PRODUCTION FLOW
(kkg/yr) (m3/day)
Annual Operation
and Maintenance
Annual
Amortization
Total Cost
19,100
38,200
57,300
19,100
38,200
57,300
19,100
38,200
57,300
5,220
10,450
15,700
5,220
10,450
15,700
5,220
10,450
15,700
FIRST
$
64.55
59.31
58.06
15.18
11.31
10.58
79.73
70.62
68.65
LEVEL OF
SECOND
$
2.29
1.43
1.26
1.36
0.99
1.00
3.65
2.42
2.26
TREATMENT
THIRD
$
2.51
1.65
1.48
1.40
1.03
1.06
3.91
2.68
2.54
FOURTH
$
21.54
20.68
20.51
1.36
0.99
1.00
22.90
21.67
21.51
245
-------
TABLE 12-24. MODEL PLANT TREATMENT COSTS
Subcategory HYDROFLUORIC ACID Type of Regulation NSPS
Production 19,100 metric tons per year ( 21,057 tons per year)
54 metric tons per day ( 60 tons per day )
Waste water flow 680 cubic meters per day.
A. INVESTMENT COST
LEVEL OF TREATMENT*
FIRST
Construction $64,000
Equipment in place,
including piping,
fittings, electrical
work and controls 327,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 80,000
Incidentals, overhead,
fees, contingencies... 80,000
Land 30,000
TOTAL INVESTMENT COST $590,000
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $56,000
Energy 6,100
Chemicals 44,000
Maintenance 56,000
Taxes and insurance... 17,700
Residual waste
disposal 742,000
Monitoring, analysis
and reporting 15,000
TOTAL OPERATION AND
MAINTENANCE COST $936,800
C. AMORTIZATION OF
INVESTMENT COST $91,112
TOTAL ANNUAL COST $1,027,912
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
246
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TABLE 12-25. MODEL PLANT TREATMENT COSTS
Subcategory HYDROFLUORIC ACID Type of Regulation NSPS
Production 38,200 metric tons per year ( 42,115 tons per year)
109 metric tons per day ( 120 tons per day )
Waste water flow 1370 cubic meters per day.
A. INVESTMENT COST
LEVEL OF TREATMENT*
FIRST
Construction $94,500
Equipment in place,
including piping,
fittings, electrical
work and controls 468,500
Monitoring equipment
in place 9,000
Engineering design
and inspection 114,400
Incidentals, overhead,
fees, contingencies... 114,400
Land 60,000
TOTAL INVESTMENT COST $860,800
B. OPERATION AND
MAINTENANCE CCST
Labor and supervision. $56,000
Energy 8,300
Chemicals 88,000
Maintenance 80,080
Taxes and insurance... 25,824
Residual waste
disposal 1,480,000
Monitoring, analysis
and reporting 15,000
TOTAL OPERATION AND
MAINTENANCE COST $1,753,204
C. AMORTIZATION OF
INVESTMENT COST $130,290
TOTAL ANNUAL COST $1,883,494
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
247
-------
TABLE 12-26. MODEL PLANT TREATMENT COSTS
Subcategory HYDROFLUORIC ACID Type of Regulation NSPS
Production 57,300 metric tons per year ( 63,173 tons per year)
163 metric tons per day ( 180 tons per day )
Waste water flow 2030 cubic meters per day.
A. INVESTMENT COST
LEVEL OF TREATMENT*
FIRST
Construction $120,700
Equipment in place,
including piping,
fittings, electrical
work and controls 601,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 146,140
Incidentals, overhead,
fees, contingencies... 146,140
Land 84,000
TOTAL INVESTMENT COST $1,106,980
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $56,000
Energy 12,250
Chemicals 132,000
Maintenance 102,298
Taxes and insurance... 33,209
Residual waste
disposal 2,226,000
Monitoring, analysis
and reporting 15,000
TOTAL OPERATION AND
MAINTENANCE COST $2,576,757
C. AMORTIZATION OF
INVESTMENT COST $166,438
TOTAL ANNUAL COST $2,743,195
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost,
248
-------
Annual treatment cost as a function of production is shown
graphically in figure 12-12. Treatment cost per metric ton of
product is given in Figure 12-13.
Table 12-27 presents a summary of the unit cost distribution
between amortization and operation and maintenance components.
For the model plant, the dry solids generated in the kiln,
are nauled to approved chemical dump sites, eliminating kiln
waste slurry. The waste water sources are air pollution control
(scrubbers), leak, spills and washdowns.
The cost of transporting dry kiln waste sludge to the
approved chemical dump site has been included in the cost
estimates. The cost of conveying the dry solids from the kiln
operation to the trucks (for transporting to the dump site) is
not included in the cost estimate. Such costs, which can vary
widely with site conditions, are considered to be process costs
and not part of treatment. A new plant would undoubtedly be
designed for direct loading of dry kiln waste.
Since the sludge disposal is not on site, the land cost has
negligible impact on total annual cost. However, the cost of
transporting the dry solids to the dump site constitutes about 75
percent of the annual costs.
249
-------
I i ' I
I !
I I
I !
o
o
o
^
o
o
o
X
co-
u
ZL_L
I I
I i
! 1
I ! !
\ i
I I
60
Figure
10 20 30 40 50
PRODUCTION, METRIC TONS/YEAR X 1000
12-12. Annual treatment cost vs. production for the
Hydrofluoric Acid Subcategory (NSPS)
250
-------
i I
60
U
50
I 1
i
u
IT
LJE
EIL '#
\ \
40
i ! I
30
I
10 20 30 40 50
PRODUCTION, METRIC TONS/YEAR X 1000
60
Figure 12-13. Annual unit treatment cost vs. production for
the Hydrofluoric Acid Subcategory (NSPS)
251
-------
TABLE 12-27 MODEL PLANT TREATMENT COSTS
Subcategory HYDROFLUORIC ACID
Type of Regulation NSPS
Annual Treatment Costs ($/kkq)
PRODUCTION FLOW FIRST
(kkg/yr) (m3/day) $
LEVEL OF TREATMENT
SECOND
$
THIRD
$
FOURTH
$
Annual Operation
and Maintenance
Annual
Amortization
Total Cost
19,100
38,200
57,300
680
1,370
2,030
49.05
45.90
44.97
19,100
38,200
57,300
19,100
38,200
57,300
680
1,370
2,030
680
1,370
2,030
4.77
3.41
2.90
53.82
49.31
47.87
252
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SECTION 13
HYDROGEN PEROXIDE INDUSTRY
13.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
13.1.1 Industry Profile and Analytical Results
The organic process is tne most commonly employed method in
the manufacture of Hydrogen Peroxide. Hydrogen Peroxide is used
as a bleaching agent in the textile, pulp and paper industries.
Other uses include chemical manufacture (e.g. plasticizers and
glycerine) , waste water treatment, and as a rocket propellant.
The industrial profile data is presented in Table 13-1 and
existing regulations in Table 13-2.
The priority pollutants found at significant concentrations
in the raw waste at screening plant #765 were:
Pollutant
Concentration (ug/1)
Pentachlorophenol
Phenol
Napthalene
4850
29
11
Dur ing
discovered
killer used
the basis
recommended
verification sampling of the same plant, it was
that the presence of organics were due to a weed
at the plant site, and were not process related. On
of these findings, this subcategory has been
for exclusion under Paragraph 8.
253
-------
TABLE 13-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
HYDROGEN PEROXIDE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
85,700 kkg/year
7
3
102,200 kkg/year
57,000 kkg/year
66 percent
5,560 kkg/year
28,730 kkg/year
15 years
27 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
254
-------
TABLE 13-2 - EXISTING REFLATIONS - EFFLUENT LJMTTATICN
SOBCATEGOKr Hydrogen Peroxide
SUBPAKT I (40CFR 415.90, 3/12/74)
STANDARDS
Product Para-
Process meters
Organic
Process
TOC
Electro-
lytic TSS
Process
BPCTCA
1 2
Max, Avg.
kg/kkg k/kkg
(mg/1) (mg/1)
0.8
(50.0)**
0.44
(27.5)
0.005
0.4
(25.0)
0.22
(13.8)
0.0025
BA1EA*
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
No discharge
of pwwp^
No discharge
of pwwp
No discharge
of pwwp
NSPS*
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/D
No discharge
of pwwp
No discharge
of pwwp
No discharge
of pwwp
Cyanide 0.0004 0.0002
(A)
No discharge
of pwwp
No discharge
of pwwp
Sections 415.93 and 415.95 were remanded and are presently reserved
(41 FR 51601, November 23, 1976) .
Max, = Maximum of any one day,
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants,
basis 16,000 1/kkg.
255
-------
SECTION 14
TITANIUM DIOXIDE INDUSTRY
14.1 ASSESSMENT OF THE WATER
PROCESS
POLLUTION POTENTIAL OF THE CHLORIDE
14.1.1 Industry Profile and Analytical Results
Chloride Process Industry
Titanium dioxide is manufactured by both a chloride process
and a sulfate process. Ti02 is a high volume chemical ranking
within the first fifty of all U. S. chemical production. Over
fifty percent of the titanium dioxide produced is used in paints,
varnishes and lacquers. About one third is used in the paper and
plastic industries. Other uses are found in ceramics, ink and
rubber manufacturing.
The industrial profile data
presented in Table 14-1, while the
Table 14-2.
for this subcategory is
existing regulations are in
The raw waste was not sampled during screeing at Titanium
Dioxide-Chloride Process Plant #172. No priority pollutants of
significance were found in the treated effluent.
Verification sampling was conducted at two plants. Priority
pollutants of significance found in the raw waste during
verification sampling were:
Maximum
Pollutant
Concentration
ug/1
Observed
Chromium
Lead
Nickel
Zinc
15200
5150
6320
3110
256
-------
TABLE 14-1
SUBCATEGORY PROFILE DATA SUMMARY
SUECATEGORY
TITANIUM DIOXIDE CHLORIDE PROCESS
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
610,000 kkg/year
389,000 kkg/year
8
5
184,600 kkg/year
142,000 kkg/year
30 percent
37 percent
16,900 kkg/year
45,200 kkg/year
28,400 kkg/year
25,600 kkg/year
77 percent
6 years
15 years
1,140 cubic meters/day
4,770 cubic meters/day
14 cubic meters/kkg
99 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
257
-------
TABLE 14-2 - EXISTING REGULATIONS - EFFLUENT LZMITATICN GUIDELINES
SUBCATEGOKY Titanium Dioxide
SUBPART
V (40CFR 415
.220, 3/12/74)
STANDARDS
Product
Process
Chloride
Process
Sulfate
Process
BPCTCA*
1 2
Max. Avg.
Para- kg/kkg k/kkg
meters (mg/1) (mg/1)
TSS 4'6
0.72
Iron
TSS 21'° **
ibb (100.0)
Iron -I -IN
2.3
0.36
10.5
(50.0)
0.84
/ A f\\
BATEA*
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
2.6 1.3
0.36 0.18
10.6 5.3
0.84 0.42
NSPS*
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
2.6 1.3
0.36 0.18
10.6 5.3
0.84 0.42
Sections 415.220, 415.222, 415.223, and 415.225 were remanded and are
presently reserved (41 FR 51601, November 23, 19761.
wax, = Maximum of any one day.
Avg. = Average of daily values for thirty consecutive days shall not exceed.
**flow basis 210,000 1/kkg.
258
-------
A summary of daily and unit product raw waste loads for all
plants sampled can be found in Table 14-3. Individual plant raw
waste loads per unit product found in sampling can be found in
Table 14-4.
Based on the total annual production of this subcategory and
the average waste load generated per unit product, the estimated
total priority pollutant raw waste loads generated each year for
this subcategory are as follows:
Pollutant Waste Load (kg/year)
Chromium 310,000
Lead 9300
Nickel 9700
Zinc 7400
14.1.2 Process Waste Sources and Waste Water Treatment Data
Chloride Process - General Description
The chloride process uses rutile or upgraded ilmenite ores
as raw material, since the process requires relatively pure
materials with a high titanium and a low iron content. For
ilmenite ores, a beneficiation process removes a part or all of
the iron from the low quality titanium ore. Several patented
processes exist for the beneficiation and two to three are in
current operation on a commercial scale. It has been claimed by
the industry tiiat the benef iciation process generates wastes, the
volume and chemical characteristics of which are different from
the chloride process waste alone, and different treatment
technology has to be used for pollutant removal before discharge
or disposal. One patented beneficiation process claims that the
only waste generated is solid waste which can be disposed of in
a landfill, but data on waste quality and quantity are not
available for this process. It is therefore assumed that the
wastes from the chloride process using beneficiation are
different from the process using pure high grade titanium ore.
Therefore, the subcategory, titanium dioxide, has been further
classified into three separate categories; sulfate process using
ilmenite ore, chloride process using rutile or upgraded titanium
ore; chloride process using ilmenite ore. This section is
restricted to the chloride process using rutile ore.
In the chloride process, the ore and coke are dried and then
reacted with chlorine to form titanium tetrachloride. The
titanium tetrachloride is then reacted with oxygen or air to form
titanium dioxide and chlorine, the latter being recycled to the
process. The chemical reaction taking place in the reactor is
259
-------
TABLE 14-3.
SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
SUBCATEGORY TITANIUM DIOXIDE - CHLORIDE PROCESS
Pollutant
Minimum
Priority
NO Chromium, Cr 1.76
CTi
Lead, Pb 0.0032
Nickel, Ni 0.14
Zinc, Zn 0.75
Conventional
TSS 442
Iron, Fe 7.57
Loadings
kg/day
Average Maximum Minimum
64.4 127 0.024
2.0 4.0 0.00004
2.04 3.93 0.002
1.47 2.19 0.01
4136 7828 6.06
768 1528 0.10
kg/kkg
Average
0.79
0.024
0.025
0.019
51.0
9.40
No. of Plants
Maximum Averaged
1.55 2
0.049 2
0.048 2
0.027 2
95.9
18.7
-------
TABLE 14-4. PRIORITY POLLUTANT RAW WASTE LOADS (in kg/kkg of Product)
SUBGATEGORY
POLLUTANT
TITANIUM DIOXIDE - CHLORIDE PROCESS
PLANT
#559
#120
Chromium, Cr
Lead, Pb
Nickel, Ni
Zinc, Zn
1.55
0.049
0.048
0.027
0.024
0.00004
0.002
0.010
261
-------
given as:
3C + 2T102 + 4C12 = 2 T1C14 + C02 + 2CO (1)
The reaction takes place at a temperature of 800 - 1000
degrees C and a fluidized bed reactor is generally used. The
product gases leaving the reactor consist of titanium
tetrachloride, unreacted chlorine, carbon dioxide, carbon
monoxide and minor amounts of heavy metal chlorides. The gases
are cooled initially to 250 degrees C to remove the impurities,
although in some cases purification is accomplished by washing
the gases with liquefied titanium tetrachloride. Iron chloride
and small amounts of vanadium, zirconium, and otner trace metal
chlorides are removed by centrifugation and the liquid recycled
to the absorber. Titanium tetrachloride is liquefied from the
gases after the first stage of cooling by further cooling to
ambient temperature. Copper, hydrogen sulfide and, in some cases,
proprietary organic complexing agents are added for purification
to the condensed solution. Copper acts as a catalyst to
decompose the phosgene formed in the TiC14 stream. Organic
complexing agents aid in separation of the TiCl4 from other
chlorides such as cupric chloride and silicon tetrachloride.
The residual uncondensed gases generally consist of
hydrochloric acid, chlorine, carbon monoxide, carbon dioxide,
nitrogen, and some titanium tetrachloride. They are treated to
remove acidic materials before being vented to the atmosphere.
The liquefied titanium tetrachloride contains impurities
such as aluminum chloride, silicon tetrachloride, etc., which are
removed by distillation. The distillate is the purified titanium
tetrachloride and the impurities remain as a residual which
becomes waste. The tail gases from the distillation column are
scrubbed to remove acidic materials. The titanium tetrachloride
product is then reacted with oxygen, as air, forming titanium
dioxide and chlorine:
TiC14 + 02 = Ti02 + 2C12 (2)
The rate of reaction is negligible below 600 degrees C but
increases rapidly above this temperature, and is generally
maintained between 1200 - 1400 degrees C for efficient reaction
and conversion. The needed heat is supplied by passing the
reactants through heat exchangers, by electric dischargers, or by
use of fluidized beds. After the oxidation reaction, the titanium
dioxide forms a solid and is separated from the gases either in
cyclones, baghouse filters, or Cottrell precipitators. The
residual chlorine is refrigerated and liquefied. The tail gases
262
-------
are scrubbed with caustic soda to remove chlorine before being
vented to the atmosphere. When air is _ used for oxidation,
chlorine recovery is achieved by absorption in trichlorethylene,
followed by distillation to remove chlorine. The titanium
dioxide is then sent to the finishing operation where it is
vacuum degassed and then treated with alkali, using a minimum
amount of water to remove traces of absorbed chlorine and
hydrochloric acid. The pigment is then milled, surface treated
for end-use application, dried, and packaged for sale. A
generalized process flow diagram, including the waste streams, is
shown in Figure 14-1.
Water Use and Waste Source Inventory
Water use - Water is used in noncontact cooling, for
scrubbing the tail gases from the purification and oxidation
reactor to remove contaminants, and in some cases, in the
finishing operation of the product. The total amount of water
usage varies from 45.3 to 383 m3/kkg of Ti02 produced, as shown
in Table 14-5. It can be seen in the same table that cooling
water constitutes the major use of water and varies from 10.7 to
280 m3/kkg of Ti02 produced.
Waste sources -
A. Wastes from cooling chlorinator gas: The waste consists
of solid particles of unreacted ore, coke, iron, and small
amounts of vanadium, zirconium, chromium, and other heavy metal
chlorides. They are either dissolved in water and sent to the
waste water treatment facility or disposed of in landfill as a
solid waste.
B. Chlorinator process tail gas scrubber waste: The
uncondensed gases, after the liquefaction of titanium
tetrachloride, are wet scrubbed to remove hydrogen chloride,
chlorine, phosgene, and titanium tetrachloride and chlorine in
the first stage. In the second stage, they are scrubbed with
caustic soda to remove chlorine as hypochlorite.
C. Distillation bottom wastes: These contain copper,
sulfide, and organic complexing agents added during purification
in addition to aluminum, silicon, and zirconium chlorides. These
are removed as waterborne wastes and reaction with water converts
silicon and anhydrous aluminum chlorides to their respective
oxides.
D. Oxidation tail gas scrubber wastes: The gases from' the
oxidation unit are cooled by refrigeration to liquefy and recover
chlorine. The uncondensed off-gases are scrubbed with water or
caustic soda to remove residual chlorine. When caustic soda is
used as the scrubbing solution, the resulting solution of sodium
263
-------
RUTILE ORE
ORINE
CHLORINATION
COKE
I
COOLING
1
SOLIDS
SEPARATION
SOLID WASTE
LIQUID
COOLING
AND
CONDENSATION
COPPER
LIQUID Ticl,
SCRUBBER
T '' f
PURIFICATION
AND
DISTILLATION
DISTILLATION
BOTTOM WASTE
TO
ATMOSPHERE
-*• SCRUBBER WASTE
LIME OR CAUSTIC
SCRUBBER
HYPOCHLORITE
DECOMPOSITION
TO
WASTE WATER
Tio2 PIGMENT
Figure 14-1.
General process diagram for production of
titanium dioxide (chloride process).
264
-------
TABLE 14-5. WATER USAGE IN TITANIUM DIOXIDE-CHLORIDE PROCESS
SUBCATEGORY
Water Use
Non-contact cooling
Direct process contact
Indirect process contact
Maintenance, equipment
cleaning and work area
washdown
Air pollution control
Water .usage at plants
m3/kkg of Ti02
Plant #102
182
10.5
NA
6.65
0.25
Non-contact ancillary uses 11.60
Sanitary & potable water
0.23
Plant #172
10.66
15.53
0.72
0.52
7.14
10.4
0.31
Plant #199
280
57
22.78
2.11
6.97
9.47
5.09
Total 211.23 45.28 383.42
NA = Not Available
265
-------
hypochlorite is either sold, decomposed, sent to the waste water
treatment facility, or discharged without treatment. The
scrubber waste stream also contains titanium dioxide
particulates.
E. Finishing operations waste: The liquid wastes from the
finishing operation contains titanium dioxide as a suspended
solid and dissolved sodium chloride formed by the neutralisation
of residual HCl with caustic soda.
Control and Treatment Practices
Two plants were visited and their waste waters sampled
during the screening and verification programs. Titanium dioxide
is manufactured at Plant #559 using the conventional chloride
process. The solids, hereinafter called pit solids, (mainly
unreacted ore, coke, iron, and trace metal chlorides, including
TiCl4), separated from the first stage cooling of the chlorinated
gases, are slurried with water and sent to the waste water
treatment facility. The waste water from the chloride process is
mixed with the other product waste water and treated in
combination. A flow diagram of the treatment facility, including
the sampling locations, is shown in Figure 14-2. The slurried
pit solids and the distillation column bottom residue are sent to
a large settling pond where they are mixed with the other process
waste water. The overflow from the settling pond is neutralized
with ground calcium carbonate in a reactor. The scrubber and
other waste water from the chloride process is mixed with other
product waste water and combined with the settling pond effluent.
The combined solutions are neutralized with lime in a second
reactor, and then sent to a settling pond before discharge.
Since the chloride process waste waters are mixed with other
product waste water prior to treatment, the sampling results
represent the total input mixture rather than the Ti02 process
raw wastes alone. Problems were encountered during the sampling
of the pit solids and the distillation bottoms. The pipes
carrying the wastes from the process discharged at the bottom of
the settling pond and it was not possible to take the samples
right at the outlet of the pipe. The combined sample of the two
streams was taken at the surface of the discharge. It is
probable that some solids settled before the stream reached the
surface. Table 14-6 gives the waste flows and pollutant loadings
for the streams sampled at Plant #559.
The second plant sampled, #172, makes titanium dioxide by
the conventional chloride process. The waste water from the
process, mainly the scrubber water, is collected in trenches and
sent to a central reactor basin. Other discharges, including a
part of the total rain runoff, are also collected in ditches and
sent to the reactor basin. In the reactor basin sodium hydroxide
is used for neutralization, and the resulting effluent is mixed
266
-------
OTHER PRODUCT
WASTE WATER
OTHER PRODUCT
WASTE WATER
to
CTl
SETTLING POND
ittl
SLURRIED —'
PIT SOLIDS
Sampling points
FINAL EFFIUENT
-DISTILLATION BOTTOM
WASTE WATER
SCIUBBER
WASTE WATER
OTHER PRODUCT
WASTE WATER
Figure 14-2. General flow diagram at Plant #559 showing the sampling points.
Titanium Dioxide (Chloride Process) Manufacture
-------
14-6. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT #559 PRODUCING TITANIUM DIOXIDE (CHLORIDE PROCESS)
Stream Stream
No. Description
Unit Flow
m /kkg
of TiO-
2
SS Load
kg/kkg
of TiO»
2
Iron Load
kg/kkg
of Ti00
2
Chromium Load
kg/kkg
of TiO~
2
Pit solids and 13.86
distillation
bottom waste
Settling pond 13.86
overflow
Ti02(Cl2 process) 90
scrubber and
other product
waste water
Final effluent 104(1)
(1)
(1)
95.7
0.22
28.2(1)
18.7
38.7
(1)
0.45
(1)
1.55
0.36
(1)
0.0096
(1)
0.0026
(1)
(2)
The pollutant load was calculated by apportioning the mass emitted
between the two waste streams on the basis of measured flows. This is
clearly a very approximate process and the results must be used with
caution.
The effluent value is higher than the influent because of the introduc-
tion of the other product waste water in the pond contributing to
higher load.
268
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with the remaining rain water runoff and sent to the first of two
retention basins arranged in series. The overflow from the
second retention is ph adjusted with sulfuric acid before
discharge. A simplified diagram of the treatment system,
including the sampling points, is shown in Figure 14-3. Table
14-7 gives the waste flow and pollutant loadings for the
streams sampled.
At Plant #199, all the process waste waters are combined,
including storm water and sanitary waste water. The combined
waste water is sent to a four-stage neutralization system, and
the effluent from each of the four stages of neutralization is
sent to a thickener. The thickener overflow is transferred to
the first of three of settling ponds, also in series. The
underflow from the thickener is heated to improve filtration
characteristics and filtered in four rotary drum filters. The
thickened solids from the filters are disposed of in a landfill
and the filtrate, wash water, and vacuum pump seal water is
recycled to the fourth stage of the neutralization train. The
overflow from the last settling pond is discharged.
The process waste water streams at Plant #102 are received
in two tanks, neutralized with lime, and then sent to a settling
basin. The settled solids are retained in the settling lagoons.
The plant has future plans for treating boiler blowdown, and
cooling tower blowdown, leaks and spills with the process waste
water.
At Plant #605, the unreacted ore and coke is disposed of as
a solid waste in the pit. The waste water from the process is
passed to two tanks for flow equalization, and the water is then
reacted with ground limestone slurried in water. The treated
solution is centr i f ugal ly treated to remove coarse solids which
are separated and landfilled. A flocculating agent is added to
the centrate and the solution is sent to a clarifier. The
clarifier overflow is degassed and the pH adjusted with caustic
soda (if required) before discharge.
Plant #172 mixes the process waste waters and the treatment
consists of lime neutralization and settling. The influent and
effluent from the treatment system was sampled and analyzed.
The distillation bottoms and the unreactd ore and coke are
slurried with water at Plant #559 and mixed with the other
process waste waters in a settling basin. The overflow from the
basin is neutralized with limestone and then mixed with the
scrubber waste water and waste waters from other products. The
combined waste water is neutralized with 1 irne and sent to a final
settling pond, the overflow from which is discharged. The
quantity of waste water from the titanium dioxide process, which
is treated at the treatment facility, is quite small compared to
the amounts from other product processes.
269
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PBOCESS WASTE WATER
RAIN RUNOFF
Sampling points
DISCHARGE
Figure 14-3. General flow diagram at plant #172 showing the sanpling points.
Titanium Dioxide (chloride Process) Manufacture
270
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TABLE 14-7. FLOW AND POIiUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT #172' PRODUCING TITANIUM DIOXIDE (CHLOPIDE
Parameter
Sampled Stream Description
Inlet to waste water
treatment pond
Waste water treatment
effluent
Stream no.
Flow, m /kkg
PH
TSS, kg/kkg of TiO-
Zinc, kg/kkg of TiO
Chromium, kg/kkg of
Iron, kg/kkg of TiO
Nickel, kg/kkg of
Ti°2
2
35.8
7.9
7.97
0.0096
0.0223
0.107
<0.0008
3
35.8
7.6
0.238
0.003
0.0006
0.011
< 0.00036
271
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Evaluation of Industry, Production and Waste Flow Data
In most cases, the caustic soda or water used to scrub the
tail gases is steam stripped before it is sent to the waste water
treatment facility. The unreacted ore and coke is either
disposed of as solid waste or slurried with water and sent to the
treatment facility. The process waste water is combined and
treated. The general -treatment practice of the industry is lime
neutralization and settling. The total solids generated at the
treatment facility include the unreacted ore and coke, hydroxides
of iron, titanium and other trace metals, and titanium dioxide.
The quantity of solids generated and the waste water flows going
to the treatment process is available for very few plants, but
the data available is given in Tables 14-8 and 14-9-
Process Modification and Technology Transfer Options
1. Research to develop economical techniques to recover the
vanadium and other metal values from the solid wastes generated
from the process waste treatment system would appear to be a
fruitful area of investment.
2. New plants can utilize refrigeration and high pressures
for chlorine liquefaction. This would reduce or eliminate the
chlorine residual problem in the tail gases. The capital cost to
modernize old plants is high, but these plants should have a
caustic soda or lime scrubber instead of a water scrubber to
remove residual chlorine from the tail gases. Caustic or lime
scrubbing removes a significant portion of the chlorine from the
tail gases as seen from the analagous data for the chlorine
subcategory given in Section 11.
3. When organic complexing agents are used for
purification, they are eventually removed with the distillation
bottoms. The distillation bottom wastes need to be segregated
from the other process waste waters because treatment systems
have not been designed for the removal of organic contaminants,
and it would be too expensive to modify them. Distillation
bottoms can be more efficiently disposed of by landfilling.
Best Management Practices
1. Provision should be made at all plants to collect storm
water runoff from the plant site and send it to the treatment
facility. Three out of a total of five existing plants are
presently treating storm water runoff.
2. Solid wastes generated at the process waste water
treatment facility may be contaminated with chromium, zirconium
and vanadium. Land disposal of these wastes should be in a
272
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TABLE 14-8. SOLID WASTE PRODUCED IN TITANIUM DIOXIDE-CHLORIDE PROCESS
Plant Amount of solids produced per unit of production
kg/kkg of Ti02
#102 563.4
#172 43.21
#199 552*
This value includes the waste from the titanium tetrachloride production
which is sold commercially. 62% of the total TiCl4 produced at this plant
is used for Ti02 production and the rest marketed for sale.
TABLE 14-9. WASTE WATER FLOW FOR TITANIUM DIOXIDE-CHLORIDE PROCESS
SUBCATEGORY
Plant Unit waste water flow going to treatment facility
m /kkg of Ti02
#102
#172
#559
28.87
35.8
95.66
273
-------
controlled landfill.
3. Leachate and permeate control is necessary if the solids
from the treatment facility are landfilled on-site.
Model Plants and BPT Level Treatment System Specifications
The BPT model treatment selected for the chloride process
Ti02 wastes consists of:
A. Equalization of all liquid wastes in first stage lagoons.
B. Neutralization with lime and settling in second stage
lagoons.
Chlorine-bearing tail gases are reacted with caustic soda or
caustic potash, and all such chlorinous liquids are considered to
be decomposed as part of the production process, with only the
chlorine free residual products going to the treatment facility.
The costs of thermal decomposition, which are relatively
insignificant, are discussed under the chlorine/caustic
subcategory of Section 11. Thermal decomposition consists of
cutting off the cooling water source after the exothermic
hypochlorite reaction, and addition of small amounts of nickel
and ferric chloride as catalysts. The solution is kept in a
closed, insulated tank foe four to five days for decomposition.
The rationale for selecting the model plants is discussed in
the following paragraphs.
Production - Five plants produce titanium dioxide from
rutile ore using the chloride process at a total production rate
of 142,000 metric tons per year. Production ranges from a
minimum of 16,900 kkg/year to a maximum of 45,200 kkg/year with a
mean of 28,400 kkg/year and a median of 25,600 kkg/year. For
waste water treatment cost estimates, three production levels
were selected as model plants. These are 16,900 kkg/yr, 25,500
kkg/yr, and 45,200 kkg/yr. This range of production includes all
United States plants.
Waste water flow - As discussed earlier and shown in Table
14-9, the unit acid waste water flow varies from 29 to 96 M3/kkg
of Ti02 produced. The main reason for variation in the waste
water flow is the difference in the chlorine recovery process
from the tail gases and the amount of scrubbing liquid used. The
waste water from the finishing operation is a significant portion
of tiie total waste water and depends on the type of titanium
dioxide end product desired. For model plants, a unit flow of 31
M3/kkg was used.
274
-------
Pollucant load - The primary pollutants occurring in the
waste "water a're suspended solids, acidity and chlorides of ferric
iron and other trace metals. The suspended solids (TSS) loading
as seen in Table 14-3 varies from 43 to 563 kg/kkg of Ti02, but
tiie low value represents a plant that hauls untreated ore and
coke, while the second value is based on unrepresentative
sampling. Consequently, a higher suspended solids loading of 800
kg/kkg of Ti02 is assumed for the model plants.
Treatment Chemicals - At the BPT treatment level, lime is
used for neutralization and precipitation. Based on the data
available for one plant, the rate of lime addition is assumed to
be 337 kg/kkg of Ti02.
Generation of Solids - Using a unit waste flow of 31 ra3/kg
(7,400 gallons per ton of product), the solids generated are
those present in the influent (5% by weight = 1.55 kkg/kkg) plus
the lime added for neutralization (.337 kg/kkg) or a total of
1.89 kkg solids per kkg of product. Solids are considered to be
accumulated in clay lined lagoons, with periodic mechanical
removal to on-site storage piles in clay lined areas draining to
the lagoons.
14.2 TECHNOLOGY BASED POLLUTION ABATEMENT
14.2.1 Advanced Level Treatment Applications
Control of Significant Observed Priority Pollutants
Pollutants to be controlled are the common heavy metals
found in the ore (i.e., chromium, lead, nickel, and zinc).
Although coke and certain proprietary organic complexing agents
are used in the chloride process, the production of chlorinated
organic priority pollutants is insignificant and does not warrant
specific treatment.
Not all of the priority pollutants listed above are found in
all ores of the same general type, nor are they found in all
plants utilizing the same process. However, the chosen
technologies at the various levels will be reasonably effective
in removing the heavy metal group.
Removal Technologies Available
Alkaline substances and sulfide compounds are used to
control tne heavy metals by precipitation as metallic hydroxides,
carbonates or sulfides. Ion exchange can remove metals from
clarified solutions, but is seluom specific enough to remove only
275
-------
the trace metals, and in solutions saturated with calcium and
other metals is not effective. Lime neutralization appears to
reduce the level of arsenic in actual plant waste waters, but the
reaction of sulfide with arsenic is too slow to be of practical
value in waste water treatment. Liuie treatment comoined with
ferric iron (added or already present in the waste stream) may be
the most effective means of controlling arsenic.
Selection of Technology to be Applied at Each Level
Chloride process - BPT (Level 1) The chloride process wastes
are equalized, neutralized with lime to a ph range of 6 to 9, and
settled in lagoons before discharge.
Level 2_ - Second-stage lime treatment is added to
precipitate metallic hydroxides, which are then filtered before
discharge.
Level 3_ - Ferrous sulfide treatment is added ahead of the
Level 2 filter to precipitate the heavy metals more effectively.
Alkaline precipitation was chosen at Level 2 because it
readily supplements existing lime neutralization by the simple
addition of filtration and increasing the Level 1 lime dosage.
Sulfide precipitation was chosen at Level 3 because it provides a
polishing treatment for most residual heavy raetals at a nominal
incremental cost beyond Level 2 treatment.
Figures 14-4, 14-5, and 14-6 show the model treatment
systems adopted for the chloride process.
Equipment functions - Chlorid_e Process - SPT treatment is
essentially lagooning with lime neutralization, using no special
equipment except a lime feeder and mixer.
In Level 2, second stage lime treatment is followed by
gravity clarification and multi-media filtration, with necessary
pH controls.
In Level 3, ferrous sulfide is added ahead of the Level 2
filter, to react with residual heavy metals more completely than
in the alkaline precipitation step at Level 2.
Chemicals and handling - Chloride Process - Lime and
hydrochloric acid are fed with conventional equipment at all
levels, and ferrous sulfide is prepared on-site by mixing ferrous
sulfate with sodium bisulfide. When normal dust control and good
ventilation are used, there should be no adverse effects from
Dandling these chemicals.
276
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LIME
RAW
WASTE WATER
LAGOON
LAGOON
LAGOON
MIXING
-\ LAGOON
EFFLUENT
Includes flow monitoring, pH monitoring and sampler.
Figure 14-4. Waste water treatment Level 1 for titanium dioxide - chloride process.
-------
RAW
WASTE WATEB
CO
LAGOON/—*!
LAGOON
BACKWASH
LIME
I
J
LAGOON
n
LIME
-\ LAGOON /—
FILTER PRESS
SUMP
TO LANDFILL
Includes flow monitoring, pH monitoring and sampler.
SUMP
CLARIFIER
DUAL
MEDIA
FILTER
pH ADJUSTMENT
* EFFLUENT
Figure 14-5. Waste water treatment Level 2 for titanium dioxide - chloride process.
-------
FERROUS
SULFATE
SODIUM
BISULFIDE
r
BACKWASH
LIME
p\ LAGOON /-*| Y i rA
KAW
WASTE WATER
U\ LAGOON
LAGOON
MIXING
LAGOON
FILTER PRESS
SUMP
TO LANDFILL
Includes flow monitoring, pH monitoring and sampler.
SUMP
CLARIFIER
* EFF-
MEDIA
FILTER
Figure 14- 6. Waste water treatment Level 3 for titanium dioxide - chloride process.
-------
Separation and removal of solids - Chloride Process - Inert
ore fractions and precipitated solids are accumulated in
clay-lined lagoons, which are alternately drained. Solids are
mechanically removed to self-draining 18 ft. High storage piles
on land provided at the site for a 10 year operating period. At
Levels 2 and 3, small amounts of heavy metal precipitates in
clarifier underflow are filter pressed and hauled to a secure
landfill.
Monitoring requirements - Chloride Process - Simple field
tests for oti and dissolved sulfide are used for internal process
monitoring. It should not be necessary to perform frequent tests
for the various heavy metals, except for compliance testing
required by agency permits. Samples are usually
flow-proportioned 24 hour composites, analyzed by atomic
absorption at a commercial laboratory.
14.2.2 Base Level Performance Characteristics for BPT Pollutant
Removal
Chloride Process
toaste waters from chloride process titanium dioxide
manufacture are similarly treated at all facilities. Treatment
typically consists of neutralization, final clarification and
ponding. Two plants dispose of unreacted ore and coke residue
(pit solids) as solid waste and treat all other wastes with
neutralization and settling.
BPT technology has been specified as solids settling
followed by neutralization of all wastes and clarification to
remove suspended solids.
Treated effluent quality data from Plant #172 and Plant #559
are presented in Table 14-10. Plant #172 disposes of its pit
solids as solid waste and hence does not have a raw waste load as
great as Plant #559.
Raw waste priority pollutants found in significant
concentrations during verification sampling were presented
earlier. The following were selected pollutants which might
require regulation: chromium, lead, nickel, and zinc.
Verification sampling results for Plant #559 and #172 are
presented in Table 14-10.
Base Level Performance Characteristics for BPT Pollutant Removal
Table 14-11 presents effluent quality achievable through
implementation of BPT or Level 1 treatment technology for
280
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TABLE 14-10. RAW WASTE AND TREATED EFFLUENT QUALITY AT TITANIUM DIOXIDE -
CHLORIDE PROCESS PLANTS
Verification Sampling:
i>Iant
Pollutant Raw Waste
kg/kkg
Total Suspended 6.06
Solids
Iron, Fe 0.104
Chromium, Cr 0.024
Lead, Pb 0.00004
Nickel, Ni 0.002
Zinc, Zn 0.010
Avg. Flow (m /kkg)
.#172
Treated Effluent
mg/1 kg/kkg
6.67 0.245
0.327 0.012
0.017 0.00062
<0.0023 <0. 000084
<0.010 <0. 00037
0.090 0.0033
35.9
Plant
Raw Waste
kg/kkg
95.9
18.7
1.55
0.049
0.048
0.027
13.9
#559*
Treated Effluent
mg/1
23.0
4.4
0.025
<0.0023
0.005
0.0617
Monitoring Data - Plant #172 Treated Effluent
Pollutant (Average)
mg/1
Total Suspended Solids, TSS 3.14
Chromium, Cr
Copper, Cu
Zinc, Zn
0.004
0.010
0.012
kg/day
8.34
0.013
0.027
0.028
kg/kkg
0.114
0.00018
0.00037
0.00038
Loads in effluent not included because it includes other process wastes.
281
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TABLE 14-11 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Titanium Dioxide - Chloride Process
Level of Treatment: 1
Waste Water Flow: 31 m3/kkg
Pollutant
BPT Pollutants:
Total Suspended
Solids, TSS
Iron, Fe
Proposed Priori
Pollutants
Chromium, Cr
Lead, Pb
Nickel, Ni
Zinc, Zn
Subcategory
Performance
(mg/1)
6. 2
(2)
0.3
ty
0.01
(2)
<0.004
(2)
<0.01
0. 02
Quality Limit
(1) (mg/1)
WtTR _ _
30 day 24 hr
Av e r Max
2.0 37.5 75
3.0 2.0 6.0
2.0 0.1 0.2
2.0 0.5 1.0
2.0 0.5 1.0
2.0 0.5 1.0
Emission Limit
(kg/kkg)
30 day
Aver
1.2 2
0.062 0
0.003 0
0.016 0
0.016 0
0.016 0
24 hr
Max
.4
.19
.006
.031
.031
.031
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Verfication Sampling
282
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titanium dioxide manufacture by the chloride process.
Base Level Performance Characteristics for Priority Pollutant
Removal
Also presented in Table 14-11 is the achievable effluent
quality through implementation of BPT technology for additional
priority pollutants found to be significant in screening and
verification of titanium dioxide plants.
Pretreatment Applications
Chloride Process
Presently no chloride process plant is discharging to a
POTW, however, BPT technology would be applicable to pretreatiaent
should such a discharge occur in the future.
Response to Remand Issues
Chlor ide Process
The effluent limitations for titanium dioxide by chloride
process were remanded as they applied to a process that combines
beneficiation of a low grade ilmenite ore and chlorination. The
original guidelines were only applicable to discharges resulting
from chloride process wastes, and did not include wastes from
benef iciation. Only two plants presently use the cnloride
ilmenite process. However, the benef ic iation step is integrated
with the manufacturing process in such a way at each plant that
waste loads cannot be separately measured.
As a result of the remand an additonal subcategory, titanium
dioxide by chlor ide-ilmenite process, has been assigned.
However, further studies are necessary before limitations can be
developed for this subcategory.
14.2.3 Estimated Performance p_f Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
Tables 14-12 and 14-13 present estimated achievable effluent
quality through implementation of advanced technologies.
283
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TABLE 14-12 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Titanium Dioxide - Chloride Process
Level of Treatment: 2
Waste Water Flow: 31 m3/kkg
Qual ity
Pollutant
Treatability
(mg/1)
(1)
VFR
30
(mg/
day
Aver
Limit
1)
24
Emission Limit
(kg/kkg)
hr
Max
30
day
Aver
24
hr
Max
BPT Pollutants;
Total Suspended
Solids, TSS
Iron, Fe
Proposed Priority
15
2.0
2.0
3.0
15
30
0.46
2.0
6.0 0.062
0.93
0. 19
Pollutants
Chromium, Cr
Lead, Pb
Nickel, Ni
Zinc, Zn
0.05 2.0 0.05 0.1 0.0016 0.0031
0.1 2.0 0.1 0.2 0.0031 0.0062
0.1 2.0 0.1 . 0.2 0.0031 0.0062
0.4 2.0 0.4 0.8 0.0012 0.0024
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
284
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TABLE 14-13 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Titanium Dioxide - Chloride Process
Level of Treatment: 3
Waste Water Flow: 31 m3/kkg
Pollutant
Treatability
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Av e r Max
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
BPT Pollutants:
Total Suspended 15
Solids, TSS
Iron, Fe 2.0
Proposed Priority
Poll utants
Chromium, Cr 0.05
Lead, Pb 0.1
Nickel, Ni 0.1
Zinc, Zn 0.2
2.0 15 30 0.46 0.93
3.0 2.0 6.0 0.062 0.19
2.0 0.05 0.1 0.0016 0.0031
2.0 0.1 0.2 0.0031 0.0062
2.0 0.1 0.2 0.0031 0.0062
2.0 0.2 0.4 0.0062 0.012
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
285
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New Source Applications
The control and treatment alternative considered as
applicable to new chloride process titanium dioxide facilities is
BPT technology. An in-plant control alternative is the disposal
of pit solids as solid wastes, as is presently practiced at one
plant. This will substantially reduce the raw waste pollutant
loads requiring treatment.
14.2.4 Cost Estimates - Chloride Process
Discussion
The costs shown at each level of treatment correspond to the
model plant BPT (Level 1) system and one or raore alternative BAT
systems (Level 2, 3) which may add or modify the existing BPT
system to meet more stringent priority pollutant removal
requirements. The BAT also furnishes a higher effluent quality
with respect to the conventional and nonconventional parameters.
For the chloride process, the cost estimates are developed
at 1st, 2nd and 3rd levels of treatment.
Summary
The estimated costs of three models having different
production levels are given in Tables 14-14, 14-15 and 14-16.
Annual treatment costs as a function of production are shown
•jraphically in Figure 14-7. Similarly, treatment costs pec-
metric ton of product are given in Figure 14-8.
Table 14-17 presents a summary of the unit cost distribution
between amortization and the operation and maintenance cost
components at various production and levels of treatment.
In model plant costs for existing sources at the base level
of treatment, amortization, chemicals and the residual waste
disposal costs have a significant inpact on the annual costs. At
treatment Levels 2 & 3, amortization, chemicals and labor
constitute a major portion of the additional annual costs.
286
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TABLE 14-14. MODEL PLANT TREATMENT COSTS
Subcategory TITANIIM DIOXIDE Chloride Type of Regulation BAT
Production 16,900 metric tons per year ( 18,632 tons per year)
48 metric tons per day ( 53 tons per day )
Waste water flow 1485 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $368,500 $49,000
Equipment in place,
including piping,
fittings, electrical
work and controls 209,000 389,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 117,300 87,600
Incidentals, overhead,
fees, contingencies— 117,300 87,600
Land 192,000 6,000
TOTAL INVESTMENT COST $1,013,100 $619,200
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $56,000 $84,000
Energy 3,700 4,300
Chemicals 140,000 34,100
Maintenance 82,110 61,320
Taxes and insurance... 30,393 18,576
Residual waste
disposal 108,000 9,000
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $435,203 $218,796
C. .AMORTIZATION OF
INVESTMENT COST $133,592 $99,767
TOTAL ANNUAL COST $568,795 $318,563
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
287
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TABLE 14-15. MODEL PLANT TREATMENT COSTS
Type of Regulation BAT
Subcategory TITANIIM DIOXIDE Chloride
Production 25,500 metric tons per year ( 28,113 tons per year)
72 metric tons per day ( 80 tons per day )
Waste water flow 2240 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $525,000 $50,800
Equipment in place,
including piping,
fittings, electrical
work and controls 228,000 450,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 152,400 100,160
Incidentals, overhead,
fees, contingencies... 152,400 100,160
Land 276,000 6,000
TOTAL INVESTMENT COST $1,342,800 $707,120
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $56,000 $84,000
Energy 4,000 5,500
Chemicals 211,000 51,000
Maintenance 106,680 70,112
Taxes and insurance... 40,284 21,213
Residual waste
disposal 164,000 11,000
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$596,964
$173,568
$770,532
$250,325
$114,072
$364,397
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
288
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TABLE 14-16. MODEL PLANT TREATMENT COSTS
Subcategory TITANIUM DIOXIDE Chloride Type of Regulation BAT
Production 45,200 metric tons per year ( 49,833 tons per year)
129 metric tons per day ( 142 tons per day )
Waste water flow 3980 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $815,500 $76,800
Equipment in place,
including piping,
fittings, electrical
work and controls 283,000 590,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 221,500 133,360
Incidentals, overhead,
fees, contingencies... 221,500 133,360
Land 504,000 6,000
TOTAL INVESTMENT COST $2,054,500 $939,520
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $56,000 $84,000
Energy 4,600 7,650
Chemicals 374,000 95,000
Maintenance 155,050 93,352
Taxes and insurance... 61,635 28,185
Residual waste
disposal 294,000 20,000
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $960,285 $335,687
C. AMORTIZATION OF
INVESTMENT COST $252,266 $151,883
TOTAL ANNUAL COST $1,212,551 $4 87,570
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
289
-------
2.0
O
o
o
\ f VFT . Jt? «r
iiL
I/
o
o
o
X_
t 1.5
X
8
u
#1
\ I
i.o
i i
0.5
10 20 30 40 50
PRODUCTION, METRIC TONS/YEAR X 1000
Figure 14-7. Annual treatment cost vs. production for the
Titanium Dioxide Subcategory, Chloride Process
290
-------
60
50
TT
* 40
'XJ
#2-8
30
LEVEL W.
20
10 20 30 40
PRODUCTION, METRIC TONS/YEAR X 1000
Figure 14-8. Annual unit treatment cost vs. production for the
Titanium Dioxide Subcategory, Chloride Process
291
-------
TABLE 14-17 MODEL PLANT TREATMENT COSTS
Subcategory TITANIUM DIOXIDE Chloride
Type of Regulation BAT
Annual Treatment Costs ($/kkg)
LEVEL OF TREATMENT
PRODUCTION FLOW
(kkg/yr) (m3/day)
FIRST
$
SECOND
$
THIRD
$
FOURTH
$
Annual Operation
and Maintenance
Annual
Amortization
Total Cost
16,900
25,500
45,200
16,900
25,500
45,200
16,900
25,500
45,200
1,485
2,240
3,980
1,485
2,240
3,980
1,485
2,240
3,980
25.75
23.41
21.25
7.90
6.81
5.58
33.66
30.22
26.83
12.95
9.82
7.43
5.90
4.47
3.36
18.85
14.29
10.79
13.27
10.09
7.65
6.
4.
3.
07
60
47
19.33
14.68
11.12
Not
Applicable
292
-------
14.3 ASSESSMENT OF THE WATER POLLUTION POTENTIAL OF THE SULFATE
PROCESS
14.3.1 Industry Pj_o_fjL_l_e and Analytical Results
Sulfate Process Industry
The industrial profile for this subcategory is given in
Table 14-18 and existing regulations in Table 14-2.
Tne priority pollutants found at significant levels in the
raw waste during sampling at Titanium Dioxide - Sulfate Process
plants were as follows:
Pollutant
Maximum Concentration Observed (ug/1)
Ver ification
Screening (2 Plants)
Cadmium
Chromi urn
Copper
Lead
Nickel
Z inc
Phenol
Silver
Antimony
Arsenic
Thallium
338
123,600
1475
3729
6370
3840
20
64
20
11
19
11.7
30,600
1,000
5,193
1,295
16,610
No Sample Taken
<15
1,400
340
41
A summary of daily and unit product raw waste loads for all
plants sampled can be found in Table 14-19. Individual plant raw
waste loads per unit product found in sampling can be found in
Table 14-20.
Based on the total annual production of this subcategory and
the average waste load generated per unit product, the estimated
total priority pollutant raw waste loads generated each year for
this subcategory are as follows:
293
-------
TAB. -
SUBCATEGORY PROFILE DATA .SUMMARY
SUH
TITANIUM DIOXIDE SULFATE PROCESS
Totitegory capacity rate
Totitegory production rate
Numllants in this subcategory
308. file for
tal capacity of
ital production of
nting capacity
nting production
reduction range:
Minimum
Maximum
production
production
capacity utilization
ge range:
Minimum
Maximum
ter flow range:
Minimum
Maximum
per unit product:
Minimum
Maximum
401,000 kkg/year
259,000 kkg/year
5
5
320,000 kkg/year
246,000 kkg/year
80 percent
95 percent
31,000 kkg/year
74,500 kkg/year
49,000 kkg/year
43,000 kkg/year
76 percent
23 years
54 years
35,000 cubic meters/day
125,000 cubic meters/day
300 cubic meters/kkg
780 cubic meters/kkg
Sou;data are Stanford Research Institute, Directory of Chemical
Prau.S.A., 1977, U.S. Department of Commerce, Current Industrial
Repecenber 1977; Energy and Environmental Analysis, Inc.; Draft
Repreliminary Economic Assessment of Effluent Limitations in the
Inochemical Industry."
293A
-------
TABLE 14-19 . SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
SUBCATEGORY TITANIUM DIOXIDE - SULFATE PROCESS
Pollutant
Minimum
Priority
Antimony, Sb 7.66
Arsenic, As
Cadmium, Cd 0.091
Chromium, Cr 132
Copper, Cu 8.30
Lead, Pb 3.28
Nickel, Ni 8.30
Thallium, Tl
Zinc, Zn 53.4
Organic s
Phenol 0 . 20
Conventional
TSS
Iiron Fe
Loadings
kg/day
Average Maximum Minimum
18.0 28.3 0.08
1.31
2.40 6.85 0.0009
200 327 1.36
11.6 15.1 0.094
8.56 12.4 0.037
11.5 14.7 0.086
0.76
55.3 57.1 0.55
2O478
58452
kg/kkg
Average
0.21
0.014
0.027
2.11
0.12
0.089
0.12
0.0078
0.57
0.002
211
6O2
No. of Plants
Maximum Averaged
0.32 2
1
0.078 3
3.37 3
0.16 3
0.13 3
0.15 2
1
0.59 2
-------
TABLE). PRIORITY POLLUTANT RAW WASTE LOADS CLn kg/kkg of Product)
SUBCA
PQLLU
Cadmi
Chromr
Coppe
Arsen.
Lead,
Nicke.
Zinc,
Antimo
Pheno.
Thalli
TITANIUM DIOXIDE
#559
0.0009
3.37
0.118
0.0135
0.103
0.151
0.55
0.08
0.0078
- SULFATE PROCESS
PLANT
#559
0.003
1.36
0.155
0.128
0.086
0.589
0.002
#555
0.078
1.61
0.094
0.037
0.322
295
-------
Pollutant
Waste Load (kg/year]
Cadrai urn
Chroraiuw
Copper
Lead
Nickel
Zinc
Antimony
7000
548000
31000
23000
31000
150000
54000
14.3.2 Process Waste Sources and Waste Treatment Data
Sulfate Process - General Description
Among the various titanium ores, ilmenite is available in
abundance. Ilmenite is a low-grade titanium ore with a Ti02
content varying from 45 to 60 percent. Ilmenite ore and slag from
iron production generally comprise the raw materials used for the
preparation of titanium dioxide by the sulfate process. Large
amounts of water and sulfuric acid are used in this process, and
the majority of the plants are co-located with sulfuric acid
plants. Table 14-21 gives the analysis of various ilmenite ores.
The preparation of Ti02 by the sulfate process utilizes three
important steps:
(1) Digestion: FeO.Ti02 + 2H2 S04 = feS04 + TiO.S04 + 2H20
(2) Precipitation: TiO.S04 + 21-120 = Ti02.H20 + H2S04
(3) Calcination: Ti02.H20 = Ti02 + ti20
The ore is dried, ground and then reacted with sulfuric
acid. The reaction takes place at 160 degrees C and the reacted
mixture consists of titanyl, ferrous, and ferric sulfates. The
total iron in the reacted product is kept in the ferrous state by
the addition of scrap iron. After the reduction, the product is
dissolved in water and clarified with the aid of flocculating
agents to remove insoluble impurities such as silicon, zirconium
unreacted ore. The iron is removed from the clear solution
cooling the solution to 10 degrees C when FeS04.7H20
ferrous sulfate crystals, commercial copperas,
separated from the solution by filtration or
The concentrated titanyl sulfate solution is
and heated to form titanium dioxide hydrate
the
and
by
crystallizes. The
are mechanically
centrifugation.
diluted with water
which precipitates out. The suspension is filtered and
filtrate, wnich is known as strong acid, is separated and either
discharged or recycled. The Ti02.H20 filter residue is slurried
with water and conditioning agents are added to control particle
296
-------
TABLE 14-21 . ANALYSIS OF ILMENITE ORES
-0
Chemical
Constituent
Ti02
FeO
Fe2°3
Si°2
A1203
P2°5
Zr02
MgO
Mrt)
CaO
V2°5
Cr 0
UNITED STATES
Virginia
Piney
River Roseland New York
44.3
35.9
13.8
2.0
1.21
1.01
0.55
0.07
0.52
0.15
0.16
0.27
51.4
37.9
1.6
4.6
0.55
0.17
2.35
0.70
0.59
0.07
44.4
36.7
4.4
3.2
0.19
0.07
0.006
0.80
0.35
1.0
0.24
0.001
Florida
64.1
4.7
25.6
0.3
1.5
0.21
0.35
1.35
0.13
0.13
0.1
California
48.2
39.1
10.4
1.4
0.2
0.05
0.6
0.1
0.1
0.05
0.03
Ivry
42.5
39.1
20.7
0.88
1.05
2.0
0.04
0.1
0.36
0.15
CANADA
Bourget Allard
22.4 37.3
36.9 26.3
31.2 30.0
1.0
6.01
0.93 0.004
1.50
0.10
0.55
0.39
Constituents expressed as weight percent.
-------
size, color, dispersibility and photochemical stability.
conditioning agents include potassium, zinc, antimony and calcium
compounds, and phosphate salts. The solution is filtered and the
filtrate is known as weaK acid. Residual acid and iron
originally present in the precipitate are removed with the water
of hydration by calcination. The resulting Ti02 pigment is sent
to finishing operations, which vary acccording to the end product
requirement and application. The wet finishing operations may
include some, or all, of the following steps; repulping, milling,
surface treatment with proprietary agents in solution, washing,
and drying. The alternative dry finishing operations may include
one or more milling steps followed by packaging. A simplified
block diagram of the sulfate process is shown in Figure 14-9.
Water use and Waste Source Inventory
Water use - Water is used in the preparation of titanium
dioxide by the sulfate process for noncontact cooling, air
emission control and for process reactions. In the process, water
is used to leach the soluble sulfate salts from the reaction mass
and to convert the titanyl sulfate to titanium dioxide hydrate.
Water is also used to wash the titanium dioxide hydrate
precipitate free from residual acid and iron. Water is used for
air emission control during the drying of ore, on digester units
and for the cleaning of the kiln gases before they are vented to
the atmosphere. In the digester unit, water seals are used to
maintain a vacuum on the digester units. Large amounts of water
are also used in the finishing operations. Table 14-22 is a
summary of water usage in the titanium dioxide subcategory using
the sulfate process.
Waste sources
A. Digester Sludge: After the digestion of the ore in
sulfuric acid, the resulting sulfates are dissolved in water and
the insoluble impurities are removed in a clarifier or filter.
These include silica, alumina, sulfuric acid and unreacted iron.
The quality of this waste varies and depends on the type and
quality of ore used. Data on the quantity of this waste
indicates that approximately 210 kkg/kkg is produced.
B. Copperas: The recovered ferrous sulfate is marketed or
disposed of as a solid waste. The amount of copperas generated
is about 950 kg/kkg of Ti02. The copperas generally contains
small amounts of adsorbed sulfuric acid.
298
-------
NJ
STRONG-ACID
RECYCLE ,_
WATER ••
STEAM *
*
DIGESTER
WATER ^.
WATER *j
CLARIFIER
k
EMISSIONS to-
SPRAY CON[
WATER to AND VENTURI £
EVAPORATOR H ™^°»* — '
1 WATER *•
|
STEAM to
PRECIPITATION
t
«. icDoa
JCRUBBERS fc«WJfcWl' *"
.^
^jyEHS El-'fLUENT "" ^"
FLASH 1 CONDENSERS pppr riPNT — >•
COOLER 1 „,„„„ — *• EFFLUENT
WEAK-ACID i 1
RECYCLE ^i " 1 J
WATER — to
FIRST MOORE
PTT TPR
STEAM — fcj . j.^..^.. ,
WATER — »>
STEAM *"
WATER *•
STEAM to
DI
SECOND MOORE
FILTER
* STRONG AU1U
WEAK A^TP
^^ _
CALCINER
WET MILL
—EMISSIONS M. COOLING SPRAYS AND ELEC ; WEAR flCID_
WATER toTROSTATIC PRECIPITATORS "
EMISSIONS
WATER *" MIST ELIM
KPirT.llENT
1
JET MILLS
___t,Mlbb!UWti to
JET MILL C
WATER to
TITANIUM
DXIDE PIGMENT
i
PACKAGING
1NATURS "• EFFLUENT ^ -
WATER ^ JET MILL SCRUBBERS ^, EFFLUENT
-WASTO DISPOSAL
T
TO SALES
Figure 14-9. General process flow diagram for production of titaniun dioxide I'jy sulfate process.
-------
TABLE 14-22. WATER USAGE IN TITANIUM DIOXIDE - SULFATE PROCESS SUBCATEGORY
Water Usage per Unit of Production
Uses m3/kkg of Ti02
Non-contact
cooling
Direct process contact
Indirect prc
jcess contact
Plant #555
47.8
390
6
Plant #694
408
588
1.6
Plant #696
149
297
4
(pumps, seals, leaks,
spills, etc.)
Maintenance, equipment 3 1.8 4
cleaning and work area
washdown
Air pollution control 258 78 81
Non-contact ancillary 36 33 NA
uses (boilers, utilities,
etc.)
300
-------
C. Strong Acid Waste: When water is added to titanyl
sulfate solution after the removal of copperas, sulfuric acid and
the hydrate of titanium dioxide are formed. The acid contained
in solution is removed by filtration and the filtrate is known as
strong acid solution. The concentration of sulfuric acid varies
from 15-30 percent as H2S04. In addition to sulfuric acid, the
waste stream contains ferrous sulfate, titania, antimony and
other heavy metal salts. A part of the acid is returned to the
process and the rest sent to the treatment facility.
D. Weak Acid Waste Stream: The waste generated from
washing the titanium dioxide hydrate precipitate is known as weak
acid. The concentration of sulfuric acid in this waste varies
from two to four percent as H2S04 and contains various
impurities, including iron sulfate, titania, antimony and other
heavy metal salts. It also includes, in some cases, the
conditioning agents added to the precipitate prior to washing, to
control and improve the quality of the final product. The weak
acid may also include tne kiln exhaust gas scrubber waste.
E. Scrubber Wastes: Scrubber waste water results from the
scrubbing of vapors emitted during the drying of the ore, during
digestion, and during kiln drying. The amount of waste water
generated depends on the amount of water used and type of
emission controls practiced. The scrubber water contains
titanium dioxide particulates, acid mist, sulfur trioxide and
sulfur dioxide. Of all the waste produced from titanium
dioxide-sulfate process manufacture subcategory, the scrubber
waste water constitutes the major portion.
F. Wet Milling Waste: These wastes are generated during
wet finishing of the titanium dioxide pigment. Wet milling is
used to produce pigment particles of the desired size and surface
character and requires steam and water for repulping the pigment.
Caustic soda is also used to remove any residual acidity from the
titanium dioxide pigment during the finishing operation. The
waste water from wet finishing operations, therefore, contains
titania, sodium sulfate and other agents added to improve or
achieve desired properties in the final product.
Control and Treatment Practices
BPT: The recommended technology for 3PT is neutralization
of the Ti02 sulfate process waste waters with lime or caustic
soda and removal of suspended solids in settling ponds or
clarifier-thickener combinations.
Plant #559 was sampled in the screening and verification
301
-------
phase. At this plant the strong acid is sent to a lined holding
pond for equalization. The effluent from the pond is neutralized
with ground calcium carbonate in a reactor; just a sufficient
amount is added to raise the pH to a level such that calcium
sulfate, but not ferrous hydroxide, is precipitated. The C02
formed during the reaction is vented to the atmosphere and the
calcium sulfate slurry goes to a clarifier. The underflow Eron
the clarifier is filtered to produce pure gypsum crystals at a
concentration of 70-80 percent.
The weak acid is sent to a settling pond, where it is
combined with a small quantity of other wastes. The effluent
from the weak acid pond is mixed with the calcium sulfate
clarifier overflow and neutralized with ground calcium carbonate
in a three-stage reactor. Pebble and slaked lime are also added
to raise the pH and precipitate more calcium sulfate. Air is
also introduced to convert the ferrous iron to ferric. The
effluent from the reactor goes to another clarifier, and the
clarifier underflow is filtered to concentrate the solids to 70
percent. The overflow from the second clarifier is mixed with
the other process waste waters. These include the scrubber,
finishing and cooling waste waters. The combined water is
neutralized with slaked lime before it is sent to a final
settling pond, the effluent from which is discharged. Figure
14-10 gives the flow diagram of the treatment process and shows
the sampling locations for both screening and verification.
Table 14-23 gives the flow data for the waste streams and
significant pollutant emissions.
At Plant #555, all the process effluent goes to a settling
basin, the effluent from which is discharged. The solids are
dredged and accumulated on the plant property. Future plans are
to dispose of the solids in an approved landfill.
At Plant #694, the clarification sludge which contains the
unreacted ore is sent to waste disposal. The weak acid effluent
from the plant is neutralized with slaked liiae and the grit is
settled out for landfill disposal. After the separation of grit,
the aqueous stream is discharged to a municipal treatment system.
The other wastes, together with runoff from the plant site, are
collected and sent to a lagoon for solids removal, and the
overflow discharges to a river.
At Plant #696, the raw wastes are sent to thickeners to
remove the suspended solids and the overflow is discharged.
Depending on the titanium content, the underflow from the
thickeners is either recycled or disposed of in a landfill.
At Plant 4605, the process raw waste streams are combined
and sent to a reactor for neutralization with a water slurry of
finely ground calcium carbonate. The effluent from the reactor is
hydrocycloned into three fractions. The first fraction, which is
302
-------
OTHER PRODUCT
WASTE WATER
WEAK ACID 1
WASTE STREAM
-e-
«4
U)
o
U)
STRONG ACID—^
WASTE STREAM
SOLIDS TO
STORAGE/
LANDFILL
PRODUCT
WASTE WATER
TiO, (SULFATE PROCESS)
SCRUBBER
WASTE WATER
) Waste streams sampled.
SOLIDS
TO
STORAGE/LMCFILL
Figure 14-10. General flow diagram at Plant 1559 showing the sampling points.
Titanium Dioxide (Sulfate Process)
-------
TABLE 14-23 . FLOW AND POLLUTANT CONCENTRATION DATA OF THE WASTE STREAMS
SAMPLED FOR PLANT #559 PRODUCING TITANIUM DIOXIDE (SULFATE PROCESS)
Stream
No.
Sampled
Stream
Description
Unit
Flow
m /kkg
of TiO
SS
Load
kg/kkg
of TiO-
Iron
Load
kg/kkg
of TiO_
Chromium
Load
kg/kkg
of TiO~
Weak Acid Pond
Overflow
Strong Acid Pond
Overflow
Scrubber and
other Product
Waste Water
Final Treatment
Effluent
107
305
<«
9.7
1.94
87.6
0.18
583
183
(1)
83.6(1) 0.062(1)
700(1)'(2) 16.1
3.08
0.017
(1) = The pollutant load was calculated by multiplying the flow contributed
by the sulfate process stream times the concentration of pollutant.
Pollutant Load = (total stream flow)x(fraction contributed by sulfate
process waste) x stream pollutant concentrated.
(2) = While calculating the unit flow the contributions to the treatment
process from precipitation, the water in the treatment chemicals,
losses from evaporation and from solids leaving the process nave
not been considered.
304
-------
the coarse gypsum slurry, is separated from the reactor effluent
at a concentration of 85-90 percent, and placed in a
self-draining dewatering system. The "dry" solids are finally
trucked to a landfill. The second fraction separated in the
hydrocyclone is a fine gypsum slurry which is recycled to the
neutralization reactor. The residual gel slurry forms the third
fraction, and this is sent to a thickener after C02 degassing. A
flocculating agent is added to the flow to the thickener to
oromote solids separation and thickening. The underflow (from the
thickener is centrifuged and the solids landfilied. The filtrate
from the centrifuge is recycled to the thickener, and the
thickener overflow is discharged.
Evaluation of Industry Production and Waste Flow Data
The volume and characteristics of waste water streams from
different sulfate process titanium dioxide plants do not differ
yreatly. Some variations, however, are noted as a result of
differences in ore qualities, in location and in process details.
The majority of the dissolved pollutants in waste water from this
segment of the Ti02 industry consist of acidity and iron.
Segregation of the waste water is important for control and
treatment practices and aids in developing economically feasible
treatment systems. Generally, weak and strong acid stream are
segregated from each other as well as from the less contaminated
waste waters which include contact cooling, scrubbing and some
finishing operation wastes. The unit flows for the segregated
raw waste streams at different facilities are shown in Table
14-24. Waste characteristics for Plant #555 are given in Table
14-25.
Process Modifications and Technology Transfer Options
Specific process modifications cannot be made at present.
However, several areas for further research suggest themselves.
They are:
1. One of the waterborne wastes, the strong sulfuric acid
produced from the Ti02 sulfate process, has a sulfuric acid
concentration that varies from 15-30 percent as H2S04.
Currently, only a small portion of it is recycled. Research is
needed to find cost-effective ways to concentrate the acid to 90
percent and to eliminate the impurities (especially iron) so that
it can be reused in the digester. This will eliminate much of
the alkali requirements for neutralization and relieve disposal
problems associated with solid waste gypsurn.
2. Economical methods need to be developed for the recovery
°f iron oxide, aluminum and vanadium from the waste to the extent
305
-------
TABLE 14-24. EFFLUENT FLOW AT PLANTS #555, #605 AND #559 PRODUCING
TITANIUM DIOXIDE (SULFATE PROCESS)
Waste Stream Flow in m /metric ton of TiO at plant
Plant #555 Plant #605 Plant #559
Strong Acid 8.49 7.8 7.4
Weak Acid 78.2 93 85
Other process waste water 362 597 NA
NA = Not Available
306
-------
14- 25. RAW WASTE CHARACTERISTICS (INDUSTRY DATA) FOR PLANT #555
(PRODUCTION OF Ti02 BY SULFATE PROCESS)
— • ' '
Waste Source Unit
Flow
m /kkg
of Ti02
Digestion 115
Clarification 3 . 58
Evaporation 113
Cooling 20
Strong Acid from 8.49
first Moore Filtration
Weak Acid from 12.2
first Moore Filtration
Weak Acid from 10.4
second Moore Filtration
Weak Acid from 12.0
first stage
Calcination
Weak Acid from 40.0
second stage
Calcination
Calcination Mist 38.7
Eliminators
Wet Milling Washing 11.1
and Drying
Jet-Mill Condenser 27.0
Jet Mill Scrubbers 18.0
Boiler and Water 16.6
Pollutant Waste Loads, kg/kkg of Ti00
*
PH
3.0
2.5
4.0
6.1
<0.5
2.0
1.7
2.0
2.2
3.0
8.0
6.5
7.4
9.0
Acidity
(as H2S04)
20.8
26.7
18.7
2.49
2.360
88.3
148
20.8
19.2
7.50
_
-
-
-
NH3 Fe
(as N)
0.042
8.42
1.14
0.099
- 139
3.8
0.29
0.22
0.64
0.02
8.6 0.01
0.01
0.13
-.66
TSS
9.3
175
3.2
0.46
0.959
0.23
0.13
2.0
4.92
0.21
2.13
1.1
1.7
5.25
£,
TDS
35.7
40.8
20.2
3.09
2.815
98.8
151
7.50
33.1
27.9
11.0
2.7
3.58
8.92
Plants
Value in pH units.
307
-------
that markets are available for these materials.
3. If markets could be developed for the sale of ferrous
sulfate (copperas) , solid waste disposal problems would be
reduced. Currently, a portion is sold and the rest disposed of
as a solid waste.
Best Management Practices
1. Storm water runoff from the plant site and surrounding
areas can be collected and sent to the treatment facility.
Model Plant and BPT Level Treatment System Specifications
Model plants were selected to provide the basis for cost
estimates. The rationale used for their selection is given
below.
Production - Five plants produce titanium dioxide by the
sulfate process at a total production rate of 246,000 metric tons
per year. Production ranges from a minimum of 31,000 kkg/yr to a
maximum of 74,500 kkg/yr with a mean of 49,000 kkg/yr and a
median of 43,000 ki
-------
one-third (100 kg/kkg of Ti02) was soluble ferrous iron. The
unit sulfate and suspended solid loadings for the different waste
,vater streams for the model plant were:
Sulfate Loading T3S Loading
Stream kg/kkg of Ti02 Kg/kkg of Ti02
Weak Acid
Strong Acid
Other Waste Water
2,300
1,800
Neglig ible
300
3
25
Chemicals Us ed: In the model BPT system, powdered limestone
is used for first stage neutralization of mixed strong and weak
acids, at the unit rate of 3,000 kg/kkg of Ti02. Pebble lime
(CaO) is used for second stage neutralization of the mixed acid
streams and for final neutralization of the total combined flow,
including the other miscellaneous wastes. The unit application
of CaO for all purposes is .235 kg/kkg of Ti02. In Level 2
(BAT) , soda ash is added to 45% of the "other waste" flow at an
approximate dosage of 130 ug/1, to permit partial recycle for
miscellaneous purposes.
Sol ids Produced; Although some existing plants have
attempted to produce two grades of saleable gypsum from the
strong and weak acid streams, at present there is not a
sufficient market for gypsurn to justify byproduct gypsum recovery
in the model plants. The solids produced from the treatment
facility consist of gypsum, iron oxide, and the original
suspended solids introduced in the influent. The total solids
produced in the model plant are assumed to be 5,500 kg/kkg of
Ti02.
Additional solids generated in the soda ash treatment of
"other wastes" at Level 2 are only a few hundred pounds per day,
and are considered a negligible increase in total solids
production. These additional solids are periodically transferred
from the recycle polishing ponds to the main treatment system
just ahead of the aeration step. In this way, the additional
quantity of priority metals will be subjected to the ferric iron
flocculation, lime treatment and settling sequence in the BPT
system.
309
-------
14.4 TECHNOLOGY BASED POLLUTION ABATEMENT
14.4.1 Advanced Level Treatment Applications
Selection of Technology to be Applied
Sulfate process - BPT - Two levels of treatment are shown
for the sulfate process model, utilizing calcium carbonate
neutralization for the blended strong and weak acid streams. The
priority pollutants are precipitated and together along with
gypsum are separated in first-stage thickeners. Aeration then
oxidizes any ferrous iron present and removes C02 before mixing
with miscellaneous plant wastes containing minor amounts of heavy
metal priority pollutants. The combined stream is then given
lime treatment to pH 9 and settled in polishing lagoons before
discharge. This three-step system is patterned after existing
systems which separate the acid streams from miscellaneous wastes
in order to make possible the recovery of pure and impure gypsum
from the relatively consistent acid streams. Alkaline
precipitation of heavy uietals, and significant removal of arsenic
occur during the last two stages of lime neutralization, and
settling of precipitated priority pollutants occurs in the final
polishing lagoons. Because waste flow rates are unusually high
in the sulfate process, long-term lagoon settling is more cost
effective than dual media filtration. The mechanical aeration
step used for oxidizing ferrous iron may contribute an important
mechanism for the simultaneous removal of other heavy metals
present very similar to the ferrite coprecipi tation method
described in the Treatment Technology Assessment section.
Although the Model Plant does not include equipment for
gypsum recovery, it is based on separation of waste streams,
making pure or impure gypsum recovery possible by intercepting
thickener underflow(s) . Recovery of gypsum as a saleable
by-product is not possible since no market exists.
Level 2_ - Level 2 for the sulfate process employs the
described BPT treatment for strong acid, weak acid and 55% of the
"other wastes". The remaining other wastes receive soda ash
treatment and settling, to permit recycling a nonscaling effluent
for scrubbers and miscellaneous uses. Heavy metal pollutants in
the separated recycle stream are settled as carbonates and
periodically removed to a secure landfill.
Equipment functions - Treatment of waste water from the
sulfate process involves the mechanized handling of large
quantities of chemicals and reaction products, primarily gypsum.
The BPT model includes rail car deliveries of
limestone and lime, bucket elevators, storage bins, multiple
310
-------
feeders, mechanical feeders, mechanical aerators and two-stage
thickening for removal of pure and iron-bearing gypsum from the
treated acid waste streams. Calcium saturated thickener overflow
and miscellaneous other waters are subjected to alkaline
precipitation and settled in a one-day polishing pond. In Level
2, to reduce the mass discharge of heavy metals, only 55% of the
BPT "other waste" flow joins the treated acid waste stream, for
BPT treatment as described above. However, the remaining 45% of
"other wastes" is given separate treatment with soda ash settled
in a lagoon, for recycle to miscellaneous scrubber and noncontacc
cooling purposes. Treatment of the strong and weak acid streams,
including oxidation and settling of ferrous iron, remains the
same as in the BPT model.
Chemicals and handling - Sulfate PfJ^E.6^. ~ First stage
neutralization employs ground limestone, while lime is used for
second stage and final alkaline precipitation. Oxygen is
supplied from atmospheric ai, and polymer is added to assist in
the second stage settling of iron hydroxide. Aside from the bulk
handling of large amounts of these common chemicals, there are no
special hazards involved in their use.
Separation and removal p_f_ solids - Large quantities of
thickener underflow are pumped to spreading areas for
consolidation of the solids, which are later pushed into 18 foot
high piles on land provided for 10 years of operation. Solids
from occasional draining of the polishing lagoon and the Level 2
recycling lagoon are returned to the aeration step of the waste
acid streams, after which they will be settled out in the second
stage thickener, being handled as part of the thickener
underflow. Although no dewatering equipment is provided, the
first and second stage thickeners can be sources of pure and
impure gypsum for future by-product recovery.
Monitoring requi rements - The same monitoring requirements
apply as for the chloride " process, with the addition of the
internal process needed to monitor the scaling tendency and total
dissolved solids in the recycled "other wastes", in order to keep
the recycle stream at a suitable level of mineral content.
Figures 14-11 and 14-12 show the raodel treatment systems
ohosen for this subcategory.
14.4.2 Base Level Performance Chajrac t e r 1st i cs for BPT Pollutant
Removal
The production of titanium dioxide by the sulfate process
generates extremely large waste loads of sulfuric acid and
ferrous sulfate, as well as considerable quantities of suspended
solids. Effective control and treatment of these
wastes — comprised of segregation of the most highly contaminated
311
-------
OJ
GROUND
UWKSTONE
CaCO
EFFLUENT
WASTE WATER
SOUDS DISPOSAL
ONSITE
Include* flow monitoring, pll monitoring and sampler
Figure 14-11. Han to water treatment Level I for titan Urn d lax tele - BulfaLe process.
-------
CO
GROUND
LIMESTONE
CaCO
RAPID MIX AND SETTLING
RECYCLED EFFLUENT
WASTE WATEIi
WASTE WATEJ
»\STRONO ACID/ jQP»-
[•EI^ '
/ monitoring, pH monitoring and aamplcr
figure 14-12. Waste water treatment Level 2 for titanium dioxide - aulfate proceaa.
-------
effluents, neutralization, aeration to oxidize ferrous iron, and
removal of the resulting precipitates—is presently practiced at
only one of the five existing plants and is being implemented at
another.
Waste water control treatment practices at three
sulfate-process titanium dioxide plants are summarized in Table
14-26. Of the two direct discharging facilities, only Plant #559
currently provides effective treatment for all process waste
streams.
At Plant #605, implementation of treatment equivalent to
that provided at Plant #559 is in progress, but presently only
neutralization and solids removal is practiced. Consequently,
effluent loadings of iron at that facility are very high.
Effluent quality monitoring data from plant 4559 are
summarized in Table 14-27. Verification sampling results for
this plant are presented in Table 14-28.
Raw waste priority pollutants found in significant
concentrations at Plant #559 which might require regulation,
include arsenic, cadmium, chromium, copper,- nickel, thallium, and
zinc.
BPT technology for sulfate process titanium dioxide wastes
has been identified as multiple stage neutralization of acid
wastes with limestone and lime, aeration for removal of ferrous
iron, and settling. On site disposal of gypsum sludges generated
in treatment is included.
Chloride-Ilmenite process
Two plants currently use the chloride ilmenite process for
manufacture of titanium dioxide. Plant #550, sampled in
screening, disposes of its most contaminated acid waste by
deep-well injection and treats the remaining wastes by
neutralization and settling. Results of analyses indicated that
treatment influent and effluent waste loads resembled those
observed at other chloride process plants, while the acidic
ferric chloride waste contained waste loads similar to those
encountered at sulfate process plants. Unfortunately, during the
sampling program, the ore being used at the plant was closer to
the richer rutile ore and could not be considered a true
ilmenite. Conclusions could therefore not be drawn on the basis
of this sampling as to the character of chloride ilmenite waste
loads. Company personnel indicated that such variation in ore
quality is likely for some time in the future.
It can be suggested that until further studies are conducted
and decisions are made as to the continued use of deep well
314
-------
14-26. SUMMARY OF EXISTING CONTROL AND TREATMENT TECHNOLOGY FOR
SULFATE-PROCESS TITANIUM DIOXIDE PLANTS
Plant Process Control and Treatment Technology Discharge
Wastes-breams Status
#559 Strong and Weak Acids; Waste acids are neutralized, settled Direct
Contact Cooling: (in stages) and aerated for iron
Noncontact Cooling removal. Cooling water is mixed with
neutralized acid for final neutral-
ization and settling before discharge.
1605 Strong and Weak Acids; Currently, waste acids are adjusted Direct
Contact Cooling to pH 4 and settled, but a system
using aeration and further neutral-
ization with settling is under
construction. Contact cooling water
is neutralized for discharge.
#694 Weak Acid Weak acid waste water is adjusted POTW
to a pH of greater than and dis-
charged to sanitary sewer.
315
-------
TABLE 14-27 SUMMARY OF DAILY EFFLUENT MONITORING DATA FOR COMBINED WASTE
WATER TREATMENT DISCHARGE AT SULFATE-PROCESS TITANIUM DIOXIDE
PLANT #559
Parameter
Chromium, Cr
Cadmium, Cd
Iron,Fe
(Total)
Iron,Fe
(Dissolved)
Lead,Pb
Nickel, Ni
Zinc,Zn
Min
0.01
0.001
0.4
0.08
0.002
0.01
0.01
Concentration
(mg/D
Avg Max
0.
0.
3.
0.
0.
0.
0.
021
009
25
279
017
029
027"
0.
0.
19.
4.
0.
0.
0.
119
02
1
98
05
08
3
St. Dev.
0.
0.
4.
0.
0.
0.
0.
027
004
6
562
013
02
057
0.
0.
0.
0.
0.
0.
0.
Waste Load
(kg/kkg) (lbs/1000 its)
Min Avg ifoy
00049
00004
29
04
00008
00057
00049
0.0014
0.00062
2.14
0.194
0.0012
0.0019
0.0019
0.0045'
0.0012
12.99
4.0
0.003
0.0046
0.022
Total Suspended
Solids, TSS
35.8
61.3
23.9
316
-------
14-23 . VERIFICATION RESULTS TITANIUM DIOXIDE PLANT 1559
Pollutant
Total Suspended
Solids (TSS)
Total Iron, Fe
Antimony, Sb
Arsenic, As
Cadmium , Cd
Chromium, Cr
Copper, Cu
Lead, Pb
Nickel, Ni
Thallium, Tl
Zinc, Zn
Raw Waste
kg/kkg
Avg. Max.
310
670
-
0.015
0.008
5.0
0.13
0.16
0.19
0.004
0.72
330
770
-
0.020
0.001
5.6
0.14
0.17
0.22
0.008
0.76
Treated Effluent
mg/1 kg/kkg
Avg. Max. Avg.
23
4.4
<0.015
<0.010
0.0001
0.025
<0.005
0.002
<0.005
<0.005
0.061
38
7.9
<0.015
<0.010
0.0002
0.030
<0.005
0.003
<0.005
<0.005
0.065
19.5
3.7
<0.01
<0.008
0.0001
0.02
<0.004
0.002
0.004
0.002
0.05
Flow (m3/kkg) 616"
*
Includes cooling water and a small part of chloride process waste.
317
-------
injection for disposal of this acidic wastes, discharge
limitations be either reserved or set similar to those
limitations for the sulfate process.
Base Level Performance Characteristics for BPT and Priority
Pollutant Removal
Table 14-29 presents effluent quality achievable through the
implementation of BPT or Level 1 treatment technology for
titanium dioxide manufacture by the sulfate process.
Pretreatiaent Applications
Presently one sulfate process titanium dioxide plant
discharges a portion of its waste water to a POTW. However, due
to the large volumes of waste water, the highly acidic nature oE
the raw wastes, and the great amounts of solids generated in
neutralizing the wastes, it is unlikely that there will be
further POTW discharge of wastes from titanium dioxide sulfate
process plants. If they need to be regulated, BPT standards
should be applied.
Responses to Remand Issues
Effluent limitations originally promulgated as BPCTCA for
sulfate process titanium dioxide plants were remanded on the
grounds that an inadequate technical basis was provided for the
regulations, and that the technology was neither explicitly
identified nor in use within the industry. Treatment
technologies have now been clearly identified and demonstrated.
Achievable levels of pollution control have primarily been
derived from results presently achieved in the industry.
Treatment cost estimates and energy requirements were also
challenged. Cost estimates for the selected technology have been
developed, including the costs of solid waste disposal and all
energy required for waste treatment.
14.4.3 Estimated Performance for Advanced Level System
Table 14-30 presents estimated achievable effluent quality
through implementation of the recommended advanced technology of
recycle.
318
-------
TABLE 14-29 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Titanium Dioxide - Sulfate Process
Level of Treatment: 1
Waste Water Flow: 700 m3/kkg
Quality Limit Emission Limit
Subcategory (1) (mg/1) (kg/kkg)
Pollutant Performance VFR
(mg/1) 30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants;
Total Suspended 86 2.0 37.5 75 26 52
Solids, TSS
Iron, Fe 4.6 3.0 5.0 15 3.5 10.5
Proposed Priority
Pollutants
Arsenic, As
Cadmium, Cd
Chromium, Cr
Copper, Cu
Lead , Pb
Nickel, Ni
Thallium, Tl
Zinc, Zn
0.
0.
0.
0.
0.
0.
<0.
0.
01(2)
01
04
01(2)
03
05
005 (2)
06
2.
2.
2.
2.
2.
2.
2.
2.
0
0
0
0
0
0
0
0
0.
0.
0.
0.
0.
0.
0.
0.
5
1
1
5
5
5
2
5
1.0
0. 2
0. 2
1.0
1.0
1.0
0.4
1.0
0.
0.
0.
0.
0.
0.
0.
0.
35
07
07
35
35
35
14
35
0.
0.
0.
0.
0.
0.
0.
0.
7
14
14
7
7
7
28
7
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) Verification sampling
319
-------
TABLE 14-30 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Titanium Dioxide - Sulfate Process
Level of Treatment: 2
Waste Water Flow: 430 m3/kkg
(1)
rPyo = 4-=aJ~,-]T 1 f- \7 VP R
(mg/1)
Quality Limit
(mg/1)
30 day 24 hr
Aver Max
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
BPT Pollutants:
Total Suspended
Solids, TSS
Iron, Fe
Proposed Priority
Pollutants
Arsenic , As
Cadmium, Cd
Chromium, Cr
Copper, Cu
Lead , Pb
Nickel, Ni
Thallium, Tl
Zinc, Zn
37.
5.
0.
0.
0.
0.
0.
0.
0.
0.
5
0
5
1
1
5
5
5
2
5
2.
3.
2.
2.
2.
2.
2.
2.
2.
2.
0
0
0
0
0
0
0
0
0
0
37.
5.
0.
0.
0.
0.
0.
0.
0.
0.
5
0
5
1
1
5
5
5
2
5
75
15
1.
0.
0.
1.
1.
1.
0.
1.
0
2
2
0
0
0
4
0
16
2.
0.
0.
0.
0.
0.
0.
0.
0.
2
22
043
043
22
22
22
086
22
32
6.4
0.43
0.086
0.086
0.43
0.43
0.43
0.17
0.43
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
320
-------
14.4.4 Cost Estimates - Sulfate Process
Model Plant Costs
The estimated costs for three models having different
production levels are given in Tables 14-31, 14-32, and 14-33.
Annual treatment costs as a function of production are shown
graphically in figure 14-13. Similarly, treatment cost per
metric ton of product is given in figure 14-14.
Table 14-34 presents a summary of the unit cost distribution
between amortization and operation and maintenance cost
components at different productions and at the BPT and BAT (2nd)
level of treatment.
For existing sources at the first level of treatment, the
disposal of sludge is on-site, hence land requirements are fairly
large. Amortization, chemicals, labor, residual waste disposal
costs have significant impact on the annual costs. The treatment
Level 2 amortization, chemicals and labor constitute a major
portion of the additional costs.
321
-------
TABLE 13-31. MODEL PLANT TREATMENT COSTS
Subcategory TITANIUM DIOXIDE Sulfate Type of Regulation BAT
Production 31,800 metric tons per year ( 35,059 tons per year)
90 metric tons per day ( 100 tons per day )
Waste water flow 61600 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $701,200 $117,500
Equipment in place,
including piping,
fittings, electrical
work and controls 2,328,400 233,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 607,720 70,100
Incidentals, overhead,
fees, contingencies... 607,720 70,100
Land 1,272,000 12,000
TOTAL INVESTMENT COST $5,526,040 $502,700
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $504,000 $56,000
Energy 96,000 9,000
Chemicals 1,589,000 176,000
Maintenance 425,404 49,070
Taxes and insurance... 165,781 15,081
Residual waste
disposal 210,000
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $3,005,185 $312,651
C. AMORTIZATION OF
INVESTMENT COST $692,132 $79,836
TOTAL ANNUAL COST $3,697,317 $392,487
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
322
-------
TABLE 14-32. MODEL PLANT TREATMENT COSTS
Type of Regulation BAT
Subcategory TITANIW DIOXIDE Sulfate
Production 47,700 metric tons per year ( 52,589 tons per year)
136 metric tons per day ( 150 tons per day )
Waste water flow 92600 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $958,700 $161,000
Equipment in place,
including piping,
fittings, electrical
work and controls 2,980,200 278,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 789,580 87,800
Incidentals, overhead,
fees, contingencies... 789,580 87,800
Land 1,920,000 18,000
TOTAL INVESTMENT COST $7,447,060 $632,600
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $672,000 $56,000
Energy 138,000 12,000
Chemicals 2,384,000 265,000
Maintenance 552,706 61,460
Taxes and insurance... 223,411 18,978
Residual waste
disposal 315,000
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $4,300,117 $420,938
C. AMORTIZATION OF
INVESTMENT COST $899,252 $99,995
TOTAL ANNUAL COST
$5,199,369
$520,933
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
323
-------
TABLE 14-33. MODEL PLANT TREATMENT COSTS
Subcategory TITANIUM DIOXIDE Sulfate
Production
Type of Regulation BAT
74,500 metric tons per year ( 82,136 tons per year)
212 metric tons per day ( 234 tons per day )
Waste water flow 144000 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, contingencies...
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Maintenance
Taxes and insurance...
Residual vaste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
LEVEL OF TREATMENT*
FIRST SECOND
$1,293,500
3,914,500
9,000
1,043,400
1,043,400
2,940,000
$10,243,800
$672,000
199,000
3,719,000
730,380
307,314
420,000
15,000
$6,062,694
$1,188,328
$7,251,022
$208,000
322,000
106,000
106,000
24,000
$766,000
$56,000
18,000
412,000
74,200
22,980
7,500
$590,680
$120,723
$711,403
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
324
-------
LEVEL ft
LEVEL #1
o
o
o
o
o
H
X
7 /
/
y
30
40 50 60 70
PRODUCTION, METRIC TONSAEAR X 1000
80
Figure 14-13. Annual treatment cost vs. production for the
Titanium Dioxide Subcategory, Sulfate Process
325
-------
1 "^fi
110
inn
Qn
2
,
: i
• '
• i ,
i !
|
! ' ' '
i
i
! ,
! | ; !
I
1 : ' 1
•
! ': i
,
1 1
U J
(§
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\
\
\
• !
n '
*V i
i X
i X
' \
; i
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i i
' 1 I
! i
; i
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1 i ' '
i
,
1 1
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i i ! !
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ill:
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\_
\
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• ;
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j i l x
i i !
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1 !
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!
1
X ;
X
X
X
i , , ;
s^ !
X
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- ;
; i ' ,
i ;
1
: i
'
' *
, i
•
0
1
!
1
k. LEVEJ
X
®
! '
i :
:
1 1
i . '
\ :LEVE.
iXgji :
^ .
' ,
! ' ! i
! i ; i
.
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-. #1 :
1
i i i
, i
0
PRODUCTION, METRIC TONSAEAR x 1000
Figure 14-14. Annual unit treatment cost vs. production for the
Titanium Dioxide Subcategory, Sulfate Process
326
-------
TABLE 14-34 MOEEL PLANT TREATMENT COSTS
Subcategory TITANIUM DIOXIDE Sulfate Type of Regulation BAT
Annual Treatment Costs ($/kkg)
LEVEL OF TREATMENT
PRODUCTION FLOW FIRST SECOND THIRD FOURTH
(kkg/yr) (m3/day) $ $ $ $
Annual Operation
and Maintenance
Annual
Anortization
Total Cost
31,800 61,600 94.50 9.83
47,700 92,600 90.15 8.82
74,500 144,000 81.38 7.93
31,800 61,600 21.77 2.51
47,700 92,600 18.85 2.10
74,500 144,000 15.95 1.62
31,800 61,600 116.27 12.34
47,700 92,600 109.00 10.92
74,500 144,000 97.33 9.55
Not Applicable
327
-------
SECTION 15
ALUMINUM FLUORIDE INDUSTRY
15.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
15.1.1 Industrial Profile and Analytical Results
Aluminum fluoride is used as a raw material in the
production of cryolite (sodium fluoroaluminate) , which in turn is
used in the production of aluminum. Aluminum fluoride is used
also as a metallurgical flux (for welding rod coatings) , as a
ceramic flux (for glazes and enamels), and as a brazing flux (for
aluminum fabrication) .
The industry profile data
Table 15-1, while the existing
15-2.
for this subcategory is given in
regulations are given in Table
Priority pollutants
waste during sampling
follows:
found at significant levels in the raw
at Aluminum Fluoride plants were as
Pollutant
Maximum Concentration Observed
(ug/1)
Screening Verification (2 Plants)
Arsenic
Selenium
Chromium
Copper
Cadmium
Mercury
Nickel
200
110
77
120
0.85
2
150
475
97
1135
235
33
11
285
A summary of daily and unit product raw waste loads for all
plants sampled can be found in Table 15-3. Individual plant raw
waste loads per unit product found in sampling can be found in
Table 15-4.
Based on the total annual production of this subcategory and
the average waste load generated per unit product, the estimated
total priority pollutant raw waste loads generated each year for
this subcategory are as follows:
328
-------
TABLE 15-1
SUBCAIEGORY PROFILE DATA .
SUBCATEGORY
ALUMINUM FLUORIDE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
7
6
204,800 kkg/year
143,400 kkg/year
38 kkg/year
45,600 kkg/year
24,300 kkg/year
35,500 kkg/year
69 percent
5 years
21 years
539 cubic meters/day
2,200 cubic meters/day
12 cubic meters/kkg
22 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
329
-------
TAELE - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SDBCM Muminum Fluoride
SUBPAJ W (40CFR 415.230, 5/22/75)
STANDARDS
BPCTCA* BATEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
Prcdui Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Proce meters (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
A1F-, „-, ., 0.68 0.34
3 Fluoride (40.0)** (20>0)
0-86 0.43
(50.6) (25.3)
Aluminum 0.34 0.17
(20.0) (10.0)
*
Sectl5.230, 415.231, and 415.232 were revoked by the Agency
(4101, November 23, 1976).
"Maxcimum of any one day.
2
Avgarage of daily values for thirty consecutive days shall not exceed.
**flcs 17,000 1/kkg.
330
-------
TABLE 15-3.
SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
UJ
H
SUBCATEGORY
Pollutant
Priority
Arsenic, As
Cadmium, Cd
Chromium^ Cr
Copper, Cu
Nickel, Ni
Mercury, Hg
Selenium, Se
Conventional
TSS
Fluorine, F
Aluminum, Al
ALUMINUM FLUORIDE
Minimum
0.071
0.072
0.02
0.025
0.0013
0.051
751
493
98.4
kg/day
Average
0.078
0.010
0.16
0.16
0.13
0.0041
0.11
2921
727
220
Loadings
Maximum Minimum
0.086 0.0007
0.25 0.0016
0.33 0.0002
0.26 0.00025
0.0095 0.000027
0.17 0.001
5510 16.3
986 9.71
352 0.97
kg/kkg
Average
0.0016
0.0002
0.0035
0.0033
0.003
0.00005
0.0015
53.7
11.9
4.40
No. of Plants
Maximum Averaged
0.002 3
1
0.0054 2
0.0071 3
0.0056 3
0.00009 3
0.002 2
-------
TABLE 15-4. PRIORITY POLLUTANT RAW WASTE LOADS (in kg/kkg of Product)
—
SUBCATEGORY
POLLUTANT
Arsenic, As
Selenium, Se
Chronium, Cr
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel, Ni
Zinc, Zn
ALUMINUM FLUORIDE
#705
0.002
0.001
0.0016
0.0027
0.0004
0.000036
0.003
0.008
PLANT
#705
0.002
0.0054
0.0071
0.001
0.000027
0.0056
0.0047
0.0002
#251
0.0007
0.002
0.0002
0.00014
0.00009
0.00025
0.00046
332
-------
Pollutant Waste Load (kg/year)
W MMr .• —» —• -» -«• •» — «•» ••"• •" ™ ™" "• "™ ^ "™ •"• "* ™" ™" "™ "™" ^ *™ ^ "™ "" ^ "™ "™ "* "™ *™
Arsenic 190
Selenium 180
Chromium 420
Copper 400
Mercury 6
Nickel 360
15.1.2 Process Waste Sources and Waste Water Treatment Data
General Process Description
Raw material and process - In the dry process for the
manufacture of aluminum fluoride, partially dehydrated alumina
hydrate is reacted with hydrofluoric acid gas. The reaction is
given as:
A1203 + 6HF = 2A1F3 + 3H20 (1)
The product, aluminum fluoride, is formed as a solid, and is
cooled with non-contact cooling water before being sent for
milling and shipping. The gases from the reactor are scrubbed
with water to remove unreacted hydrofluoric acid before being
vented to the atmosphere. A simplified flow diagram of the
process is shown in Figure 15-1.
Water uses - Water is used in noncontact cooling of the
product, for seals on vacuum pumps and for scrubbing the reacted
gases before being vented to the atmosphere. Water is also used
for leak and spill cleanup and equipment washdown. Table 15-5
gives a summary of water usage in the aluminum fluoride industry.
Sources of waste water
A. Noncontact cooling water - Noncontact cooling water is
used to cool the product coming out of the reactor. In some
cases it is recirculated and the blowdown treated separately froai
other process contact wastewater or discharged without treatment.
The water can be monitored for fluoride and if process
contamination occurs it can be diverted to the waste water
treatment facility for fluoride removal.
B. Floor and equipment washings - The quantity and quality
of waste water generated from those operations is variable and
depends largely on the housekeeping practices at the individual
pi an ts.
333
-------
U)
bo
HYDRATED
ALUMINA
HYDROGEN
FLUORIDE
WATER
j VENT
SCRUBBER
CYCLONE
REACTOR
WASTE WATER
NONCONTACT
COOLING WATER
J *
COOLER
PRODUCT
COLLECTION
AND STORAGE
ALUMINUM
•FLUORIDE
PRODUCT
Figure 15-1. General process flow diagram for production of aluminum fluoride.
-------
TABLE 15-5. WATER USAGE IN THE ALUMINUM FLUORIDE SUBCATEGORY
Source Water use per unit of production
m /kkg of AlF.,
Plant Plant Plant Plant
# 837 # 705 # 188 # 605
Non-contact cooling 14.45 NA 6.95 NA
Indirect process 12.21 1.15 NA NA
contact (pumps, seals,
leaks, spills)
Maintenance, e.g. 1.13 2.4 NA 1.60
cleaning and vrork area
washdown
Scrubber 9.52 3.46 19.95
NA = Not Available.
335
-------
C. Scrubber waste water - This is the major source of waste
water requiring treatment before being discharged or recycled
back to the scrubber. It is contaminated with hydrofluoric acid,
aluminum fluoride and aluminum oxide, and, in some cases, the
presence of sulfuric acid and sil icotetraf luo r ide has been
detected. These originate as impurities in the hydrofluoric acid
used in the process. Table 15-6 gives the range of waste water
flows at different facilities.
Treatment System Description
The Best Practicable Technology - BPT consists of
neutralization with lime to precipitate fluoride as calcium
fluoride, followed by settling to remove suspended and
precipitated solids.
Treatment practices - Plant #705 practices lime
neutralization and settling of the waste waters. Since aluminum
fluoride production is integrated with hydrofluoric acid
production, the waste waters from the two processes are combined
before treatment. The plant does not treat noncontact cooling
water.
At Plant #837 the tail gases are scrubbed with soda ash
solution, and the resulting solution is sent to an adjacent
facility for use. The water from the wet scrubbers on the
hydrated alumina dryers are also sent to an adjacent facility for
use. The waste waters from area washdown are combined with other
product wastewater, treated with hydrated lime and sent to a
settling lagoon before being discharged.
Plant #188 produces aluminum fluoride in small quantities
and in batches. The waste water from the batch operation is
first sent to a collection pond. It then goes to a second pond
where lime and alum are added and finally, to a third pond where
the pii is adjusted by recarbonation.
Plant #605 mixes the aluminum fluoride waste with
hydrofluoric acid plant waste. The combined waste water is sent
to gypsum ponds for suspended solids removal. The supernatant is
treated with an effluent stream from another plant product for pH
control and neutralization. Because of the presence of complex
fluorides (from the HF process) in the waste waters, the plant is
planning in the near future to use a new proprietary process to
further reduce fluoride levels in the final effluent.
Description of Plants Visited and Sampled
Screening - Plant #705 was visited in the screening phase of
tne program. Both hydrofluoric acid and aluminum fluoride are
336
-------
TABLE 15-6. WASTE WATER FLOW AT PLANTS #837, #705 AND #605
FOR ALUMINUM FLUORIDE SUBCATEGORY
Source
Flow rate per unit of production
m /kkg of A1F-
Scrubber water
Maintenance equipment
cleaning and work area
washdown
Other (Storm water)
Plant #837
3.44
1.13
7.55
Plant #705
9.1
2.39
NA
Plant #605
19.95
1.61
NA
NA = Not Available.
337
-------
produced at this facility by the general processes described
earlier. The waste water from the hydrofluoric acid and aluminum
fluoride plants are mixed and sent to the treatment facility. At
the treatment facility the combined wastewater is neutralized
with lime and sent to a series of settling ponds. The effluent
from the last pond is given a final pH adjustment before a
portion of it is discharged and the rest recycled to the process.
Figure 15-2 shows a simplified block diagram of the process
including the waste water treatment facility and sampling
locations. Table 15-7 presents a summary of flow data of the
sampled streams, and the emissions data for important classical
pollutant parameters.
Plant #705 was visited again and the same streams sampled in
the screening phase were sampled and analyzed in the verification
phase. The variations in individual stream flows were small
during the two phases of sampling. Table 15-7 summarizes the
flow data and important classical pollutant emissions. A second
plant (Plant #605) was visited and sampled in the verification
phase. Simplified flow diagrams of the aluminum fluoride
manufacturing plant and the waste water treatment facility
showing the sampling locations are given in Figure 15-3. Table
15-8 gives the flow of the waste streams and the emissions of
classical pollutants. The aluminum fluoride and hydrofluoric
acid waste streams are combined and sent to a gypsum pond for
suspended solids removal. The overflow from the pond is mixed
with alkaline or acid streams from other plants for
neutralization and pH adjustment before discharge.
Evaluation of Industry Production and Wastewater Flow Data
Figure 15-4 shows the relationship between production and
waste water flow data. The data are taken from 308
Questionnaires, plant visits and development documents.
Different wastes from the aluminum fluoride process are
intermixed before treatment. As mentioned earlier, scrubber
water constitutes the- major source of the waste water stream in
the aluminum fluoride subcategory. If the production of aluminum
fluoride is integrated with hydrofluoric acid, then the waste
waters from both plants are combined and treated.
Solid Waste Generation
In aluminum fluoride production, hydrofluoric gas and
solids, such as aluminum trihydrate and aluminum fluoride, escape
with the vent gases. During scrubbing the solids are suspended
in the scrubber water, while hydrofluoric acid gas is dissolved.
*n the waste water treatment facility the wastewater is
neutralized with lime and the calcium fluoride formed
Precipitates out and settles with the other suspended solids. In
338
-------
WATER
CO
U)
VENT
'AQUEOUS
HF
SCRUBBER]^
WATER
c
$ «3
SCRUBBER
AlF3 PRODUCT -^
REACTOR
^ '
CCXDLER
-Ai(ai).
SURFACE DRAINS
COOLING TOiJER BLOWDOWN, ETC.
SETTLING POND
RECYCLED WATER
FINAL pi I
ADJUS1MENT
TREATED
EFFLUENT
DISCHARGE
Figure 15-2. General process flow diagram at Plant 0705 showing the sampling points.
(Aluminum Fluoride Manufacture)
-------
15-7. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED
WASTE STREAMS FOR PLANT #705 PRODUCING ALUMINUM FLUORIDE
Sampling Sampled Sampled Unit
Phase Stream Stream Flow
No. Description
Unit SS
Load
kg/kkg
of AlF.,
Unit
Fluoride
kg/kkg
of AlF,
Unit
Aluminum
kg/kkg
of A1F0
Screening 3
4*
A1F3 scrubber 8.9 117
Surface drains, 17.8 3.5
cooling tower,
blowdown, etc.
Treated waste 24 1.98
4.67
6.14
1.63
6.94
0.76
0.168
Verifica-
tion
3
4*
AlF.. scrubber
8.9
Surface drains, 17.8
cooling tower,
blowdown, etc.
Treated waste 24
12.8
3.57
0.048
12.32
3.01
0.55
4.08
0.475
0.012
*
This waste is contributed by both the HF and AlF plants
340
-------
VENT
1
VENT
I
WET
SPAR
CO
Al O "3H O
2 3 I 2
A1F,
3
PLANT
REACTOR
WATER ~
i
A1F
SCRUBBER
1
^ S02 SCRUBBER
1
I
£1
M«
WATER
HOSE DOWN VCVTER
AHF PLANT
#2
Vtoste streams sampled.
EFFLUENT TO RIVER
AIJ
-------
T&BLE 15-8. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED' STREAMS
FOR PLANT #605 PRODUCING ALUMINUM FLUORIDE
Stream
No.
4
6
2
3
Sampled
Stream
Description
A1F3 Scrubber Water
SO,, Scrubber Water
Gypsum Pond Influent
Gypsum Pond Effluent
Unit
Flow
m^/kkg
of A1F-
11.86
12.2
24.86
24.8
Unit
Fluoride
Load
kg/kkg
of A1F3
5.53
19.3
16.35
8.00
Unit SS
Load
kg/kkg
of A1F_
j
14.7
2.6
NA
0.232
342
-------
t bUUU
O
^ 50UU
j
<
OA o n n
"i U U U
"3 Hon.
J U U U
^ "> n n n
jS ZU U U
.i
fa
i nnn
^IQUU
|—|
2
!D
l^
^ 1
" -"i
^
5 ?
s£
J
50 100
150
200
PRODUCTION, TPD
1 - Plant #705
2 - Plant #251
3 - "Plant #837
See Reference 2.
Figure 15-4. Production vs. Unit Waste Flow for
Aluminum Fluoride Manufacture.
343
-------
the majority of cases, the solids are retained in the lagoon for
periods up to ten years. Table 15-9 gives a summary of the
amounts of solids generated at two aluminum fluoride plants.
Process Modifications and Technology Transfer Options
1) Total recycle of waste water to the scrubbers is
feasible if final neutralization is with soda ash. The calcium
in the waste is precipitated as calcium carbonate and scaling
problems in pipes and scrubbers are reduced.
2) Passage of the vent gases from the reactor through a
cyclone prior to scrubbing with water will remove the aluminum
oxide and aluminum fluoride particulates. The collected material
in the cyclone can be recycled to the reactor. The installation
of a cyclone will result in material recovery and will also
reduce the suspended solids load going to the waste water
treatment facility.
Best Management Practices
1) Rainfall runoff in plant areas and treatment facilities
and other places susceptible to fluoride contamination can be
collected and sent to the waste water treatment facility.
2) If solid wastes containing fluoride are stored on land,
studies should be conducted to ascertain the risk of
contaminating ground water. Where necessary, provisions can be
made for collection and treatment of leachate, permeate, and
r.unof f .
3) Settling ponds in the waste water treatment facility
should be deep enough (or provided with baffles) to eliminate or
reduce the stirring effect of winds and rainfall. This will
reduce the incidence of weather-related plant upsets, and
suspended solids limitations will be more consistently met.
Model Plant and BPT Treatment System Specifications
waste water flow - The range of waste water data on file
shows flow variations from 11.5 m3/kkg of A1F3 to 21.5 m3/kkg of
Ali'3 (see Table 15-6) . Based on these values, a unit flow of
15.2 m3/kkg of A1F3 was taken as the average for the waste water
treatment model plant for cost estimation.
Production - Six plants manufacture aluminum fluoride at a
total production rate of 120,000 kkg/yr. Individual plant
production rates range from a minimum of 38 kkg/yr to a maximum
of 45600 kxg/yr wi tn a mean of 24,309 and a median of 35,500
344
-------
TABLE 15-9. SOLIDS GENERATED AT PLANT #705 AND #605 PRODUCING
ALUMINUM FLUORIDE
Plant Total Solids Generated kg/kkg of A1P
#705 54
#605 69
345
-------
kKg/yr. For waste water treatment cost estimates, three
production levels were selected as model plants. These three
models reflect the production levels of the plants for which data
is on file (excluding a small batch operation plant) and are
17,500 kkg/yr, 39,200 kkg/yr and 50,400 kkg/yr.
Pollutant loadings - Observed pollutant loadings varied from
14 to 27 kg/kkg of A1F3 for suspended solids and from 5.4 to 39.5
Kg/kkg of A1F3 for fluoride. The data sources are as follows:
Source of Data TSS kg/kkg-AlF3 F kg/kkg-AlF3
EPA Document 1974[Ref] 16-20 15-20
Screening and
Verification
Phase - Plant Data 14-27 5.4-39.5
For model plants pollutant loadings of 20 kg of suspended
solids and 18 kg of fluoride per kkg of A1F3 were used to
establish treatment requirements.
Treatment chemicals - Lime (CaO powder form) is added to
precipitate fluoride and to raise the pH to the range six to
nine. For each of the model plants, lime is added as 25 percent
in excess over the stoichiometric requirements for fluoride
precipitation. For advanced treatment, ferrous sulfide is added
to give a concentration of 10 ppm. This acts as a polishing step
to remove additional trace metals from the effluent. For a more
advanced level of treatment, soda ash is added in addition to
lime (CaO). The soda ash dosage was assumed to be 770 kg/kkg.
Variation _i_n flow and pollution loading - To indicate the
effect on costs of higher and lower pollutant loadings, cost
estimates were developed for one model plant (35,600 kkg-A!F3/yr)
at 27 kg of SS/ kkg-AlF3 and 30 kg fluoride/kkg-AlF3 and 14 kg
fluoride/kkg-AlF3. The waste water flow for these additional
estimates was maintained the same as in the original mode (i.e.,
15 m3/kkg-Alf3) . Unit flows were also varied to monitor the
sensitivity of cost to plant size. In this case, the pollutant
loads were assumed to be the same as in the original model. The
range of flows used were 10.1 m3/kkg to 22.8 m3/kkg.
Generation ojf Solids - From the pollutant loadings and
treatment chemicals above, the waste treatment residue consists
of 20 kg/kkg of suspended solids plus 46.2 kg/kkg from added
chemicals. Thus, the total solids generated are 66.2 kg/kkg of
product. After mechanical removal to self draining piles at
site, the combined fluoride (AsCaF2) is reasonably stable at the
reaction pH reached during lime treatment.
346
-------
15.2 TECHNOLOGY BASED POLLUTION ABATEMENT
15.2.1 Advanced Level Treatment Applications
Control of Significant Observed Priority Pollutants
Tne priority pollutants found in actual plant waste waters
include copper, arsenic, chromium, and selenium. In the case of
selenium, it is apparent that the source was largely the raw
water supply and is therefore not regarded as a process related
pollutant, but the control of selenium in the treated effluent
may be required.
Copper and chromium may be present as trace impurities in
the hydrofluoric acid used to react witn bauxite to form aluminum
fluoride. Arsenic may originate as an impurity in the bauxite
ore. Waste treatment processes should be designed to control
fluoride, copper, arsenic, and chromium.
Removal Technologies Available
Copper and chromium can be precipitated as hydroxides at
alkaline pH levels, and in clarified solutions they may be
exchanged for hydrogen or sodium ions by ion exchange. Copper
and chromium at low levels may also be controlled by xanthate
precipitation, although the process is not widely used. Sulfide
precipitation will reduce copper to very low levels but will not
control chromium or arsenic. Although the mechanism is not
clear, arsenic levels appear to be reduced in the lime
neutralization process followed at most plants, perhaps by
entrapment or adsorption of the oxide during the precipitation of
calcium fluoride. A combination of lime and ferric sulfate
coagulation is probably the most effective practical method for
reducing arsenic concentrations.
Selection of Appropriate Technology
BPT (Level !_)_ - Lime is widely used in the industry_ to
remove the primary nonconventional pollutant as calcium fluoride.
Because lime neutralization to pH 10 results in significant
incidental removal of copper, chromium, and arsenic, alkaline
precipitation was chosen as BPT (Level 1) technology.
Level 2_ - Improved removal of the suspended precipitate is
achieved by dual media filtration.
Level 3_ - Sulfide precipitation is used to attain a higher
level of copper removal.
347
-------
Level 4_ - The technology is similar to Level 2, except that
soda ash is substituted for part of the lime treatment,
permitting partial recycling of effluent.
Flow Diagrams
The facilities to achieve each level of treatment are shown
schematically in the following diagrams:
Level 1 Figure 15-5
Level 2 Figure 15-6
Level 3 Figure 15-7
Level 4 Figure 15-8
Equipment functions Level !_ - This consists of flow
equalization with first stage 1 irne application followed by second
stage lime application and lagoon settling. The final pH is
adjusted with hydrochloric acid to the 6-9 range before discharge
through an effluent monitoring system.
Level 2_ - Dual media filtration is added to provide better
control of suspended solids, including heavy metal hydroxides,
which are returned to the lagoons as filter backwash.
Level 3_ - Ferrous sulfide is prepared on site from ferrous
sulfate and sodium bisulfide and is added ahead of the dual media
filter shown in Level 2, to reduce heavy metals (except chromium)
to lower levels by sulfide precipitation.
Level 4_ - A modification of Level 2 which allows partial
recycling of final effluent by substituting soda ash for part of
the lime treatment, and settling the resulting calcium carbonate
in a clarifier before filtration. This step reduces the calcium
saturation and permits recycling of effluent without serious
scaling problems. Although a small blowdown of effluent is
maintained for control of salinity the total mass discharge of
priority pollutants is less than that achieved in Level 2 due to
the lower effluent flow rate.
Chemicals and handling - In BPT (Level 1) and in Level 2,
two-stage neutralization is accomplished with lime alone, using
conventional handling equipment to deliver milk of lime to two
points of application. In Level 3, a mixture of ferrous sulfate
and sodium bisulfide is prepared in a well-ventilated space and
applied with a conventional solution feeder to the inlet of the
Level 2 dual media filter. With adequate ventilation and proper
PH control in this chemical preparation, there are no unusual
problems in chemical handling. In Level 4, soda ash is used to
348
-------
U)
I
"I
IAGOCN
RAW
WASTE WATER
MIXING
IAQOCN
pH ADJUSTMENT
~ T
EFFUUENT
•Includes flow monltDring, pH monitoring and sampler.
Figure 1-5-5. Waste water treatment Level 1 for aluminum fluoride subcategory.
-------
BACKWASH
CO
o
^-^
RAW
WASTE
LIME
1
WATER
c
/
_t^ /»,
EQUALIZATION
I--'©
1
1
1
1
>b
.^^^, •_»
r
1 , ^>v LAGOON ^^1
J? i
-*J -•-*•
MIXING ^ ^
L'
. ]
1
/
"-•*•
^
i
IwT-' ^
f
MpH ADJUSTME2^r
X ; ^,
/ \ 1' 1 ^
•^
FiL'ilSK * j
EFFLUENT
*Includes flow monitoring, pH monitoring and sanpler.
Figure 15-6. Waste vater treatment Level 2 for alvminum fluoride subcategory.
-------
LIME
U*£>-|
U)
Ln
RAW
WASTE WATER
EQUAIIZATION
•Q-^
FERROUS SULFATE
SODIUM BISULFIDE
r
1
ii
i!
NUXING
BACKWASH
LAGOON
LAGOON
Includes flov/ monitoring, pH iTionitoring and sampler
pH
ADJUSTMENT
r—Q-
SUMP
T
FILTER
'EFFLUENT
Figure 15-7. Haste water treatment Level 3 for aluminum fluoride subcabegory.
-------
U)
Ul
NJ
WASTE
WATER
EFFLUENT
Includes flow monitoring, pll monitoring and Bampler
Figure 15-8. HaBbawatcr trcatnunl Level 4 far aluminum fluoride Bubcalegory
-------
furnish part of the alkalinity, employing conventional dry
chemical feeding equipment for this non-hazardous chemical.
Separation and removal of solids - At all levels of
treatment the precipitated solids are removed mechanically from
the lagoons at regular intervals and are piled in self-draining
areas near the lagoons, on land provided for a ten-year operating
period. Fluoride and priority pollutants are in the insoluble or
adsorbed form and do not constitute a hazard to the local
environment when left at the plant site under controlled
conditions, i.e., with leachate and permeate control.
Monitoring requirements - Control of fluoride and priority
pollutants in the treatment process can be reasonably assured by
pH and fluoride ion field testing equipment. At advanced levels
very low values of toxic metals and arsenic are best detected by
atomic absorption methods, normally performed in commercial
laboratories on carefully collected and composited samples.
15.2.2 Estimated Performance o_f BPT Systems
Raw waste pollutant loads found in the aluminum fluoride
subcategory were presented earlier. The major pollutants
previously regulated are suspended solids, fluoride and aluminum.
The priority pollutants that were found in quantities that
might require control and regulation are selenium and copper.
BPT has been identified as lime precipitation of fluorides
followed by settling to remove suspended solids.
Base Level Performance Characteristics for BPT Pollutant Removal
The three major manufacturers of aluminum fluoride also
produce hydrofluoric acid at the same facility. Two of the
plants treat both sources of waste water together; the third
uses the aluminum fluoride wastes in other proceses.
Consequently, no data are available for the separate treatment of
aluminum fluoride waste water. However, it can be assumed that
the effluent quality achievable will be at least equivalent to
that of the hydrofluoric acid subcategory since BPT technology is
the same for the two subcategories.
Table 15-10 presents effluent quality achievable through the
implementation of BPT or Level 1 technology for aluminum fluoride
plants.
353
-------
TABLE 15-10 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Aluminum Fluoride
Level of Treatment: 1
Waste Water Flow: 15.2 m3/kkg
Quality Limit Emission Limit
Subcategory (1) (mg/1) (kg/kkg)
Pollutant Performance VFR
(mg/1) 30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants:
Total Suspended
Solids, TSS
(2)
2.0
37.5
75
0.57 1.1
(2)
Aluminum, Al -
(2)
Fluoride, F
Proposed Priority
Pollutants
(2)
Copper, Cu
(2)
Selenium, Se
3.0 4.0 12 0.06 0.18
3.0 37.5 112 0.57 1.7
2.0 0.5 1.0 0. 008 0. 015
2.0 0.2 0.4 0.003 0.006
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Specific plant performance data is available only for
the combined treatment of HF and A1F3 process wastes.
354
-------
Base Level (BPT) Performance Characteristics for Priority
Pollutant Removal
Pretreatment Applications
No aluminum fluoride manufacturing facilities are known to
discharge to a POTW. BPT technology will be applicable, however,
should such a discharge occur in the future.
Response to Remand Issues
Industry's arguments regarding the regulation of
hydrofluoric acid and aluminum fluoride waste discharges have
primarily centered on tne treatability of fluorides. Complex
fluorides not amenable to treatment do occur in hydrofluoric acid
drip acid waste. However, no complex fluorides are known to
occur in aluminum fluoride waste waters.
Industry also recommended that the two subcategories be
combined or that a third subcategory be established for
facilities where hydrofluoric acid and aluminum fluoride are both
manufactured. This subject is discussed in Section 4 dealing
with subcategorizations.
15.2.3 Estimated Performance of Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
Implementation of advanced level treatment alternatives are
estimates to achieve the effluent quality presented in Table
15-11, 15-12, and 15-13.
New Source Applications-
Examination of waste water control and treatment
alternatives applicable to new facilities for the production of
aluminum fluoride has led to the conclusion that the technology
applicable to NSPS is 80 percent recycle of treated waste waters
to air pollution control scrubbers, identified as Level 4. This
technology exists in the hydrofluoric Acid Subcategory.
355
-------
TABLE 15-11 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Aluminum Fluoride
Level of Treatment: 2
Waste Water Flow: 15.2 m3/kkg
Quality Limit Emission Limit
(1) (mg/1) (kg/kkg)
Pollutant Treatability VFR
(mg/1) 30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants:
Total Suspended 15 2.0 15 30 0.23 0.46
Solids, TSS
Aluminum
Fluoride
Proposed
, Al
, F
Priority
4.0
25
3.
3.
0
0
4.0
25
12
75
0.
0.
06
38
0.
1.
18
1
Pollutants
Copper ,
Selenium
Cu
, Se
0.1
0.1
2.
2.
0
0
0. 1
0.1
0. 2
0.2
0.
0.
0015
0015
0.
0.
003
003
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
356
-------
TABLE 15-12 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Aluminum Fluoride
Level of Treatment: 3
Waste Water Flow: 15.2 m3/kkg
Pollutant
Treatability
(mg/1)
(1)
VFR
Quality Limit
(mg/1)
Emission Limit
(kg/kkg)
30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants;
Total Suspended
Solids, TSS
15
2.0
15
30
0.23
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
0.46
Al urn in urn
Fluoride
Proposed
Pollutan
Copper ,
Selenium
, Al
, F
Prior ity
ts
Cu
, Se
4.0
25
0.05
0.1
3.
3.
2.
2.
0
0
0
0
4.0
25
0.05
0.1
12
75
0.1
0.2
0.
0.
0.
0.
06
38
0008
0015
0
1
0
0
.18
.1
.0015
.003
357
-------
TABLE 15-13 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Aluminum Fluoride
Level of Treatment: 4
Waste Water Flow: 3 m3/kkg (80% Recycle)
Pollutant Treatability
(mg/1)
BPT Pollutants:
Total Suspended 15
Solids, TSS
Aluminum , Al 4.0
Fluoride, F 25
Proposed Priority
Pollutants
Copper, Cu 0.1
Selenium, Se 0.1
Quality Limit
(1) (mg/1)
VPP —
30 day 24 hr
Av e r Ma x
2.0 15 30
3.0 4.0 12
3.0 25 75
2.0 0.1 0.2
2.0 0.1 0.2
Emission Limit
(kg/kkg)
30 day
Aver
0.045 0
0.012 0
0.075 0
0.0003 0
0.0003 0
24 hr
Max
.09
.036
. 15
.0006
.0006
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
358
-------
15.2.4 Cost Estimates
General Discussion
The estimated costs for models having three different
production and four levels of treatment are given in Tables
15-14, 15-15 and 15-15. For these models, both the hydraulic and
pollution loads per unit of production are held constant over the
entire range of production. Annual treatment cost as a function
of production is shown graphically in Figure 15-9. Similarly,
treatment cost per metric ton of product is given in Figure
15-10.
To indicate the effects on cost of varying the pollutant
load per unit of product, cost estimates were developed for one
medium size production model plant at higher solids and pollutant
(fluoride) loadings. For these models the hydraulic load per
unit of production was held constant. The cost -estimates for
these models are given in Tables 15-17 and 15-18. The effects on
costs of varying the unit pollutant load are shown graphically in
Figures 15-11 and 15-12 at Levels 1 and 4. Variation of
pollutant loads has a significant impact on Level 1, but had no
effect on the incremental costs of treatment at levels 2 and 3
which are not shown.
To judge the effects on cost of varying the hydraulic load
per unit of production, cost estimates were developed for one
medium size production model plant at a higher and a lower
hydraulic loadings. The pollutant load per unit of production
was held constant for these models. Tables 15-19 and 15-20 show
the cost estimates. At treatment Levels 2, 3 and 4 the effects
on costs of varying the per unit hydraulic load are shown
graphically in Figures 15-13, 15-14, and 15-15. Hydraulic load
variation had no significant effect on the costs of treatment at
Level 1. Table 15-21 presents a summary of the unit cost
distribution between amortization and the operation and
maintenance cost components at various production and levels of
treatment. The effects on cost due to variations in unit
pollutant and hydraulic loads are also shown in Table 15-21.
Summary
At the first level of treatment, chemicals, labor, and
amortization have significant impact on the annual costs. At
second, third and fourth levels of treatment, the operation and
maintenance cost comprises of approximately two-thirds of the
additional annual costs, and the remaining one-third is due to
amortization.
359
-------
TABLE 15-14 MOEEL PLANT TREATMENT COSTS
Subcategory ALUMINUM FLUORIDE
Production
Type of Regulation BAT
15,900 metric tons per year ( 17,529 tons per year)
45 metric tons per day ( 50 tons per day )
Waste water flow 690 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, contingencies...
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Maintenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
LEVEL OF TREATMENT*
FIRST SECOND THIRD FOURTH
$39,800 $10,000 $14,000 $20,500
192,000
9,000
48,160
48,160
24,000
68,000
15,600
15,600
74,000 172,000
17,600
17,600
38,500
38,500
$361,120 $109,200 $123,200 $269,500
$56,000
3,400
35,000
33,712
10,833
5,400
15,000
$159,345
$54,849
$14,000
600
10,920
3,276
7,500
$36,296
$17,766
$14,000
900
800
12,320
3,696
7,500
$39,216
$20,044
$14,000
2,500
9,800
26,950
8,085
7,500
$68,835
$43,847
$214,194
$54,062 $59,260 $112,682
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
360
-------
TABLE 15-15. MOEEL PLANT TREATMENT COSTS
Subcategory ALUMINUM FLUORIDE
Production
Type of Regulation BAT
35,600 metric tons per year ( 39,249 tons per year)
101 metric tons per day ( 112 tons per day )
Waste water flow 1550 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, contingencies...
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Maintenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
LEVEL OF TREATMENT*
FIRST SECOND THIRD FOURTH
$63,600 $15,000 $19,000 $34,000
238,000
9,000
62,120
62,120
42,000
84,000
19,800
19,800
90,500 259,000
21,900 58,600
21,900 58,600
$476,840 $138,600 $153,300 $410,200
$56,000
5,500
80,000
43,484
14,305
12,500
15,000
$14,000
900
13,860
4,158
7,500
$14,000
1,300
1,800
15,330
4,599
7,500
$14,000
3,100
18,800
41,020
12,306
7,500
$226,789 $40,418 $44,529 $96,726
$70,748 $22,550 $24,941 $66,739
$297,537 $62,968 $69,470 $163,465
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
361
-------
TABLE 15-16. MODEL PLANT TREATMENT COSTS
Subcategory ALUMINUM FLUORIDE Type of Ftegulation BAT
Production 45,800 metric tons per year ( 50,494 tons per year)
130 metric tons per day ( 144 tons per day )
Waste water flow 1990 cubic meters per day.
A. INVESTMENT COST
Equipment in place,
including piping,
fittings, electrical
Monitoring equipment
Engineering design
Incidentals, overhead,
fees, contingencies...
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Ma intenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
FIRST
$76,500
281,000
9,000
73,300
73,300
60,000
$573,100
$56,000
7,400
100,000
51,310
17,193
16,000
15,000
$262,903
$83,481
$346,384
LEVEL OF
SECOND
$20,500
110,000
26,100
26,100
$182,700
$14,000
1,500
18,270
5,481
7,500
$46,751
$29,725
$76,476
TREATMENT*
THIRD
$24,500
116,500
28,200
28,200
$197,400
$14,000
1,900
2,400
19,740
5,922
7,500
$51,462
$32,116
$83,578
FOURTH
$43,000
317,000
72,000
72,000
$504,000
$14,000
4,300
26,400
50,400
15,120
7,500
$117,720
$82,000
$199,720
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
362
-------
500
O
O
O
rH
X
U
400
300
ZOO
100
!
1
|
1
i
i
i
1
j
i
i
i
i
i
l
i
i
i
i
,
1
!
^
^—7
_ j^
i
_J-**
V^
1
I
!
i ; '
} [
i !
i
L/T
x
/
X
^^
X
•""""
^*-
!
1 1
x
! i
i
!
|
J® LE
~S^
i
r
•r'T ' • :
xiV
1
f?
^-T ""
i
^
^
-J®T^
-^[
|
l
1
1
i
i
i i
!
^
^ Lz
-^
j® M
^ \
i
j
\
\ \
\
\
i i
\
l
i
VEL #4
j
i
VELS *2 &
-
VELJ |ffl
i
' j
i i . '
i i
1
i
1
3
!
1
i
l
1
1
i
10 20 30 40 50
PRODUCTION, METRIC TONS/YEAR X 1000
Figure' 15-9. Annual treatment cost vs. production for the
Aluminum Fluoride Subcategory
363
-------
20
±
15
•en-
JO.
10
ii #k i
j i
i _j iLEVEE ^
j i
VELi
! I
i i
i i
10 20 30 40 50
PRODUCTION, METRIC TON/YEAR X 1000
Figure 15-10. Annual unit treatment cost vs. production for the
Aluminum Fluoride Subcategory
364
-------
TABLE 15-17. MODEL PLANT TREATMENT COSTS
Subcategory ALUMINUM FLUORIDE
Production
Type of Regulation BAT
35,600 metric tons per year ( 39,249 tons per year)
101 metric tons per day ( 112 tons per day )
Waste water flow 1550 cubic meters per day.
A. INVESTMENT COST
B.
LEVEL OF TREATMENT*
FIRST SECOND THIRD FOURTH
Equipment in place,
including piping,
fittings, electrical
Monitoring equipment
Engineering design
Incidentals, overhead,
fees, contingencies —
TOTAL INVESTMENT COST
OPERATION AND
MAINTENANCE COST
Labor and supervision.
Enerqy
Chem icals
Taxes and insurance...
Residual vvaste
disposal
Monitoring, analysis
TOTAL OPERATION AND
MAINTENANCE COST
AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$82,000
241,000
9,000
66,400
66,400
66,000
$530,800
$56,000
5,500
130,000
46,480
15,924
19,000
15,000
$287,904
$75,622
$363,526
$15,000
84,000
19,800
'19,800
$138,600
$14,000
900
13,860
4,158
7,500
$40,418
$22,550
$62,968
$19,000
90,500
21,900
21,900
$153,300
$14,000
1,300
1,800
15,330
4,599
7,500
$44,529
$24,941
$69,470
$34,500
270,000
60,900
60,900
$426,300
$14,000
3,100
31,500
42,630
12,789
7,500
$111,519
$69,359
$180,878
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
365
-------
TABLE 15-18. MOEEL PLANT TREATMENT COSTS
Subcategory ALUMINUM FLUORIDE
Prediction
Type of Regulation BAT
35,600 metric tons per year ( 39,249 tons per year)
101 metric tons per day ( 112 tons per day )
Waste water flow 1550 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND THIRD FOURTH
A. INVESTMENT COST
Equipment in place,
including piping,
fittings, electrical
work and controls .....
Monitoring equipment
Engineering design
Inc identals , overhead ,
fees , contingenc ies . . .
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Maintenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$56,900
221,000
9,000
57,380
57,380
30,000
$431,660
$56,000
5,500
60,000
40,166
12,949
9,000
15,000
$198,615
$65,350
$263,965
$15,000
84,000
19,800
19,800
$138,600
$14,000
900
13,860
4,158
7,500
$40,418
$22,550
$62,968
$19,000
90,500
21,900
21,900
$153,300
$14,000
1,300
1,800
15,330
4,599
7,500
$44,529
$24,941
$69,470
$34,000
259,000
58,600
58,600
$410,200
$14,000
3,100
14,610
41,020
12,306
7,500
$92,536
$66,739
$159,275
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
366
-------
20
15
1 I I
3
£L'jn
T/
10
\\
M
7-
^gsn POTJ.TITO
TO 20 TO «50"
A1F3 PRODUCTION, METRIC IONS/YEAR X 1000
60
Figure 15-11. Effect of variation of pollutant load on treatment
cost at level 1 technology
367
-------
20
JsL
Tb POTJJTTMITl LOAD
I I
15
O
s
I S.
ZL
10
rn/rT
I I
y-
i i i
D I I
i
10
20
30
40
50
60
A1F3 PRODUCTION, METRIC TONS/YEAR X 1000
Figure 15-12. Effect of variation of pollutant load, on treatment
cost at level 4 technology
368
-------
TABLE 15-19. MODEL PLANT TREATMENT COSTS
Subcategory ALUMINUM FLUORIDE
Production
Type of Regulation BAT
35,600 metric tons per year ( 39,249 tons per year)
101 metric tons per day ( 112 tons per day )
Waste water flow 2203 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND THIRD FOURTH
A. INVESTMENT COST
B.
Equipment in place,
including piping,
fittings, electrical
Monitoring equipment
Engineering design
Incidentals, overhead,
fees, contingencies...
TOTAL INVESTMENT COST
OPERATION AND
MAINTENANCE COST
Labor and supervision.
Enerqy
Chemicals
Taxes and insurance . . .
Residual waste
d isposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$66,100
256,000
9,000
66,220
66,220
42,000
$505,540
$56,000
7,400
80,000
46,354
15,166
12,500
15,000
$232,420
$75,417
$307,837
$21,000
117,600
27,720
27,720
$194,040
$14,000
1,500
19,404
5,821
7,500
$48,225
$31,570
$79,795
$25,000
124,000
29,800
29,800
$208,600
$14,000
1,900
1,800
20,860
6,258
7,500
$52,318
$33,939
$86,257
$43,500
321,000
72,900
72,900
$510,300
$14,000
4,700
18,800
51,030
15,309
7,500
$111,339
$83,025
$194,364
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
369
-------
TABLE 15-20. MOEEL PLANT TREATMENT COSTS
Subcategory ALUMINUM FLUORIDE Type of Regulation BAT
Prediction 35,600 metric tons per year ( 39,249 tons per year)
101 metric tons per day ( 112 tons per day )
Waste water flow 1064 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND THIRD FOURTH
A. INVESTMENT COST
Construction $63,600 $14,500 $18,500 $30,000
Equipment in place,
including piping,
fittings, electrical
vvork and controls 237,000 70,300 76,000 206,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 61,920 16,960 18,900 47,200
Incidentals, overhead,
fees, contingencies... 61,920 16,960 18,900 47,200
Land... 42,000
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Maintenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
$475,440 $118,720 $132,300 $330,400
$56,000
5,500
80,000
43,344
14,263
12,500
15,000
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$226,607
$70,520
$297,127
$14,000
600
11,872
3,561
7,500
$37,533
$19,315
$56,848
$14,000
900
1,800
13,230
3,969
7,500
$41,399
$21,525
$62,924
$14,000
2,500
18,800
33,040
9,912
7,500
$85,752
$53,756
$139,508
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
370
-------
20-
I ! ! !
i i
o
u
\i\
y
^IQREASED
5YDRAHJLIC
v
A
s
I'Cv
A
£4.
LQMD
I i
I I
10
Figure 15-13
20 30 40 50 60
3 PRODUCTION, METRIC TONS/YEAR X 1000
Effect of variation of hydraulic load on treatment
cost at level 2 technology
371
-------
20
TT
u
15
8
u
10
f
\i\T i
t:
N,
, I
I ' !
I
10 20 """ 30 40 50 60
A1F3 PRODUC1TCN, METRIC TONS/YEAR X 1000
Figure 15-14. Effect of variation of hydraulic load on treatment
cost at level 3 technology
372
-------
20
U
15
u
10
i i
\l
_L
. I i
i I
10 20 30 40 50 60
A1F3 PRODUCTION, METRIC TONS/YEAR X 1000
Figure 15-15. Effect of variation of hydraulic load on treatment
cost at level 4 technology
373
-------
TABLE 15-21 MODEL PLANT TREATMENT COSTS
Subcategory ALUMINUM FLUORIDE
Type of Regulation BAT
Annual Treatment Costs/Metric ton of Product
Annual Operation
and Maintenance
Annual
Anortization
Total Cost
PRODUCTI01
(kkg/yr)
15,900
35,600
45,800
a 35,600
b 35,600
c 35,600
d 35,600
15,900
35,600
45,800
a 35,600
b 35,600
c 35,600
d 35,600
15,900
35,600
45,800
a 35,600
b 35,600
c 35,600
d 35,600
!J FLOW
(ni3/day)
690
1,550
1,990
1,550
1,550
2,203
1,064
690
1,550
1,990
1,550
1,550
2,203
1,064
690
1,550
1,990
1,550
1,550
2,203
1,064
FIRST
$
10.02
6.37
5.74
8.09
5.58
6.53
6.37
3.45
1.99
1.82
2.12
1.84
2.12
1.98
13.47
8.36
7.56
10.21
7.41
8.65
8.35
LEVEL OF T
SECOND
$
2.28
1.14
1.02
1.14
1.14
1.35
1.05
1.12
0.63
0.65
0.63
0.63
0.89
0.54
3.40
1.77
1.67
1.77
1.77
2.24
1.60
IEATMEN
THIRD
$
2.47
1.25
1.12
1.25
1.25
1.47
1.16
1.26
0.70
0.70
0.70
0.70
0.95
0.60
3.73
1.95
1.82
1.95
1.95
2.42
1.77
T
FOURTH
$
4.33
2.72
2.57
3.13
2.60
3.13
2.41
2.76
1.87
1.79
1.95
1.87
2.33
1.51
7.09
4.59
4.36
5.08
4.47
5.46
3.92
a Increased pollutant load
b Decreased pollutant load
c Increased hydraulic load
d Decreased hydraulic load
374
-------
Effects on annual costs due to higher and lower pollutant
loads per unit of product for a medium level of production model
plant were studied. At high pollutant loading, the annual cost
at the first and fourth levels of treatment increased
approximately by 25 and 35 percent respectively over the base
case cost. At the second and third levels of treatment, annual
costs per unit of product are the same as for the original model.
At lower pollutant loading, annual cost at first level of
treatment decreased by 15 percent below the base case cost. At
other levels, annual costs per unit of product are the same as
for the original model.
Effects of annual costs due to higher and lower hydraulic
load per unit of product for a medium level of production model
indicated that at first level of treatment variation of hydraulic
loads had an insignificant impact on annual cost compared to the
original model annual cost.
In the second, third and fourth levels of treatment, at a
higher hydraulic load, additional annual costs per unit of
production increased by 24, 21, and 18 percent respectively over
the original model costs.
At a lower hydraulic load, additional annual costs per unit
of production decreased by 10 percent at second and third levels,
and by 16 percent at the fourth level, compared to the original
model cost.
375
-------
SECTION 16
CHROME PIGMENTS INDUSTRY
16.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
16.1.1 Industry Profile and Analytical Results
Chrome pigments are mostly sold in the merchant market, and
consequently captive use is very low. They are extensively used
in paints, printing ink, floor covering products and paper. They
are also used in ceramics, cement, and asphalt roofing.
The industrial profile data for this subcategory is given in
Table 16-1, while the existing regulations are in 16-2.
The priority pollutants found at significant concentrations
in the raw waste during sampling at chrome pigments plants (209)
were as follows:
Pollutant
Maximum Concentration
Screening
(ug/1)
Verification
(2 Plants)
Cadmium- 79
Cyanide 360
Chromium 55000-
Copper 7500
Lead 36000
Zinc 4100
Antimony 7700
Selenium <10
Silver 7
Nickel 160
Phenol* 73
Bis (2 ethylhexyl)
Phthalate* <0.1
* from organic pigment process
1,250
8,200
349,000
4,700
69,000
273,000
1,475
28
20
740
A summary
plants sampled
waste loads
of daily and unit product raw waste loads for all
can be found in Table 16-3. Individual plant raw
per unit product found in sampling can be found in
376
-------
TABLE 16-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
CHROME PIGMENTS
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
63,000 kkg/year
64,500 kkg/year
11
4
19,660 kkg/year
30 percent
3,500 kkg/year
8,800 kkg/year
6,300 kkg/year
6,400 kkg/year
78 percent
38 years
60 years
360 cubic meters/day
800 cubic meters/day
32 cubic meters/kkg
60 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
377
-------
TABLE 16-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
Chrome Pigments
SUBPAET AH (40CFR 415.340, 5/22/75)
' " STANDARDS
Product
Process
Chrome
Pigment
BPCTCA* BATEA
1 2
Max. Avg. Max. Avg.
Para- kg/kkg k/kkg k/kkg k/kkg
meters (mg/1) (mg/1) (mg/1) (mg/1)
TSS 5'1
lbb (76.1)*
Cr(T) °-10
^ U} (1.5)
p +6 0.010
^ (0.2)
Pb °'42
(6.3)
Zn °'72
Zn (10.8)
CN °-010
(1.5)
0.10
^J.N V**/ / /\ o \
(0.2)
Fe °'72
(10.8)
1.7
(25.4)
0.034
(0.5)
0.0034
(0.1)
0.14
(2.1)
0.27
(4.0)
0.0034
(0.5)
0.034
(0.1)
0.27
(4.0)
NSPS
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
Sections 415.340, 415.341, and 415.342 were revoked by the Agency
HI FR 51601, November 23, 19761.
Max, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
* flow basis 67,000 1/kkg.
378
-------
TABLE 16-3. SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
U)
^4
SUBCATEGORY
Pollutant
Priority
Antimony, Sb
Cadmium, Cd
Chromium, Cr
Copper, Cu
Lead, Pb
Nickel, Ni
Zinc , Zn
Cyanide, CN
Organic s
Phenols
Phenolics
Conventional
TSS
Iron, Fe
CHROME PIGMENTS
Loadings
kg/day
Minimum Average Maximum Minimum
5.90 51.7 98.0 0.14
0.87 5.44 10.0 0.02
698 1016 1333 11.5
6.08 50.8 95.2 0.14
237 347 458 5.46
1.38 1.71 2.03 0.032
52.2 381 712 0.86
3.11 24.4 45.8 0.072
0.93
8.80
3049
7.03
kg/kkg
Average
0.87
0.16
21.5
0.86
6.49
0.0325
8.63
0.41
0.015
0.14
70.4
O.16
No. of Plants
Maximum Averaged
1.61 2
0.09 2
30.8 2
1.58 2
7.62 2
0.033 2
16.4 2
0.75 2
-------
Table 16-4.
Based on the total annual production and the average waste
load generated per unit product, the estimated total priority
pollutant raw waste loads generated each year for this
subcategory
are as follows
Pollutant
Waste Load (kg/year)
Cadimurn
Chromium
Copper
Lead
Zinc
Antimony
Nickel
Cyanide
10000
1400000
55000
420000
560000
56000
2100
26000
16.1.2 Process Waste Sources and Waste Water Treatment Data
General Process Description
Chrome pigments are a family of inorganic compounds
containing chromium, lead, iron, molybdenum, and zinc used for
pigments. They include chrome yellow, chrome orange, molybdate
chrome orange, anhydrous and hydrous chromium oxide, zinc yellow
and iron blues. At some plants the compounds are made in the same
facility either simultaneously or sequentially depending on sales
and market requirements. The general manufacturing process for
each of the compounds is given below.
Chromium oxide - This pigment consists of two compounds,
anhydrous and hydrated chrome oxide (Guigets Green) . The amount
of the anhydrous salt oxide produced is approximately ten times
the amount of hydrated chromic produced. It is offered in a
narrow range of shades from light yellowish to dark bluish green.
Anhydrous oxide is almost 'pure chromium oxide and the
commercial grade consists of a minimum of 98.5 percent Cr203. It
is prepared by calcination of sodium dichromate with sulfur or
carbon according to the reactions given below:
Na2Cr207 + S = Cr203 + Na2S04 (1)
Na2Cr207 + 2C = Cr203 + Na2C03 + CO (2)
The use of sulfur as the reducing agent eliminates C02, CO
380
-------
TABLE 16-4. PRIORITY POLLUTANT RAW WASTE LOADS (in kg/kkg of Product)
SUBCATEGORY
POLLUTANT
Cyanide, Cn
Chromium, Cr
Cadmium, Cd
Copper, Cu
Lead, Pb
Zinc, An
Antimony, Sb
Nickel, Ni
Phenols
Phenolics
CHROME PIGMENTS
PLANT
#894
0.754
11.5
0.165
1.58
7.52
0.855
1.612
0.0334
0.0152
0.1448
#002
0.072
0.020
30.8
0.140
5.46
16.4
0.136
0.032
No data
No data
381
-------
and S02 emissions but increases the sulfate raw waste. In the
manufacturing process using sulfur, the raw materials consisting
of sodium dichromate and sulfur are mixed with water and the
resultant solution is fed to a Kiln. The material is heated and
the reacted materials from the kiln are slurried with water,
filtered, washed, dried, ground, screened, and packaged. The
effluent gases from the kiln containing sulfur dioxide and sulfur
trioxide are wet scrubbed before venting to the atmosphere.
A general process flow diagram of the preparation of
anhydrous chrome oxide is given in Figure 16-1.
Hydrated chromium oxide, Cr203 2H20 or Cr20(OH)4, also known
as chromium hydrate and Guignets Green, is a brilliant bluish
green. It is made by reacting sodium dichromate with boric acid
as follows:
2Ma2Cr207 + 8H3B03 = 2Cr203.2H20 + 2Na2B407 + 8H20 + 302 (3)
The raw materials are blended in a mixer and then heated in
an oven at about 550 degrees C. The reacted material is slurried
with water and filtered. The filtered solids are washed with
water, dried, ground, screened, and packaged. The filtrate and
the wash water are treated with sulfuric acid to recover boric
acid according to the reaction given below:
Na2B407 + H2S04 + 5H20 = 4H3B03 + Na2S04 (4)
A waste stream containing some boric acid and sodium sulfate
leaves the boric acid unit. Figure 16-2 is a generalized flow
diagram of the process.
Chrome yellow and chrome orange - Chrome yellow is one of
the more important synthetic pigments. The chrome yellows cover
the range of hues from light greenish yellow to reddish medium
yellow and consist mainly of lead chromate. They are made by
reacting sodium dichromate, caustic soda, and lead nitrate. The
reactions are given as:
2HN03 + PbO = Pb(N03)2 + H20 (5)
Na2Cr207 + 2NaOH + 2Pb(N03)2 = 2PbCr04 + 4NaN03 + H20 (6)
Lead chromate is formed as a precipitate during the
reaction. it is filtered and treated with chemicals for
development of desired specific pigment properties, dried,
milled, and packaged. The filtrate from the filtration operation
is sent to the waste water treatment facility. A flow diagram of
the chrome yellow manufacturing process is shown in Figure 16-3.
Molybdenum orange - Molybdenum orange is made by the
coprecipitation of lead chromate (PbCr04) and lead molybdate
382
-------
VENT
U>
OO
I
or
SCRUBBER >»
LICSJUD SCRl
WATER
SnnllJM DTCHRTMATE W
Of,
SULFUR »^
}2
BBER 1
JL
WA.TER WATER
1 1
Tj.] SLURRY FILTER DRYER ^
PACKAGIMG OF
1 CHROME OXIDE
¥ PRODUCT
WASH WATER
Figure 16-1, General process diagram for production of anhydrous chrome oxide.
-------
SOD
DICHR
BORIC ACID
U>
CO
IUM
:MATE
MIXER
VENT
* WATER WATER
t * r
OVEN
SU
SLURRY
.jj^ F.U.TBK UH^EK
KFU1UC ACID
*
BORIC ACID |f
UNIT
QIRDME
OXIDE TO GRINDING,
SCREENING AND
PACKAGING
WASTE WATER
Figure 16-2. General process diagram for production of hydrated chromic oxide.
-------
LEAD OXIDE
WATER
NITRIC ACID
DISSOLVING
LO
CO
WATER
SODIUM DICHKOMZVTE _
, ,_ ., p*
DISSOLVING
to-k
*»^
REACTION
TANK
^
f
FILTRATION
AND
WASHING
1
CHROME YELLOW
(PbCr04)
TO DRYING, MILLING
AND PACKAGING
WASTE WATER
Figure 16-3. General process diagram for production of chrome-yellow.
-------
(FbMo04)
oranges.
The resulting pigments are more brilliant than chrome
The process consists of dissolving molybdic oxide in aqueous
sodium hydroxide and adding sodium chromate. The solution is
mixed and reacted with a solution of lead nitrate. The
precipitate from the reaction is filtered, washed, dried, milled
and packaged. The filtrate, is sent to the treatment facility.
The reactions can be given as follows:
Mo03 + 2NaOH = Na2Wo04 + H20
(7)
PbO + 2HN03 = Pb(N03)2 + H20 (8)
Na2Mo04 + Pb(N03)2 = PbMo04 + 2 NaN03 (9)
Na2Cr04 + Pb(N03)2 = PbCr04 + 2NaN03
PbMo04
PbCr04 = PbCr04. PbMo04
(10)
(11)
A simplified flow diagram for the manufacture of
orange is given in Figure 16-4.
molybdenum
Chrome green - Chrome greens are a coprecipi tate of chrome
iron blues. They include a wide variety of hues from
very dark green. Iron blues are manufactured by
of iron sulfate and ammonium sulfate
is
yellow and
very light to very dark
reaction of aqueous. solution
with sodium hexacyanof errate. The precipitate formed
separated and oxidized with sodium chlorate or sodium chromate to
form iron blues (Fe (NH4) [Fe (CN) 6] . Chrome green is produced by
mechanically mixing chrome yellow and iron blue pigments in
water. The coprecipi tate formation of chrome green is given by:
PbCr04 + Fe(NH4) [Fe(CN)6] = PbCr04Fe (NH4 ) [Fe (CN) 6] (12)
Figure 16-5 gives a
of chrome green.
process flow diagram for the manufacture
Zinc yellow - Zinc yellow, also called zinc chromate, is a
greenish yellow pigment. It is a complex compound of zinc,
potassium, and chromium which has the approximate composition
4ZnO.K20.4Cr03.3H20. It is made by the reaction of zinc oxide,
hydrochloric acid, sodium dichroinate, and potassium chloride.
Zinc yellow is formed as a precipitate and is filtered, washed,
dried, milled, and packaged for sale. The reactions are given
as:
2KC1 + 2HC1 + 2Na2Cr207.H20 = K2Cr4013 + 4NaCl + 3H20 (13)
4ZnO + K2Cr4013 + 3H20 = 4ZnO.K20.4Cr03.3H20 (14)
A general flow diagram of the manufacturing process is given
386
-------
CO
MOLYBDIC OXIDE
WATER
CAUSTIC SODA
*•
LEAD OXIDE
NITRIC ACID
SODIUM
CllROMATE WATER
DISSOLVER
VENT
DISSOLVER
4
PRODUCT
Figure 16-4. General process diagram for production of nolybdate orange.
-------
WATER
IRON BLUE
WAT
LEAD NITRATE ^. ,
U)
?B SODIUM CHROMATE ._
SODIUM SULFATE ..
REACTION
p»
W \
FILTER
AND
WASH
1
SHADE
TANK
DRYER
V
B» GRINDING
BLENDING
AND
PACKING
CHROME GREEN
PRODUCT
WASTE WATER
WASTE WATER
Figure 16-5. General process diagram for production of chrome green.
-------
in Figure 16-6.
Water Use and Waste Source Inventories
Water uses - In the chrome pigment industry water is used
for noncontact cooling, washing the precipitated product, and as
boiler feed for steam generation. In some cases water is
introduced into the reactor along with the raw materials.
In anhydrous and hydrated chrome oxide manufacture, water is
used for slurrying of the reaction product and in scrubbing the
reactor vent gases. Table 16-5 is a summary of water usage at
different pigment plants in the chrome pigments subcategory.
WaSte sources -
some
products sequentially in the
different pigment products are manufactured
waste waters combined and treated at a
generalized flow diagram applicable to all
is given in Figure 16-7. The waste water
for all pigment products except that at
additional scrubber waste is generated.
plants produce different pigment
same process. At a few plants the
concurrently and the
single facility. A
chrome pigment plants
sources are similar
chrome oxide plants an
Table
16-6 gives the
waste water flow data summary for several plants. The quantity of
waste water and the pollutants vary for the different pigment
products since the pollutants are dependent on the raw materials
used. All the waste waters generated in the chrome pigments
subcategory contain dissolved chromium and pigment particulates.
Additional pollutants that can
for each major pigment group.
be present are given below
Chrome yellow and chrome
contain sodium acetate, sodium
sulfate, and lead salts.
orange: The raw waste waters
chloride, sodium nitrate, sodium
Chromic oxide: The aqueous process effluent contains sodium
sulfate. If boric acid is used in the preparation of hydrated
chromic oxide then the waste water will contain sodium borate and
boric acid.
Chrome yellow and chrome orange: Additional pollutants
present in the raw waste water from chrome yellow and chrome
orange manufacture include sodium acetate, sodium chloride,
sodium nitrate, sodium sulfate and lead salts.
Molybdenum orange: Process waste effluents from the
manufacture of molybdenum orange contain sodium chloride, sodium
nitrate, sodium sulfate, chromium hydroxide, lead salts and
silica.
Chrome green: The raw waste water contains sodium nitrate.
389
-------
'3H2°
ZnO
}
WATER
U)
UD
O
^
IC1 fc
KC1 ^
1
REACTION TANK
FILTRATION
AND
WASHING
DRYING
.MILLING, PACKAGING
OF THE ZINC YELLOW
-------
TABLE 16-5. WATER USAGE IN THE CHROME PIGMENTS SUBCATEGORY
Pigment
Plant
Water Usage, m /kkg of Product
Non-Contact Consumed in Boiler
Cooling Product Feed
Chrome Yellow
and Chrome Orange
Molybdate Chrome
Orange
Zinc Yellow
Chrome Oxide
#409
#894
#002
#002
#409
#894
#002
#409
#257
#894
6.6
—
3.1
5.0
0
0
0
6.3
0.35
4.7
1.8
3.3
1.0
1.3
8.4
3.5
1.0
0.8
4.2
2.0
__
11
NA
NA
NA
3.5
NA
NA
4.2
1.7
NA
391
-------
WATER
WASH VCVTER
WASH DOWN WATER
RAW MATERIALS .^
MILLING AND
SCREENING
NJ
f
T
PIGMENT
PRODUCTS
TO
PACKAGING
WASTE l-IATER
(BY-PRODUCT SALTS,
UNREACTED MATERIAI^,
ETC.)
NON-COMEACT
STEAM
PIGMENT
PARTICUIATE
WASTE
Figure 16-7. General process diagram for production of chrome pignent complexes.
-------
TABLE 16-6. AQUEOUS PROCESS WASTE EFFLUENTS IN CHROME PIGMENTS SUBCATEGORY
Pigment
Plant
Process Waste Water, m /kkg of Product
Chrome Yellow and
Chrome Orange
#409
# 894
#002
Molybdate Chrome Orange #002
# 409
# 894
Zinc Yellow #002
#409
Chrome Green #894
Chrome Oxide #257
# 894
44
120
35
31
40
110
20
19
48
29
31
393
-------
If iron blue is manufactured on site as part of the process for
chrome green manufacture, the waste water also contains sodium
chloride, ammonium sulfate, ferrous sulfate, sulfuric acid and
iron blue pigment particulates.
Zinc yellow: The raw wastes contain hydrochloric acid,
sodium chloride, potassium chloride, and soluble zinc salts.
As previously discussed, various plants make several chrome
pigments sequentially or concurrently. Thus the unit hydraulic
load going to the treatment facility will be an average of all
the waste loads from the different processes. The raw waste from
a complex plant may contain nearly all of the following
substances: sodium acetate, sodium chloride, sodium nitrate,
sodium sulfate, potassium chloride; lead, iron, and zinc salts,
soluble chromium and pigment particulates.
Control and Treatment Practices
Plant |894 was visited during the screening phase of the
program. This plant produces over 100 products including organic
pigments such as copper phthalocyanine, and all the wastes are
combined and treated together. Treatment consists of chr-omium VI
reduction, equalization and neutralization, followed by
clarification and filtration. Sulfur dioxide is added to reduce
the hexavalent chromium to the trivalent state at a low ph prior
to hydroxide precipitation. The backwash from the sand filters is
recycled to the equalization tank, while the sludge from the
clarifiers is passed through filter presses and then hauled to a
landfill. The landfill has a bottom of two clay layers with
gravel in between to allow the collection of leachate drainage.
Any water from the sludge is trapped in the gravel layer, and is
pumped out and returned to the plant for retreatment.
Figure 16-8 shows the treatment system flow diagram with the
sampling points indicated. Table 16-7 gives waste flows and
pollutant loadings.
Plant #002 was visited during the verification phase of the
program. Normally this plant has a product mix of over 100
pigments most of whicn are produced in batch processes. At the
time of sampling, zinc chromate was being produced by the
continuous production unit. During an eight week cycle the
continuous unit produces zinc chromate for one week and lead
chromate for seven weeks. All process contact wastes are treated
continuously. The waste is pumped to a treatment tank where S02
is added to convert hexavalent chromium to the trivalent state.
The ph is adjusted to 8.5 and then the waste is passed through
precoated filters followed by discharge to the sewer. Figure
16-9 shows the treatment flow diagram and sampling points. Table
16-8 shows the waste flows and pollutant loadings. At sample
394
-------
WASTE
SLAKED
LIME
WASTE
WATER
01
(EPA SAMPLE
POINT ALSO)
EQUALIZATION
TANK
NEUTRALIZATION
TANK
pH 6.2-6.5
1
NEUTRALIZATION
TANK
pH 8.0-8.3
U>
iX>
LT1
POLYMER
-e-
CLAR1FIER
EFFLUENT
IDLDING
TANK
(3) CLARIFIERS
(EPA SAMPLE
POINT ALSO)
FINAL
DISCHARGE
TO RIVER
Sample points.
Figure 16-8. General waste water treatment process flow diagram at plant #894
showing the sampling points. (Chrome Pigment Manufacture)
-------
TABLE 16-7. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED
WASTE STREAMS FOR PLANT #894 PRODUCING CHROME
PIGMENTS
Stream
Flow TSS Cr Fe Pb Cu
m3/kkg kg/kkg kg/kkg kg/kkg kg/kkg kg/kkg
Treatment
Influent
Treatment
Effluent
Leachate
Sand Filter
100
100
NA
100
78
0
1
.1
.393
NA
.1
7
0
0
0
.93
.032
.258
.060
4
0
0
0
.9
.03
.39
.10
1
0
0
0
.52
.011
.164
.068
0
0
0
0
.356
.004
.008
.000
Feed
TABLE 16-8. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT #002 PRODUCING CHROME PIGMENTS
Stream
Untreated
Waste
Flow
m^/kkg
85.6
TSS
kg/kkg
59.8
Cr
kg/kkg
26.25
Zn
kg/kkg
4.64
Pb
kg/kkg
13.94
Unfiltered 85.6
Treated Waste
Filtered 85.6
Treated Waste
N.A.
82.94
11.14
29.90
0.128 10.02
4.25
14.31
N.A. = Not Analyzed
396
-------
PAW WASTE SO- ACID
QIRCME TREATMENT
TANK
pH 3.0
CAUSTIC
LO
^D
--J
3ACKWASH
| (FILTERS NOT WORKING SO
| WERE BEING BYPASSED,
tTHIS WOULD BE THE FLOW
PATTERN IF FILTERS WERE
OPERATING.)
8
Sarrpling points.
OUTFALL
TO SEWER
Figure 16-9. General waste water treatment process flow diagram at Plant #002
showing the sampling points.
(Chrome Pigment Manufacture)
-------
point #2, half the sample was filtered through a glass fiber
filter on a Buechner funnel to simulate the filtration process
which was being bypassed at the time of sampling. Analyses were
carried out done on the filtered and unfiltered samples in order
to make possible a comparison of the total and dissolved
concentrations.
At Plant #464, the chrome pigment process wastes are sent to
a settling basin and an discharged to a sewer.
Plant #502 discharges its wastes directly to the sewer.
At Plant #409, the waste waters from the zinc yellow process
plant are collected and passed through two ion exchange columns
to recover chromate values which are returned to the process.
The effluent from the ion-exchanger is treated with soda ash to
precipitate zinc salts as zinc carbonate, which is filtered to
recover zinc carbonate.
At one plant the waste waters from the zinc yellow process
are acidified to dissolve the hexavalent chromium and then
treated with sulfur dioxide to reduce the hexavalent chromium to
the trivalent state. The solution is then reacted with caustic
soda for metal precipitation. The reacted solution is filtered
and the filtrate is discharged (52) .
At another chrome pigment manufacturing complex, plant waste
waters are collected and treated with sulfur dioxide in acid
solution followed by lime addition in two stages to give a pH in
the range 7.5-8.5. The metals are precipitated by the treatment.
The slurry is further treated with sodium sulfide for additional
precipitation of metals. The reacted solution is flocculated and
sent to a clarifier. The overflow from the clarifier is passed
through mixed media filters before discharge. The clarifier
underflow is filtered in a plate and frame filtration unit and
the solids are land filled. The filtrate is returned to the
clarifier (52) .
Best Management Practices and Technology Transfer Options
1. All storm water and surface area runoff from the plant
site can be collected and sent to the treatment facility-
2. If the solids from the treatment plant are disposed of
on-site provision should be made to control leachates and
permeates, it is possible to monitor the metal concentrations and
when concentrations approach predetermined limits, the leachate
can be pumped bacK to the treatment system for further treatment.
398
-------
Model Plant and BPT Level Treatment System Specifications
The BPT treatment system for chrome pigment wastes consists
of:
A. Acifidification in a recirculated holding tank.
B. Reduction with sulfur dioxide to convert hexavalent
chromium to its trivalent state.
C. Addition of caustic soda to precipitate chromium
and other heavy metals.
D. Polymer-assisted clarification to settle metallic
hydroxides.
E. Filtration to remove fine suspended matter.
Production in the industry ranges from 3500 kkg/yr to 20,000
kkg/yr. For the model plant four production rates were chosen:
1,500, 4,000, 6,000 and 18,000 kkg/yr. These cover the entire
range of production rates. Most plants produce many chrome
pigment products on a continuous basis so the operational mode
selected was continuous and assumed to run 350 days per year.
Chrome pigments are usually produced in integrated facilities
with the necessary flexibility to shift from one product or
combination of products to another. The model plant was selected
to reflect this type of complexity. The observed waste flows
varied from 19 m3/kkg to 150 m3/kkg. The value of 105 m3/kkg was
selected as the model plant waste flow.
Pollutant loads - For the model plants, the loadings are
based on screening and verification plant data as well as
loadings presented in previous EPA documents. The loadings used
for the model plant were 8.5 kg chromates as chromium per kkg of
product and 50 kg suspended solids per kkg of product.
Chemicals required - The calculated quantity of caustic soda
required to raise the pH to 8.5 is 400 mg/1. The unit caustic
soda requirement 45 kg/kkg of product. Sulfuric acid and sulfur
dioxide are used at 67.5 and 40.75 kg per kg of chrome pigment
respectively.
Generation p_f Solids Sludge solids are composed of
suspended solids (given above as 50 kg/kkg) and the solids
generated as reaction products. Considering chromium hydroxide
as the major insoluble reaction product, the unit quantity is 17
kg/kkg of product. The total solids to be hauled to a secure
landfill is 67 kg/kkg of product.
399
-------
16.2 TECHNOLOGY BASED POLLUTION ABATEMENT
16.2.1 Advanced Level Treatment Applications
priority Pollutants to be Controlled
The priority pollutants found in significant amounts are the
heavy metals contained in the chromium ore, including chromium,
antimony, copper, cadmium, nickel, lead, and zinc. In sorae raw
wastes, ferro- and ferricyanide are found, presumably from metal
complexing steps in the ore processing and the manufacture of
iron blues. These complex cyanides may pass through the model
treatment processes and could slowly revert to simple cyanide
ions.
Removal Technologies Available
All of the common heavy metals (except hexavalent chromium)
found in chrome pigment wastes will be precipitated by alkaline
substances such as lime or caustic soda, although the optimum pH
may differ for each metal. Reaction with sulfide compounds such
as sodium bisulfide will precipitate the same metals, except in a
less pH-dependent manner and, with the exception of chromium, to
lower co-Fveentrations. Chromium in its hexavalent form can be
reduced to its trivalent form and then precipitated as chromium
hydroxide at a pH above 10.
Technology to be Applied at Each Level
BPT (Level !_)_ - Incoming wastes are acidified and reduced
prior to alkaline precipitation. Settling and filtration are
used to remove suspended solids.
Level 2_ - For better separation of the trace metals, sulfide
precipitation is incorporated ahead of the BPT dual media filter.
Flow Diagrams
Level 1 Figure 16-10
Level 2 Figure 16-11
Equipment Functions - In both levels, the incoming wastes
are acidified in a holding tank and then treated with sulfur
dioxide solution in a reactor to convert hexavalent chromium to
trivalent chromium. Caustic soda is added as a precipitant and
400
-------
r~
BACKWASH
SULFURIC
ACID
Q CAUSTIC SODA
LJ
RAW
L
t .
WASTE' WATER" 1
3
I
SULFUR
DIP
JAIL)
1
h,
P0
f.
| HOLDING TANK REACTION MIX
TANK TANK
1
SUMP
CLARIFIER
SLUDGE
TANK
TO LANDFILL
Includes flow monitoring, pH monitoring and sampler.
ADJUSTMENT
*EFFLUENT
FILTER
Figure 16-10. Waste water treatment Level 1 for chrane pigments.
-------
FERROUS SULFATE SODIUM BISULFIDE
BACKWASH
CAUSTIC
I SODA
RAW
LJ SULFUR
\.
WASTE WATERl
DI(
&
D3
•CID
E
1
P
HOLDING TANK
REACTION MIX
TANK TANK
U-
SUMP
CLARIFIER
FILTER
SLUDGE
TO LANDFILL
Includes flow monitoring, pH monitoring and sampler.
EFFLUENT
Figure 16-11. Waste water treatment Level 2 for chrome pigments.
-------
polymer is added to help settle the heavy metal hydroxides in a
clarifier. The settled effluent is then filtered in a dual media
filter and discharged after ph adjustment to the range 6 to 9.
In Level 2, ferrous sulfide is added ahead of the dual media
filter, for more effective precipitation of all the residual
heavy metals, including antimony. As in Level 1, the filter
effluent is adjusted to a ph between 6 and 9 before discharge.
Chemicals and handling - Sulfuric acid and caustic soda
solutions are common industrial chemicals wnich are readily
handled with conventional liquid feeding equipment. Sulfur
dioxide is received as a compressed gas which is dissolved in
water by a modified gas chlorinator and fed to the reactor to
maintain consistent reducing conditions. Polymer is fed by a
standard package of holding tank, mixer and feeder. With normal
precautions, there are no unusual hazards in handling chemicals
for treatment of chrome pigment wastes.
Separation and Pi sposal of Sol ids - Solids from the
clarifier, including recirculated filter backwash solids, are
dewatered in a filter press and hauled to a chemical landfill.
Sludge filtrate is returned to the influent holding tank.
Monitoring Requi rements - Internal process monitoring
consists of maintaining proper ph levels in the holding tank and
final effluent, using conventional field equipment. A reducing
environment is maintained in the reactor, using an
oxidation-reduction potential instrument and/or the analysis for
excess S02. Periodic effluent analyses for chromium and the
trace heavy metals should be made on composite samples by atomic
absorption methods, for official reporting purposes. Sulfide
monitoring is unnecessary because dissolved sulfides should not
exist in the presence of excess ferrous iron and oxygen.
16.2.2 Estimated Performance of BPT Systems
Pollutants previously regulated in this subcategory include
suspended solids, hexavalent chromium, total chromium, lead, and
zinc. Where iron blues are manufactured, iron, total cyanide and
oxidizable cyanide are regulated. Raw waste priority pollutants
found in significant concentrations during screening and
verification sampling were presented earlier. Selected
pollutants which may require regulation in addition to those
listed above include antimony, cadmium, copper and nickel.
Waste water treatment at chrome pigment facilities ranges
from simple settling and discharge to chemical reduction,
precipitation and filtration. One facility uses ion exchange for
treating wastes from a single product.
403
-------
At Plant #894, a complex facility also producing organic
pigments, treatment consists of equalization, reduction of
tiexavalent chromium, lime addition to
sedimentation, biological oxidation and filtration prior
discharge. Table 16-9 presents effluent monitoring
verification sampling results from this plant.
precipitate metals,
to
and
At Plant #002, another complex facility, waste water
treatment consists of reduction of hexavalent chromium,
neutralization with caustic, and filtration prior to discharge to
a POTW. During verification sampling, the treatment system was
not operating efficiently so analytical results were
inconclusive.
BPT technology has been specified in Section 8 as reduction
of hexavalent chromium, hydroxide precipitation of metals,
clarification, and filtration for suspended solids removal.
Important to treatment efficiency is sufficient equalization
capacity to control waste variations and surges.
Base Level Performance Characteristics for BPT Pollutant Removal
Based on data presented in Table 16-9 and on the discussion
of the reduction of hexavalent chromium with sulfur dioxide and
other raetals with hydroxide precipitation, achievable treated
effluent quality with implementation of BPT technology is
presented in Table 16-10.
Base Level
Removal
Performance Characteristics for Priority Pollutant
Additional priority pollutant metals found in chrome
pigments raw waste were antimony, cadmium, copper and nickel.
Based on verification sampling results shown in Table 16-9 and on
the hydroxide treatability discussion in Section 8,
implementation of BPT technology will achieve the treated
effluent quality presented in Table 16-10.
Pretreatment Applications
Several chrome pigment plants discharge waste water to POTWs
and removal of incompatible heavy metal pollutants is necessary.
BPT technology for pretreatment of chrome pigments waste
waters is recommended.
404
-------
TABLE 16-9. MONITORING AND VERIFICATION SAMPLING OF CHROME PIGMENTS FLAW
#894
Verification Sampling:
Pollutant
Influent
3 mg/1
Avg Flow (m /kkg)
Total Suspended
Solids, TSS
Chromium, Cr
Chromium VI, Cr
Iron, Fe
Lead, Pb
Zinc, Zn
Cyanide, CN
Cyanide (Free) , CN
XT.
Antimony, Sb
Cadmium, Cd
Copper, Cu
Nickel, Ni
780
78
<0.01
49
15.2
4.2
5.1
<0.94
0.74
0.90
3.56
0.017
kg/kkg
78
7.8
<0.001
4.9
1.52
0.42
0.51
<0.094
0.074
0.090
0.36
0.0017
Effluent
mg/1
153
3.9
0.32
<0.03
0.30
0.11
0.058
<0.066
<0.011
0.30
0.0084
0.04
<0.024
kg/kkg
0.39
0.032
<0.003
0.03
0.011
0.0058
<0.0066
< 0.0011
0.030
0.00084
0.004
<0.0024
Monitoring Data - Treated Effluent
Total Suspended Solids, TSS
Chromium VI, Cr
Chromium, Cr
Copper, Cu
Lead, Pb
Zinc, Zn
Cyanide (Free) , CN
Cyanide (Total) , CN
Arsenic
Cadmium
Mercury
<
<
Avq
30 day Avq Waste Load (Avg)
Concentration mg/1
11.2 23.5
0.11 0.3
0.44
0.13
0.41
0.044
: 0.012
0.12
0.08
0.08
: 0.001
0.73
0.25
0.87
0.075
0.044
0.31
0.16
0.12
0.0017
kg/kkg
1.92
0.018
0.074
0.023
0.069
0.0072
0.0019
0.019
0.0125
0.013
0.00007
405
-------
TABLE 16-10 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Chrome Pigments
Level of Treatment: 1
Waste Water Flow: 100 m3/kkg
Quality Limit Emission Limit
Subcategory (1) (mg/1) (kg/kkg)
Pollutant Performance VFR
(mg/1) 30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants:
Total Suspended 22 2.0 15 30 1.5 3.0
Solids, TSS
Total Chromium,
Cr
Hexavalent
Chromium, Cr+6
Iron, Fe
Lead , Pb
Zinc, Zn
Cyanide, CN
Oxidizable
Cyanide, CN(A)
Proposed Priority
Pollutants
Copper, Cu
Nickel, Ni
0.73
0.30
(2)
0. 3
0.87
0.07
0. 31
0.04
0.25
(2)
0.05
3.
3.
2.
2.
2.
4.
4.
2.
2.
0
0
0
0
0
0
0
0
0
1.
0.
1.
0.
0.
0.
0.
0.
0.
0
2
0
8
4
5
05
3
1
3.0 0.
*
0.6 0.
2.0 0.
1.6 0.
0.8 0.
2.0 0.
0. 2 0.
0.6 0.
0. 2 0.
1
02
1
08
04
05
005
03
01
0.
0.
0.
0.
0.
0.
0.
0.
0.
3
06
2
16
08
2
02
06
02
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Verification Sampling
406
-------
Response to Remand Issues
Major remand issues of BPT limitations in this subcategory
were the following:
1. The accuracy and reliablity of the analytical method for
hexavalent chromium in chrome pigments waste waters and the
possible deletion of hexavalent chromium in favor of total
chromium as a control parameter. Industry has shown that certain
waste constituents can cause a reducing environment which
interferes in the analysis of hexavalent chromiun leading to low
results. Industry has recommended an alternative analytical
technique which has yet to be accepted. The questions regarding
the present analytical method need to be resolved. However, the
high toxicity of hexavalent chromium necessitates the regulation
and control of this pollutant.
2. The treatability of particular pollutants found in the
raw waste loads, including the achievable levels with mixed
effluent streams. Industry has questioned the transfer of
technology from the electroplating industry. The achievable
effluent quality presented above is based on available data on
the treatability of mixed wastes and takes into account the
variability of wastes encountered in this subcategory.
16.2.3 Estimated Performance of Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
Table 16-11 presents estimates achievable effluent quality
through implementation of this advanced technology.
New Source Applications
Following examination of treatment technologies applicable
to new chrome pigment facilities, it has been determined that
effluent quality achievable through the implementation of the
above advanced technology is appropriate for NSPS.
16.2.4 Cost Estimates
Discussion
Cost estimates for models having four different production
rates and two levels of treatment are presented in Tables 16-12,
16-13, 16-14, and 16-15. Annual treatment cost as a function of
407
-------
TABLE 16-11 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Chrome Pigments
Level of Treatment: 2
Waste Wa-ter Flow: 100 m3/kkg
Quality Limit Emission Limit
(1) (mg/1) (kg/kkg)
Pollutant Treatability VFR
(mg/1) 30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants ;
Total Suspended
Solids, TSS
Total Chromium,
Cr
Hexavalent
Chromium, Cr+6
Iron, Fe
Lead, Pb
Zinc, Zn
Cyanide, CN
Oxidizable
Cyanide, CM (A)
Proposed Priority
Pollutants
Copper, Cu
Nickel, Ni
15
0.
0.
1.
0.
0.
0.
0.
0.
0.
05
2
0
1
2
5
05
05
1
2.
3.
3.
2.
2.
2.
4.
4.
2.
2.
0
0
0
0
0
0
0
0
0
0
15
1.
0.
1.
0.
0.
0.
0.
0.
0.
0
2
0
1
2
5
05
05
1
30 1.
3.0 0.
0.6 0.
2.6 0.
0. 2 0.
0.4 0.
2.0 0.
0.2 0.
0. 1 0.
0. 2 0.
5
1
02
1
01
02
05
005
005
01
3.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0
3
06
2
02
04
2
02
01
02
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
408
-------
TABLE 16-12 MODEL PLANT TREATMENT COSTS
Subcategory CHROME PICMENTS Type of Regulation BAT
Production 1,500 metric tons per year ( 1,653 tons per year)
4 metric tons per day ( 4 tons per day )
Waste water flow 454 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $36,800 $500
Equipment in place,
including piping,
fittings, electrical
work and controls 280,650 6,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 65, 290 1,300
Incidentals, overhead,
fees, contingencies... 65,290 1,300
Land 6,000
TOTAL INVESTMENT COST $463,030 $9,100
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $112,000 $14,000
Energy 7,350 300
Chemicals 53,000 2,200
Maintenance 45,703 910
Taxes and insurance... 13,890 273
Residual waste
disposal 5,000
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $251,943 $25,183
C. AMORTIZATION OF
INVESTMENT COST $74,358 $1,480
TOTAL ANNUAL COST $326,301 $26,663
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
409
-------
TABLE 16-13 MODEL PLANT TREATMENT COSTS
Subcategory CHROME PIGMENTS
Production
Type of Regulation BAT
4,000 metric tons per year ( 4,410 tons per year)
11 metric tons per day ( 12 tons per day )
Waste water flow 1219 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, coatingencies...
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Maintenance
Taxes and insurance...
Residual veste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
WORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
LEVEL OF TREATMENT*
FIRST SECOND
$53,900
510,000
9,000
114,580
114,580
12,000
$814,060
$112,000
15,000
141,300
80,206
24,421
15,000
15,000
$402,927
$130,495
$533,422
$1,000
10,000
2,200
2,200
$15,400
$14,000
300
5,900
1,540
462
7,500
$29,702
$2,505
$32,207
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
410
-------
TABLE 16-14 MODEL PLANT TREATMENT COSTS
Subcategory CHRCME PIGMENTS
Production
Waste water flow
Type of Regulation BAT
6,000 metric tons per year ( 6,615 tons per year)
17 metric tons per day ( 18 tons per day )
1820 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, conting enc ies...
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Ma intenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and repo rting
TOTAL OPERATION AND
MAINTENANCE COST
AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
LEVEL OF TREATMENT*
FIRST SECOND
$71,400
667,000
9,000
149,480
149,480
12,000
$1,058,360
$112,000
20,200
211,500
104,636
31,750
20,000
15,000
$515,086
$170,242
$685,328
$1,000
14,000
3,000
3,000
$21,000
$14,000
300
8,800
2,100
630
7,500
$33,330
$3,416
$36,746
*First level represents the base cost of treatment system.
Other levels represent the incranental cost above base cost.
411
-------
TABLE 16-15 MODEL PLANT TREATMENT COSTS
Subcategory CHROME PIGMENTS
Type of Regulation BAT
Production 18,000 metric tons per year ( 19,845 tons per year)
51 metric tons per day ( 56 tons per day )
Waste water flow 5460 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $205,500 $2,000
Equipment in place,
including piping,
fittings, electrical
work and controls 1,495,500 30,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 342,000 6,400
Incidentals, overhead,
fees, contingencies... 342,000 6,400
Land.,- 18,000
TOTAL INVESTMENT COST $2,412,000 $44,800
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $112,000 $14,000
Energy 28,000 600
Chemicals 635,000 26,400
Maintenance 239,400 4,480
Taxes and insurance... 72,360 1,344
Residual vaste
disposal 60,000
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST
C. MCRTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$1,161,760
$389,503
$1,551,263
$54,324
$7,288
$61,612
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
412
-------
production is shown graphically in Figure 16-12. Treatment cost
per metric ton of product is given in Figure 16-13.
Table 16-16 shows a summary of the unit cost distribution
between amortization and the operation and maintenance cost
components at various production rates and levels of treatment.
Summary
Cost estimates for
amortization, chemicals,
the total annual costs.
first level of treatment indicate that
and labor have a significant impact on
At the second level of treatment, additional labor and and
monitoring costs have significant impact on the annual costs.
4-13
-------
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o
o
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ti
PRCDUCTICN, METRIC TCNSAEAR X 1000
Figure 16-12. Annual treatment cost vs. production for the
Chrome Pigments Subcategory
414
-------
240-
220 •
200,
180-
160 .
140
120
\
100
LEVEL #2
80
EEVEL"
6 9 12
PKXXJCTLW, METFilC TONS/YEAR X 1000
15
18
Figure 16-13. Annual unit treatment cost vs. production for the
Chrome Pigments Subcategory
415
-------
TABLE 16-16 MODEL PLANT TREATMENT COSTS
Subcategory CHROME PIGMENTS
Type of Regulation BAT
Annual Treatment Costs ($/kkg)
LEVEL OF TREATMENT
PRODUCTION FLOW FIRST SECOND THIRD FOURTH
(kkg/yr) (m3/day) $ $ $ $
Annual Operation
and Maintenance
Annual
Amortization
Total Cost
1,500
4,000
6,000
18,000
1,500
4,000
6,000
18,000
1,500
4,000
6,000
18,000
454
1,219
1,820
5,460
454
1,219
1,820
5,460
454
1,219
1,820
5,460
167.96
100.73
85.85
64.54
49.57
32.62
28.37
21.64
217.53
133.36
114.22
86.18
16.79
7.43
5.56
3.02
0.99
0.63
0.57
0.40
17.78
8.05
6.12
3.42
Not Applicable
416
-------
SECTION 17
HYDROGEN CYANIDE INDUSTRY
17.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL OF THE ANDRUSSOW
PROCESS
17.1.1 Industry Profile and Analytical Results
Over 50 percent of the Hydrogen Cyanide manufactured is
produced by the Andrussow process, while about 40 percent is a
by-product from acrylonitrile manufacture. A major portion of
the production is used in the manufacture of methyl methacrylate
for lucite, plexiglas molding and extrusion powders, and surface
coating resins. It is also used as a fumigant for orchards and
tree crops.
The industrial data profile for this industry is given in
Table 17-1, while the existing regulations are given in Table
17-2.
Priority pollutants found at significant levels in raw
wastes during sampling at Andrussow Process plants were as
follows:
Maximum Concentrations
Pollutant Screening*
(ug/1)
Verification
(2 Plants)
Cyanide
Tnallium
*Includes
other
cyanide
166
25
process wastes
186
No sample
taken
The thallium detected is believed to be not related to the
HCN process, but rather to metal cyanide processes at the same
plant.
A summary of daily and unit product raw waste loads for all
Plants sampled can be found in Table 17-3. Individual plant raw
waste loads per unit product found in sampling can be found in
Table 17-4.
Based on the total annual production of this subcategory and
the average waste load generated per unit product, the estimated
total priority pollutant raw waste loads generated each year for
subcategory are as follows:
417
-------
TABLE 17-1
SUBCAIEGORir PROFILE DATA SUMMARY
SUBCATEGORY
HYDROGEN CYANIDE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
289,000 kkg/year
165,500 kkg/year
11
3
218,000 kkg/year
136,000 kkg/year
75 percent
82 percent
8,500 kkg/year
64,600 kkg/year
57,800 kkg/year
57,800 kkg/year
65 percent
3 years
9 years
1,150 cubic meters/day
7,310 cubic meters/day
6 cubic meters/kkg
50 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
418
-------
17-2 -
EXISTING IMPUTATIONS - EFFLUENT LIMITATICN GUIDELINES
SUBCMTEGOKT Hydrogen Cyanide
SUBPAKT AP (40CFR 415.420, 5/22/75)
STANDARDS
Product Para-
Process meters
Andrussow ^s
Process
CN
CN(A)
BOD5
NH3 N
BPCTCA* BATEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
(mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
2.4
(48.0)**
0.05
(1.0)
0.005
(0.1)
3.6
(72.0)
0.36
(7.2)
1.2
(24.0)
0.025
(0.5)
0.0025
(0.05)
1.8
(36.0)
0.18
(3.6)
Sections 415.420, 415.421, and 415.422 were revoked by the Agency
|41 FR 10681, February 23, 1977) .
wax. = Maximum of any one day,
Avg. = Average of daily values for thirty consecutive days shall not exceed.
**
flow basis 50,000 1/kkg.
419
-------
TAliL^E 17-3. SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
to
o
"
SUBCATEGORY
Pollutant
Priority
Total
Cyanide, CNT
Free
Cyanide, CN
Conventional
TSS
NH3-N
BCDC
HYDROGEN CYANIDE
Loadings
kg/day
Minimum Average Maximum Minimum
173 205 237 0.81
106 113 120 0.49
152 383 614 1.02
3881 5793 7705 26.2
24.5 4323 8621 0.16
kg/kkg No. of Plants
Average Maximum Averaged
1.20 1.60 2
0.65 0.81 2
1.94 2.87
31.1 36.0
20.2 40.3
-------
SUBCATEGORY
17-4. PRIORITY POLLUTANT RAW WASTE LOADS Cin kg/kkg of Product)
HYDROGEN CYANIDE
POLLUTANT
PLANT
#765 # 782
#765
Total Cyanide, CNT
Free Cyanide, CNA
Thallium, Tl
5.9
NA
0.0014
0.808
0.49
1.6
0.807
NA = Not Available
421
-------
Pollutant
Waste Load (kg/year)
Cyanide (Total)
Cyanide (Free)
200000
110000
17.1.2 Process Waste Sources and Waste Water Treatment Data
General Process Description
The hydrogen cyanide subcategory in this study is confined
to the Andrussow process, in which air, ammonia and methane are
reacted to produce hydrogen cyanide.
The raw materials are reacted at elevated temperatures
(900-1000 Degrees C) over a platinum catalyst. The reaction is
given as:
2CH4 + 2NH3 + 302 = 2HCN + 6H20
(1)
The source of methane is natural gas containing 50 to 100
volume percent methane. In addition to hydrogen cyanide, the
reacted gases contain ammonia, nitrogen, carbon monoxide, carbon
dioxide, hydrogen and small amounts of oxygen, as well as traces
of organic nitriles formed from nonmethane components of natural
gas. The reactor gases are cooled and then scrubbed in one of
two processes which are used to remove the unreacted ammonia. In
one patented process the gases are scrubbed with phosphate liquor
and the resulting solution is decomposed and the phosphate
solution is recirculated. The recovered ammonia is recycled to
the reactor. In the second process sulfuric acid is used to
absorb ammonia from the reactor gases. At one plant the
resulting ammonium sulfate solution is used for the manufacture
of another product.
The hydrogen
effluent gases by
are vented to the
hydrogen cyanide,
produce HCN gas of
cyanide is removed from the ammonia scrubber
absorbtion in cold water, and the waste gases
atmosphere. The absorbed solution containing
water, and other contaminants is distilled to
over 99 percent purity.
The water produced during tiie initial reaction (Equation 1)
of the formation of nydrogen cyanide is purged with the
distillation bottom stream and is either recycled to the absorber
or discharged to the treatment facility. In order to be
recycled, the absorber water bottoms have to be cooled by
refrigeration prior to reuse in the HCN absorber unit. At plant
locations where cold water is readily available in large
quantity, it can be used on a once-through basis with a
422
-------
significant savings in energy costs. Figure 17-1 presents a
general block diagram for the manufacture of hydrogen cyanide by
the Andrussow process.
Water Use and Waste Source Inventories
Water usage - Water is used in noncontact cooling in the
absorber, pump seal quenches, flare stack flushes, for washdown
and cleanup of tank cars, and for washing equipment and cleaning
up leaks and spills. Table 17-5 gives the detailed water
consumption at one plant and also the total consumption at two
plants. The difference in water usage at these two plants is
pronounced due to the use of refrigeration at one plant, and
once-through cooling water at the other.
Waste sources - The following are the sources of waste water
produced from the manufacture of hydrogen cyanide by the
Andrussow process.
A. Distillation bottoms: The waste water contains ammonia,
hydrogen cyanide and small amounts of organic nitriles. The
water consists of the water produced by the reaction plus
scrubber water used for the absorption of HCN. The absorption
water distillation bottoms are either recycled to the ammonia
absorber or discharged to the treatment facility. Even if the
distillation bottom stream is recycled to the absorber, a portion
of it is discharged to stop the build up of impurities.
B. Scrubber streams: If the scrubber liquid is recycled, a
portion of it has to be purged to control the accumulation of
impurities. The bleed contains the acid used for scrubbing and
minor amounts of organic nitriles. The scrubber solution can
also be used for the manufacture of other products in whicn case
nothing is discharged from the scrubber operation.
C. Other waste water: This includes leaks and spills,
equipment and tank car washings, noncontact cooling water
blowdown and rainfall runoff. The tank cars are washed out with
dilute acid or alkali to remove any contaminants present, which,
if allowed to remain in the tank car, can polymerize the hydrogen
cyanide causing safety hazards due to possible explosion during
shipment. The noncontact cooling water may be contaminated with
the product as a result of leaks. The recirculated cooling water
is monitored for cyanide and the cooling tower blowdown is
discharged to the waste water treatment facility. During shut
down, the equipment is drained to avoid freeze-up and the
resulting waste water is discharged to the treatment facility.
423
-------
ACID
COLD
WATER
VINT
GASES
METHANE
AIR
AMMONIA
£»
f
REACTOR
AMMONIA
ABSORBER
HCN ABSORPTION
DISTILLATION
1
I1CN PRODUCT
T
USED FOR THE
MANUFACTURE OF
OTHER PRODUCTS
OR RECYCLED.
WHEN RECYCLED,
A BLEED IS SENT
TO THE WASTE
TREATMENT PLANT.
A PORTION OF THE
DISTILLATION BOTTOM
IS RECYCLED TO THE
ABSORBER. AFTER
COOLING THE REST IS SENT
TO THE TREATMENT
FACILITY.
Figure 17-1.
General process flow diagram for production of hydrogen cyanide by
the Andrussow Process.
-------
17-5. WATER USAGE IN HYDROGEN CYANIDE - ANDRUSSOW PROCESS
SUBCATEGORY
plant Water Usage, m /kkg of HCN
Total Consumption Non-contact Cooling
' 29
|782 y>
#765
58.3
(1) 3
Detail water usage (m /kkg) at Plant #782 is:
Non-contact cooling = 18.9
Direct process contact = 7.45
Indirect process contact = 0.71
(pumps, seals, leaks,
spills, etc.)
Maintenance, e.g. cleaning = 0.313
and work area washdown
Non-contact ancillary uses = 0.67
(boilers, utilities, etc.)
Exported steam = 1-44
425
-------
Control and Treatment Practices
Plant #765 was visited and the waste water sampled duriny
the screening phase of the program. The combined wastes consist
of distillation bottoms, ammonia recovery purge liquor, tank car
washings, leaks, spills and equipment clean out, purge from the
noncontact cooling water system and stormwater water runoff.
These combined wastes are commingled with the other cyanide
production waste waters and sent to the alkaline chlorination
treatment facility. This consists of a trench, where the pH is
adjusted to 10 with dilute caustic, followed by two ponds.
Sodium hypochlorite is added at the pond inlets. The effluents
from the ponds are discharged to a third pond where sufficient
chlorine and caustic are added to reach the required effluent
quality; namely, an oxidizable free cyanide residual of 0.1 ppm
and a residual chlorine of about 15-20 ppm. The third pond is
operated on a continuous flow mode and is baffled to control
circulation. Agitation is provided in the flow channel, and the
outlet is equipped with a control device to stop the flow when
the effluent cyanide concentration exceeds the desired level.1
Figure 17-2 is a flow diagram of the treatment process indicating
the sampling locations used during the screening program. Table
17-6 gives the flow and pollutant data for the sampled streams.
A comparison of the raw and treated effluent data in the table
indicates that the plant achieves a cyanide reduction of 99
pe rcent.
Studies indicate that the presence of ammonia tends to
decrease the effectiveness of cyanide destruction by alkaline
chlorination by competing for the chlorine. Plants having good
ammonia recovery systems are able to mitigate this type of
interference, and improve performance. A major concern with
alkaline chlorination of hydrogen cyanide waste is the
possibility that chlorinated organics might be produced. At this
plant extensive sampling and analysis of the treated effluent
showed the absence of chlorinated organics above the detection
limit of 50 ppb.
The second hydrogen cyanide plant sampled in the
verification phase was Plant #782. The process waste water from
the hydrogen cyanide plant is combined with other production
waste waters and sent to a complex biological treatment system.
A part of the commingled waste water is sent to an ammonia
stripper from which the aqueous effluent is mixed with the rest
of the waste water and sent to the treatment facility. The
primary treatment facility consists of oil skimmers, grit removal
and pH adjustment. The effluent from the primary treatment goes
through an API separator and into an aerated lagoon. The
effluent from the lagoon is flocculated and sent to a clarifier.
The overflow from the clarifier is sent to a final settling basin
before discharge. The surface drainage from the hydrogen cyanide
and other process areas is collected separately. This is treated
426
-------
HYDROGEN CYMJIDE
WRSTE WATER
K)
OTHER CYANIDE PRCtWCT
WATER
DILUTE CAUSTIC
Waste streams sampled
FINAL TREATED
EFFLUENT
Figure 17-2. General waste water treatment process flow diagram at Plant £765
showing the sampling points. (Hydrogen Cyanide Manufacture)
-------
TABLE 17-6. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT #765 PRODUCING HYDROGEN CYANIDE
Stream Unit Flow SS Load NH3~N Load CN Load
Description m3/kkg of HCN kg/kkg of HCN kg/kkg of HCN kg/kkg of HCN
Raw HCN waste
Influent to
57
57(1)
1.08
55.8(2)
27.2
11.07 (2'
0.82
0.388(2)
Treated
effluent from
the final pond
57(2),(3)
1.9
(2)
7.05
(2)
<0.000114
(2)
(1)
(2)
.(3)
The stream is a commingled waste water. The flow given is the amount
contributed by the HCN process.
The pollutant load was calculated by apportioning the mass emitted between
the two waste streams on the basis of measured flows. This is clearly a
very approximate process and the results must be used with caution.
The addition or loss of water from rainfall, addition of chemicals and
evaporation has not been estimated.
428
-------
chemically and passed through a trickling filter from which a
portion of the effluent is sent to the aerated lagoon and the
rest sent to the clarifier influent.
A general flow diagram of the treatment process including
the streams sampled is shown in Figure 17-3. Table 17-7 gives
the flow data and concentrations of the important pollutants.
Because of the intermixing of the various product waste waters
unit pollution loads are uncertain and are not given. The total
waste water generated from HCN manufacture and the amount going
to the treatment facility was verified during the plant visit and
was confirmed in the 308 Questionnaire response provided by the
industry. Based on that flow and the concentrations determined
by analysis, the raw waste load is:
Flow CN(T) NH3-N, TSS,
m3/kkg kg/kkg of HCN kg/kkg of HCN kg/kkg of HCN
Effluent from
Combined Plant 9-9 0.02 0.05 0.74
Waste Treatment
The load values assigned to the HCN process were estimated
by proportioning the total loads in relation to the respective
flow rates. The result is, therefore, approximate and must be
used with caution. In calculating the pollutant loads, the loss
or gain of water to the treatment system due to factors such as
evaporation, loss through filtered solids, precipitation and the
water introduced by treatment chemicals, has been neglected.
The final concentrations of cyanide and ammonia in the
treated effluent shown in Table 17-7 indicate that the treatment
system is efficient in the removal of these pollutants with
cyanide destruction exceeding 99 percent.
The quantity of waste water produced and treated at two
plants producing hydrogen cyanide by the Andrussow process is
given in Table 17-8. The large variation in flow is due to the
fact that at Plant #765 the water used to absorb the hydrogen
cyanide from the reactor gases is not recycled. As discussed
earlier, that plant is situated in a location where sufficient
cold water is available for once-through use. Since the cold
water is readily available at a low cost, the water used for
absorption is discharged. It is reported that a similar plant
Practicing recycling, in the absence of available cold water, can
achieve a total waste effluent of 7.1 m3/kkg of HCN.
429
-------
DISTILLATION
BOTTCM TORGE
OTHER PRCOOCT
WRS1E WATER
DRAIN
e
L/1HKU PRODUCT
WASTE WATER
Sanpling points
DISCHARGE
Figure 17-3. General waste water treatment process flow diagram at Plant #782
showing the sairpling points. (Hydrogen Cyanide Manufacture)
430
-------
17-7. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT#.782 PRODUCING HYDROGEN CYANIDE.
.
-
Stream
NO.
1
2
3
4
Waste
Stream
Description
Distillation
bottom purge
Artmonia stripper
influent
Ammonia stripper
effluent
Influent to
Flow
m /day
11.34
1143
1143
5564
CNT
rag/1
70
167
51.3
31
NH3-N
mg/1
887
410
41
1381
TSS
mg/1
24
76
162
110
primary treatment
facility
5 Final treated NA 2.2 5.16 74.3
effluent
= Not Available.
431
-------
TABLE 17-8. WASTE FLOW DATA FOR HCN PRODUCTION BY THE ANDRUSSOW
PROCESS
Plant Total waste going to the treatment facility (m /kkg)
#765 57
#782 9-9*
The breakdown and flow of the different waste streams comprising the total
is given below:
Source Unit Flow m /kkg
Recovery and purification 6.3
Pump seal quenches 0.58
Flare stack flushes 0.09
Sample hoods 0.02
NH., stripper caustic 0.24
Steam condensate from NH stripper 0.90
Freeze protection 0.06
Washdowns and cleanup 0.25
Boiler blowdown and condensate 1.48
432
-------
Model Plant and BPT Treatment System Specifications
Production - Eight plants produce hydrogen cyanide by the
Andrussow process at a total production rate of 165,000 kkg/yr.
Production and waste water flow data are on file for two plants
which produce a total of 116,000 kkg/yr or 70 percent of the
total United States production. (This is approximately 80
percent of the United States production by the Andrussow
process) . For waste water treatment cost estimates, three
production levels were selected for the model plant. These are
31,800, 50,900, and 63,600 kkg/yr.
Waste water flow - Unit waste water flows for the two plants
are 50 m3/kkg and 10 m3/kkg. The difference results from the two
plants having different absorption water discharge practices (see
earlier discussion). If recycling of absorber water were
practiced at the first plant, the unit flow would be 7 m3/kkg of
HCN. For model plants, treatment levels were based on this unit
flow rate of 7 m3/kkg. However, because the conversion to a
recycle system for this plant would be very energy intensive, an
additional model may have to be developed for treatment costs
usiny the larger flow rate.
Pollutant loading - The three major pollutants in this
subcategory are cyanide, ammonia, and chlorine. Screening
results indicated a cyanide loading of 1.4 kg per kkg of HCN.
This loading is in agreement with a previous document [Ref. 2]
and is used for the models. Screening results also indicated an
ammonia loading of 1.8 kg per kkg of product following ammonia
recovery. Chlorine has been reported at levels of 15 mg/1 and
higher in the effluents from alkaline chlorination.
Treatment technology - Alkaline chlorination was selected
and used for the treatment of hydrogen cyanide waste water. The
formation of chlorinated organics by the usage of this technology
has not been confirmed. Cyanide complexed by metals such as
copper, zinc and cadmium would also be effectively destroyed by
alkaline chlorination.
Chemicals used - At the BPT level of treatment, alkaline
chlorination requires 10 kg of chlorine and 10 kg of lime per kkg
of dCN.
Solids Generated - Little, if any, solids are produced in
the HCN treatment process.
433
-------
17.2 TECHNOLOGY BASED POLLUTION ABATEMENT
17.2.1 Advanced Level Treatment Applications
Control of Significant Observed Priority Pollutants
The only priority pollutant found during field sampling was
cyanide, both oxidizable and in the form of metallic complexes
such as ferro- and ferricynides. Ammonia, which is present as a
nonconventional pollutant, will exert a demand for chlorine used
to oxidize cyanide. This pollutant should be removed by steam
str ipping.
Removal Technologies Available
Cyanide is decomposed readily by oxidation at high pH
levels, forming cyanate as an intermediate product. Further
decomposition into carbon dioxide and nitrogen is possible with
complete oxidation. Alkaline chlorination is widely used in the
electroplating industry to break down metallic cyanide complexes.
Although other oxidation agents such as hydrogen peroxide might
be used, their operating costs are generally not favorable. If
ammonia is present, it increases the cost of chlorination since
it, too, reacts. If ammonia is not to be controlled, ozonation
may prove to be a more cost effective oxidant.
Due to excess chlorine- usage, the discharge from cyanide
destruction is high in chlorine and dechlorination will generally
be needed. (In contrast, this is not usually a problem in the
electroplating industry since there are longer retention periods
and the wastes are more dilute.) Dechlorination can be
accomplished by the use of an aeration basin or the addition of
S02. The use of ozonation would negate the need for
dechlorination.
Selection of Appropriate Technology
BPT
ph
in
adj ustment
the industry.
(Level 1) - Two-stage alkaline chlorination followed by
was chosen, in accordance with prevailing practice
Level .2 - Using the same equipment as in Level 1, excess
is added to insure complete destruction of cyanide and
chloramines. The second-stage effluent is then
chlorine
residual
dechlorinated.
434
-------
Floraras
ei 1 Figure 17-4
el 2 Figure 17-5
pment Functions - In Level 1, the raw waste water is
recin a holding tank equipped with an external pump and
rection system. Caustic soda and chlorine are added and
the contents mixed by means of the recirculation pump.
Fol this first stage alkaline chlorination, the waste water
is r chlorinated in a second tank which is equipped with
aut pH control. The final effluent is neutralized to pH
6-9e discharge. In Level 2, using the same equipment as in
Lev the chlorine feed to the second stage alkaline
chlion system is increased. To remove excess chlorine
befslease, sulfur dioxide is fed by a modified gas
chlor, with oxidation-reduction potential control. As in
Levthe effluent is then adjusted to pH 6 to 9 before
dis.
icals and Handling - Caustic soda solution, chlorine,
sulaxide,* and sulfuric acid are used in the waste treatment
pro Caustic soda and sulfuric acid are common industrial
che which pose no special hazards when handled by
comal corrosion-resistant feeding equipment. Chlorine and
suloxide are received in one-ton containers as compressed
gasand are fed as water solutions by vacuum-controlled
equ designed for the specific chemical. No unusual
chefeeding or handling problems are anticipated, provided
prens are taken to prevent gas leaks and to guard against
cor attack.
ration and Removal p_f Solids - Since few solids are
proin the treatment process, there is no significant sludge
disproblem.
toring Requi rements - Internal process monitoring is
dorgely with automatic sensing and control equipment for
re93 pH and chlorine/sulfur dioxide residuals. Field tests
foride and/or chlorine in the effluent should be made
reg by the operator, and 24-hour composite effluent samples
sho collected and analyzed for cyanide as required in local
or permits.
17.stimated Performance p_f BPT Systems
najor differences in raw waste and treated effluent
quafound at plants producing tiydrogen cyanide by the
And process are due to the following:
435
-------
CAUSTIC SODA
RAW
WASTE WATER
U)
CTi
HOLDING AND 1ST
STAGE ALKALINE
C HIX) RI NATION
-CHLORINE
SECOND STAGE
ALKALINE CHLORINATIOH
ADJUSTMENT
% --- 1
-L,
H)
T-
L
EFFLUENT
Includes flow monitoring, pH monitoring and sampler.
Figure 17-4. Waste water treatment Level 1 for hydrogen cyanide subcategory.
-------
U)
CHLORINE
CAUCTIC
SODA
RAW
WASTE WA'TER
HOLDING AND 1ST STAGE
ALKALINE CHLOR1NATION
ADDITIONAL CHLORINE
SULFUR
t 1
DIOX
IDE f-
-n
'ORP
i
i
^r>ll A
"~1
If
ADJUSTMENT
SECOND STAGE
ALKALINE CHLORINATION
AFFLUENT
Includes flow monitoring, pll monitoring and sampler.
ORP = Oxidation Reduction Potential Control
Figure 17-5. Waste water treatment Level 2 for hydrogen cyanidQ subcategory.
-------
Cooling water recycle - In geographical locations where a
supply of cool water is available, such as at Plant #765, recycle
of the cyanide recovery absorption waste water is not practical
because of the intense energy requirement for refrigeration of
the stream prior to recycle. This once-through contact water is
then treated and discharged.
In locations where a constant supply of cool water is not
available, as at Plant #782, absorption water is refrigerated and
recycled. Recycle of this stream, v/hich is contaminated from
contact with hydrogen cyanide and ammonia, substantially reduces
the waste water volume requiring treatment.
These two different practices in handling process waste
water account for the six-fold variation in unit waste water flow
ooserved in this subcategory.
Treatment Practices - Alkaline chlorination is considered
the most effective treatment for removal of oxidizable or free
cyanide. However, there is concern regarding the formation of
chlorinated organic compounds when organic material is prevalent
in the raw waste water.
At Plant #765, raw wastes result from the manufacture of
inorganic cyanide products. Alkaline chlorination is practiced
and is effective in removing oxidizable cyanide, but is limited
to some extent by the presence of ammonia. Iron cyanide
complexes, less toxic than free or oxidizable cyanides, are not
reduced as effectively.
At Plant #782, raw wastes include wastes from the
manufacture of organic cyanide products. A biological treatment
system is in place to reduce organic and cyanide wastes.
Although effluent pollutant concentrations are higher at this
plant, discharge loads per unit of production are lower due to
the lower waste water flow.
Table 17-9 and 17-10 present verification sampling data from
Plants #782 and #765.
Pollutant Parameters - Analytical procedures for both
oxidizable and total cyanide are questionable as to their
accuracies at the low levels of concentration necessary for
compliance monitoring. A new method for analyzing oxidizable or
free cyanide has been recommended by industry but has not yet
been adopted.
The use of BOD as a pollutant parameter has been questioned
at plants not using biological treatment because the test
requires an acclimated ' seed culture and is highly sensitive to
cyanide and ammonia concentrations.
438
-------
17.9. VERIFICATION SAMPLING OF HYDROGEN CYANIDE PLANT #782
VERIFICATION:
Pollutant
Total Suspended
TSS
Cyanide (Total) ,
Cyanide (Free) ,
BOD
Ammonia, NH3
(Flow =6.25 m3/kkg)
Influent
mg/1 kg/kkg
Solids, no 2.87
CNT 31 0.808
CN 19.0 0.495
1549 40.34
1381 36.05
Effluent Quality
mg/1
74
2.2
1.73
376
5.04
Daily Monitoring Data - Treated Effluent
Parameter
Biochemical
Oxygen Demand,
BOD
Oxidizable
Cyanide CNft
Total Cyanide,
CN,
Armenia, NH-,
Total Suspended
Concentration (mg/1)
Min Avg Max
9.0 39.7 125
0.021 0.112 0.18
0.38 2.33 8.83
2.0 27.1 281
5.0 103 585
Waste Load (kg/kkg)
St.Dev. Min Avg Max
25.7 0.041 2.38 10.2
0.056 0.0014 0.0072 0.013
1.07 0.0025 0.14 1.0
27.4 0.023 1.7 24.1
84.1 0.0088 6.5 50.6
Solids, TSS
439
-------
TABLE 17-10. VERIFICATION SAMPLING OF HYDROGEN CYANIDE PLANT #765
VERIFICATION
Pollutant
(Flow = 57 mVkkg)
Influent
mg/1 kg/kkg
Effluent Quality
mg/1
Total Suspended Solids
TSS*
Cyanide (Total) , CN
Cyanide (Free) , CN
BOD
Ammonia, NH
71
28.4
6.81
6.3
194
6.52
2.61
0.626
0.580
17.8
19
<0.0026
<0.002
<33
124
Average for 2 days only.
Monitoring Data - Treated Effluent
Parameter
1
Concentration (mg/1)
Min Avg Max
Waste Load (kg/kkg)
St.Dev. Min Avg Max
Total Cyanide, 0.78
0 . 01
3.8 9.2
2.56
0.039 0.192 0.46
Oxidizable
Cyanide, CN
0.2 3.27 .319 0.0005 0.01 0.16
Ammonia Nitrogen, 3.86 72 204 46.2
NH3-N
Chemical Oxygen 54.2 320 904 175.4
Demand,COD
Total Organic 15.7 166 512 140
Carbon, TOC
Total Suspended 5.0 35 267 55
Solids,TSS
0.193 3.63 10.2
2.71 15.9 45.2
0.78 8.3 25.6
0.25 1.75 13.4
Results of a 28-day comprehensive test.
440
-------
BPT technology has been specified as alkaline chlorination
of hydrogen cyanide waste waters. Where biological treatment is
applied to the combined process wastes, however, chlorination is
not due to the possibility of chlorinated organics formation.
Base Level Performance Characteristics for BPT Pollutant Removal
Tiie treated effluent quality achievable through
implementation of BPT technology, presented in Tables 17-11 and
17-12, is based primarily on the quality presently achieved at
Plant #765 currently practicing this technology. The two sets of
limitations reflect the two unit flow rates that exist in the
industry.
Ammonia limitations are based on a presumed influent
concentration of 40 mg/1 wich can be achieved with stripping.
Oxidizable cyanide limitations include a variability allowances
to account for the precision of the analytical methods as well as
plant variations.
Base Level
Removal
Performance Characteristics for Priority Pollutant
No priority pollutants, other than cyanide attributable to
hydrogen cyanide production, were found to be of significance.
Pretreatment Applications
BPT technology is applicable for pretreatment of hydrogen
cyanide wastes. Plant #765 is presently discharging to a POTW.
Pollutants such as BOD, TSS and pH are compatible with
municipal treatment systems, and cyanides at low levels are
easily biodegradable. Many states allow pretreatment to 2 mg/1
oxidizable cyanide and 10 mg/1 total cyanide.
Response to Remand Issues
The following major issues, comprising industry's comments
on the original effluent limitations, were reviewed and
addressed :
1. The accuracy and reliability of analytical methods for
measuring cyanide from hydrogen cyanide production. At the
present time, a more reliable method for analysis recommended by
industry is under review. The achievable discharge quality now
recommended as BPT reflects concentrations of cyanide that can be
reliably and accurately analyzed.
441
-------
TABLE 17-11 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Hydrogen Cyanide
Level of Treatment: 1
Waste Water Flow: 50 m3/kkg
Subcategory
Pollutant Performance V
(2)
(mg/1)
Quality Limit
(1) (mg/1)
•T?D
30 day 24 hr
Av e r Max
Emission Limit
(kg/kkg)
30 day
Aver
24 hr
Max
BPT Pollutants:
Total Suspended 35
Solids, TSS
Ammonia, NH3 72
Biochemical Oxygen
Demand , BOD
Cyanide, CN 3.8
Oxidizable 0. 2
Cyanide, CN(A)
2.0
3.0
2.0
2.0
3.0
37.5
24
30
5.0
0.5
75
72
60
10
1.5
1.9
1.2
1.5
0.25
0.025
3.8
3.6
3.0
0.5
0.075
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Average Values
442
-------
TABLE 17-12 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Hydrogen Cyanide
Level of Treatment: 1
Waste Water Flow: 8.9 m3/kkg
Pollutant
BPT Pollutants:
Total Suspended
Solids, TSS
Ammonia, NH3
Subcategory
Performance
(2)
(mg/1)
35
72
Quality Limit
(1) (mg/1)
VFR _ _
30 day 24 hr
Av e r Ma x
2.0 37.5 75
3.0 24 72
Emission
Limit
(kg/kkg)
30 day
Aver
0.33 0
0. 21 0
24 hr
Max
.67
.43
Biochemical Oxygen
Demand , BOD
Cyanide, CN
Oxidizable
Cyanide, CN(A)
—
3.8
0.2
2.0 30 60
2.0 5.0 10
3.0 0.5 1.5
0.27 0
0.044 0
0.004 0
.54
.089
.009
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Average Values
443
-------
2. Process differences in the production of hydrogen
cyanide, particularly the different processes used to separate
ammonia and cyanide. Although the two major production
facilities use different processes for ammonia and cyanide
separation, raw waste loads of ammonia and cyanide resulting from
these processes do not differ significantly.
3. The effect of geographic location of hydrogen cyanide
plants as it relates to cooling water practices. The practice of
not recycling contact absorption water when a supply of cool
water is available has been discussed. Recycling at such
locations would be extremely energy intensive. Achievable
effluent quality with BPT technology has been established with
consideration of the increased volume of waste water when recycle
is not practical.
4. The feasibility and cost-benefit of a 6 - 9 pH
requirement for plants utilizing alkaline chlorination waste
treatment. Costs of neutralization following alkaline
chlorination are included in the cost tables.
5. Contaminated nonprocess wastes such as tank car
washwater and maintenance washdowns. All wasta water sources
were addressed in the discussion of water use and waste water
sources. These sources and their flows were used for the
development of model plant unit waste flows.
6. Deletion from this subcategory of hydrogen cyanide
produced as a by-product of acrylonitrile production. Only the
Andrussow process for hydrogen cyanide production is addressed.
17.2.3 Estimated Performance erf Advanced Level Systems
Identification of Control and Treatment Alternatives Applied to
the Model Plant
Pollutants of major concern in this industry are cyanide and
ammonia. The advanced level technology presented in Section 7
allows for further removal of ammonia and free cyanide by
break-point chlorination. This technology is not applicable to
plants where the potential for the formation of chlorinated
organics exists.
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
^ 17-13 and 17-14 present estimated achievable effluent
quality through the implementation of this advanced technology-
444
-------
TABLE 17-13 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Hydrogen Cyanide
Level of Treatment: 2
Waste Water Flow: 50 m3/kkg
n/tllii-hant* TTfi^^^hll "i •h \7
rOl J. Uucin t. iLtrdL.ciiJj.j.iuy
(mg/l)
BPT Pollutants:
Total Suspended 25
Solids, TSS
Ammonia, NH3 5.0
Biochemical Oxygen
Demand, BOD 30
Cyanide, CN 5.0
Oxidizable
Cyanide, CN(A) 0.2
Total Residual
Chlorine, Cl 0.2
:======================================
Quality Limit Emission Limit
(1) (mg/l) (kg/kkg)
VFR —
30 day 24 hr 30 day 24 hr
Aver Max Aver Max
2.0 37.5 75 1.9 3.8
3.0 5.0 15 0.25 0.75
2.0 30 60 1.5 3.0
2.0 5.0 10 0.25 0.5
3.0 0.2 0.6 0.01 0. 03
2.0 0.2 0.4 0.01 0.02
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
445
-------
TABLE 17-14 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Hydrogen Cyanide
Level of Treatment: 2
Waste Water Flow: 8.9 m3/kkg
(1)
Pnllnt-^nt- Trp^h^hilit~v VF R
(mg/1)
BPT Pollutants:
Total Suspended 25 2.0
Solids, TSS
Ammonia, NH3 5.0 3.0
Biochemical Oxygen
Demand , BOD 30 2.0
Cyanide, CN 5.0 2.0
Oxidizable
Cyanide, CN (A) 0.2 3.0
Total Residual
Chlorine, C12 0.2 2.0
Quality Limit
(mg/1)
30 day 24 hr
Aver Max
37.5 75
5.0 15
30 60
5.0 10
0.2 0.6
0.2 0.4
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
0.33 0.67
0.044 0.014
0.27 0.53
0.044 0.14
0.0018 0.005
0.0018 0.0036
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
446
-------
New
Source Performance Standards
Examination of current control and treatment practices has
led to the conclusion that NSPS for new hydrogen cyanide plants
should be equivalent to BPT treatment technology with appropriate
recycle of absorption water to minimize process waste volumes.
17.2.4 Cost Estimates
Discussion
The cost estimates for three models at different production
and levels of treatment are presented in Tables 17-15, 17-16 and
17-17. Annual treatment costs as a function of production is
shown graphically in Figure 17-6. Treatment cost per metric ton
of product is shown in Figure 17-7.
Table 17-18 gives a summary of the unit cost distribution
between amortization and operation and maintenance cost
components at various production and levels of treatment.
Summary
Cost estimates developed for the first level of treatment
indicate that chemical cost has the most significant impact on
the total annual costs. At the second level of treatment,
additional chemical cost is the single most important factor in
the annual costs.
447
-------
TABLE 17-15. MODEL PLANT TREATMENT COSTS
Subcategory HYDROGEN CYANIDE Type of Regulation BAT
Production 31,800 metric tons per year ( 35,059 tons per year)
90 metric tons per day ( 100 tons per day )
Waste water flow 640 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $15,750 $5,100
Equipment in place,
including piping,
fittings, electrical
work and controls 150,700 41,500
Monitoring equipment
in place 9,000
Engineering design
and inspection 35,090 9,320
Incidentals, overhead,
fees, contingencies... 35,090 9,320
Land 1,200
TOTAL INVESTMENT COST $246,830 $65,240
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $84,000
Energy 2,750 1,900
Chemicals 199,000 116,000
Maintenance 24,563 6,524
Taxes and insurance... 7,404 1,957
Residual waste
d isposal
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $332,717 $133,881
C. AMORTIZATION OF
INVESTMENT COST $39,964 $10,614
TOTAL ANNUAL COST $372,681 $144,495
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
448
-------
TABLE 17-16. MODEL PLANT TREATMENT COSTS
Type of Regulation BAT
Subcategory HYDROGEN CYANIDE
Production 50,900 metric tons per year ( 56,117 tons per year)
145 metric tons per day ( 160 tons per day )
Waste water flow 1020 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $19,250 $5,500
Equipment in place,
including piping,
fittings, electrical
work and controls 224,750 46,500
Monitoring equipment
in place 9,000
Engineering design
and inspection 50,600 10,400
Inc identals, overhead,
fees, contingencies... 50,600 10,400
Land 1,200
TOTAL INVESTMENT COST $355,400 $72,800
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $84,000
Energy 3,000 2,600
Chemicals 318,000 186,000
Maintenance 35,420 7,280
Taxes and insurance... 10,662 2,184
Residual waste
disposal
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $466,082 $205,564
C. AMORTIZATION OF
INVESTMENT COST $57,628 $11,844
TOTAL ANNUAL COST
$523,710
$217,408
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost,
449
-------
TABLE 17-17. MODEL PLANT TREATMENT COSTS
Subcategory HYDROGEN CYANIDE Type of Regulation BAT
Production 63,600 metric tons per year ( 70,119 tons par year)
181 metric tons per day ( 200 tons per day )
Waste water flow 1280 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $24,250 $5,700
Equipment in place,
including piping,
fittings, electrical
work and controls 266,000 52,500
Monitoring equipment
in place 9,000
Engineering design
and inspection 59,850 11,640
Incidentals, overhead,
fees, contingencies... 59,850 11,640
Land 1,200
TOTAL INVESTMENT COST $420,150 $81,480
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $84,000
Energy 3,700 3,400
Chemicals 399,000 232,000
Maintenance 41,895 8,148
Taxes and insurance... 12,604 2,444
Residual waste
disposal
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $556,199 $253,492
C. AMORTIZATION OF
INVESTMENT COST $68,163 $13,256
TOTAL ANNUAL COST $624,362 $266,748
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
450
-------
o
o
u •
§
1
(i
(t
/
1
T
/
/
/
X
/
>
r
/
X
f
/
/
/
/
/
/\
/
/
'
/I
r
(
(•)
X*.
/
X
/
x1
/
s
s
/
/
/
/
/
/
(a
/
^s
;
)
JU
I
E1
,E
/•E
VI]
L
L
fz
#1
30 40 50 "" 60 70 80
HCN PRODUCTION, METRIC TONS/YEAR X 1000
Figure 17-6. Annual treatment cost as a function of production for the
Hydrogen Cyanide Subcategory
451
-------
16
15
14
13
12
11
10
•w-
§
TT
I I I
i i Ki
i i
I i
30 40 50 60 70 80
HCN PRODUCTION, METRIC TONS/YEAR X 1000
Figure 17-7. Annual unit treatment cost as a function of
production for the Hydrogen Cyanide Subcategory
452
-------
TABLE 17-18 MODEL PLANT TREATMENT COSTS
Subcategory HYDROGEN CYANIDE
Type of Regulation BAT
Annual Treatment Costs ($/kkg)
LEVEL OF TREATMENT
PRODUCTION FLOW FIRST SECOND THIRD FOURTH
(kkg/yr) (m3/day) $ $ $ $
Annual Operation
and Maintenance
Annual
Amortization
Total Cost
31,800
50,900
63,600
640
1,020
1,280
31,800
50,900
63,600
31,800
50,900
63,600
640
1,020
1,280
640
1,020
1,280
10.46
9.16
8.75
1.26
1.13
1.07
11.72
10.29
9.82
4.21
4.04
3.99
0.33
0.23
0.21
4.54
4.27
4.19
Not Applicable
453
-------
SECTION 18
SODIUM DICHROMATE INDUSTRY
18.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
18.1.1 Industry Profile a_nd Analytical Results
Most of the sodium dichromate produced is used in the
chromic acid and pigment industries. It is used for leather
tanning, and raetal treatment as well as a corrosion inhibitor.
The industry profile data for this
Table 18-1, and the summary of existing
Table 18-2.
subcategory
regulations
is given
is given
in
in
Priority pollutants found in significant
waste during sampling were as follows:
levels in the raw
Maximum Concentration
Pollutant
Sc reening
Observed (ug/1)
Verification
(2 Plants)
Chromium
Nickel
Zinc
Copper
Silver
Selenium
252,
12,
070
500
544
35
<.05
<5
312,
1,
1,
000
260
230
240
228*
22*
* Found at one plant only
** Non contact cooling water at one plant only
A summary of daily and unit product raw waste loads for all
plants sampled can be found in Table 18-3. Individual plant raw
waste loads per unit product found in sampling can be found in
Table 18-4.
Based on the total annual production of this subcategory and
the average waste load generated per unit product, the estimated
total pollutant raw waste loads generated each year for this
subcategory are as follows:
454
-------
TABLE 18-1
SUBCAIEGORY PROFILE DATA SUMMARY
SUBGATEGORY
SODIUM DICHROMATE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
140,000 kkg/year
136,500 kkg/year
5
3
112,000 kkg/year
82 percent
20,700 kkg/year
66,800 kkg/year
37,300 kkg/year
24,800 kkg/year
77 percent
7 years
28 years
455 cubic meters/day
720 cubic meters/day
4 cubic meters/kkg
8 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
455
-------
WmR 18-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SOBCMEGORY Sodium Dichromate
SUBPAKT Q (40CFR 415.170, 3/12/74)
STANDARDS
BPCTCA BATEA* NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
Na,Cr_0_ TSS 0.44 0.22 ^ J^fS?*96
221 or pwwp
Cr+6 0.009 0.0005 N° dischar9e
of pwwp
Cr(T) 0.0088 0.0044 N? dlschar9e
or pwwp
0.30 0.15
0.009 0.0005
0.0088 0.0044
* Section 415.173 was remanded and is presently reserved (41 FR 51601,
November 23, 1976) .
"wax, = Maximum of any one day.
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants.
456
-------
TABLE 18-3.
SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
SUHCATEGOHY
1 vj| lutanl.
Priority
Chromium, Cr
Copper, Cu
Nickel, Ni
Silver, Ag
Zinc, Zn
Selenium, Se
Arsenic, As
Conventional
TSS
Hex. Chro-
SODIUM DICHROMATE
Loadings
kg/day
Minimum Average Maximum Minimum
82.1 132 181 0.95
0.0091 0.32 0.92 0.00005
0.27 4.26 8.98 0.006
0.058
0.067 0.22 3.91 0.0009
0.23
0.005
26603 131066 235646 140
27.5 1212 3105 0.466
kg/kkg
Average
1.17
0.0046
0.034
0.0009
0.002
0.003
0.00008
2068
15.7
No. of Plants
Maximum Averaged
1.39 2
0.013 3
0.049 3
1
0.003 3
1
1
3997
43.9
mium, Cr
+6
-------
18-4. PRIORITY POLLUTANT RAW WASTE LOADS (in kg/kkg of Product)
SODIUM DICHRCMATE
SUBCATEGORY
.
POLLUTANT
Chromium, Cr
Copper, Cu
Lead, Pb
Nickel, Ni
Zinc, Zn
Silver, Ag
Selenium, Se
Arsenic, As
#493
0.95
0.00005
0.047
0.002
PLANT
#398
0.013
0.00014
0.049
0.0009
0.003
#376
1.39
0.0008
0.0002
0.006
0.003
0.00099
0.0008
458
-------
Pollutant
Waste Load (kg/year)
Chromium
LMickel
Zinc
Copper
TSS
Cr + 6
160000
4600
270
630
280,000,000
2,100,000
18.1.2 Process Waste Sources and Waste Wat, er Treatment Data
General Process Description
The starting materials
dichromate are chromite ore,
above materials are reacted,
reacted with sulfuric acid
reactions are given as:
for the preparation of sodium
limestone and soda ash. When the
sodium chromate is formed which is
to produce sodium dichromate. The
4FeCr204
8Na2C03
702 = 8Na2Cr04
2Fe203
8C02
(i;
2>Ma2Cr04
H2S04 = Na2Cr207
H20
Na2S04
Chromite ore is a chromium iron oxide containing ferrous
chromite (FeCr204 or FeOCr203). Small amounts of aluminum, silica
and magnesia are present. For the preparation of sodium chromate
and finally, sodium dichromate, high grade chromite ores are used
containing approximately 50 percent Cr203. These ores are
imported from South Africa.
At the plant site, the ore is ground to a fine powder, mixed
with soda ash and calcined in rotary kilns at 1100 to 1150
degrees C. The reacted product is leached with hot water in a
leachate tank. The thickener underflow is filtered and the
filtrate recycled to the leachate tank or thickener. The solid
filter cake is dried in rotary kilns. The aluminum present in
the thickener overflow is hydrolyzed and removed from the
chromate solution as precipitated aluminum hydrate in slurry
form. The solution is centrifuged and the centrate is evaporated,
to give a concentrated solution of sodium chromate, which is
reacted with sulfuric acid to give sodium dichromate and sodium
sulfate. Sodium sulfate crystallizes as anhydrous sodiun sulfate
from the boiling solution, and the crystals are removed by
filtration. The filtrate is concentrated in multiple effect
evaporators. The residual sodium sulfates separate out as solids
from each of the evaporators while the hot concentrated solution
of sodium dichromate from the last effect of the evaporator i3
459
-------
fed to a water-cooled crystal!izer. Sodium dichromate
crystallizes out and is centrifuged. The centrate, or mother
liquor, is returned to the evaporator. The sodium dichromate
crystals separated in the centrifuge are dried in a rotary drum
dryer and then packaged for sale or stored for use. Figure 18-1
presents a generalized flow diagram for the production of sodium
dichr ornate.
Water Use and Waste Source Inventories
Water Use - Water is used for noncontact cooling, in
leaching, for scrubbing vent gases and for process steam for
heating. Water use information provided in 308 Questionnaires is
given in Table 18-5. It is possible that the figures given in
the 308 Questionnaires may be the amount going to each unit
operation and not the amount added as makeup water. The
quantities seem unusually high for an industry practicing
extensive recycling of water, as this one does.
Waste Sources -
A. Spent ore: Tiie unreacted ore is removed from the process
as a sludge. The solids contain chromium and other impurities
originally present in the ore. The waste is disposed as a solid
waste in a landfill or is slurried with water and sent to the
treatment facility.
B. Noncontact cooling water and cooling tower blowdown: The
noncontact cooling water is either used on a once-through basis
and discharged or is recycled and the blowdown discharged to the
treatment facility- In addition to dissolved sulfate and
chloride, it may contain chromates.
C. Boiler blowdown: The steam used for heating is
recovered as condensate, while the boiler blowdown is discharged
to the treatment facility. It may become contaminated with
chromium escaping from the process area and hence snould be sent
to the waste water treatment facility for treatment.
The majority of aqueous streams resulting from the
manufacture of sodium dichromate are recycled. Streams recycled
include compensates from product evaporation and drying; product
recovery filtrates; air" pollution control scrubber effluents
from product drying, leaching and roasting kilns; filter wash
waters; and equipment and process area washdowns. At two plants
the v/aste water, consisting of boiler and noncontact cooling
tower, is used to slurry the spent ore residue to the waste >vater
treatment facility. At one plant, the only waste water resulting
from process operations is the noncontact cooling water, which is
used on a once-through basis.
460
-------
TO SALES OR USE
SODA ASH
RECYCLE •
WATER
FROM
PROCESS
COOLING TOWER AND —
BOILER
SLOWDOWN TO WASTE
TO SALES
TO SALES
Figure 18-1. General process diagram for productions of sodium dichromate.
-------
18-5.
Source
WATER USAGE IN SODIUM BICHROMATE SUBCATEGORY
Water usage at plants m /kkg of
Non-contact cooling
Direct process contact
Indirect process contact
(pumps, seals, leaks and
spills)
Maintenance, e.g.
cleaning and work area
washdown
Air pollution control
Non-contact ancillary
uses
Plant #398
255
5.7
0.9
0.5
2.5
0.5
Plant #376
11.39
NA
NA
NA
NA
NA
Plant #493
5.7
2.85
0.2
0.2
1.0
3.12
NA = Not Available
462
-------
Control and Treatment Practices
Three sodium dichrornate plants were visited and the waste
water streams sampled. Plant #493 was sampled in the screening
phase and Plants £376 and #398 were sampled in the verification
phase.
At Plant #493, the waste water going to the treatment
facility includes the boiler and cooling tower blowdown and a
small volume of effluent from a scrubber on a by-product sodium
sulfate operation. The total waste includes the spent ore
residue, wtiich is also sent to the treatment facility. At the
treatment facility, the alkaline waste waters are reacted with
imported acidic industrial waste at an elevated temperature in a
reactor. The chromium is precipitated during the reaction. The
reacted waste is sent to clarifiers via holding tanks. In the
clarifiers, large quantities of water are used to wash the
precipitated solids in a counter-current fashion. The final
clarifier overflow, which is the treated effluent, is filtered
and discharged and the clarifier underflow is disposed of in a
quarry. Figure 18-2 is a block diagram of the treatment process
and indicates which streams were sampled. Table 18-6 gives the
flow data and pollutant emissions of the streams sampled.
At Plant #376, sodium sulfide is used for simultaneous
chromate reduction and precipitation. The waste waters at this
plant are segregated into two streams. One stream consists of
the cooling tower and boiler blowdown and is used for slurrying
the spent ore residue to the treatment facility. The second
waste stream consists of storrnwater runoff from both the solids
disposal areas and the production areas. The first waste water
stream is mixed with sodium sulfide during transporation and sent
to a diked containment and settling pond system. The sulfide
reduces the hexavalent chromium to trivalent chromium, which in
turn is precipitated as chromium hydroxide. The solids are
settled in the pond, and the overflow from the ponds is mixed
with the second waste stream and reacted with sufficient alkaline
sodium sulfide to reduce the chromate and precipitate chromium
hydroxide. The reacted solution is sent to a settling pond where
the precipitated and other suspended solids are settled and the
overflow discharged. A simplified flow diagram of the waste
water treatment process is given in Figure 18-3. Table 18-7
gives the flow data and pollutant emissions for the streams
sampled.
At Plant #398, the only effluent produced is the noncontact
cooling water. The noncontact cooling water is used on a once-
through basis and is discharged without treatment through two
out-falls. The solid waste residuals from the leaching process
are trucked to a state-licensed hazardous waste landfill area.
The amount of solid waste residue disposed of is approximately
290 kg/kkg of product. Table 18-8 gives the unit flow data and
463
-------
RAW WASTE WATER
IMPORTED ACID
INDUSTRIAL WASTE
CT>
WATER
e
Waste streams sampled.
TREATED EFFLUENT
SLUDGE TO
LAND DISPOSAL
Figure 18-2.
General waste water treatment process flow diagram at Plant 1493 showing the
sampling points. (Sodium Dichromate Manufacture)
-------
TABLE 18-6. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT #493 PRODUCING SODIUM DICHRCMATE
Stream No. Waste Stream Unit Flow TSS Load
Description kg/kkg
of Na2Cr207 of
Cr Load Chromium
kg/kkg
road
of
of
1
2
Raw Waste
Water
4.95
Treated Efflu- 28.91
ent
Residue Slurry 2.13
183
0.013
185
3.5
0.00004
0.0004
1.25
0.022
3.93
465
-------
WkSTE
MUD
SLURRY
e-
Ch
e
SODIUM SULFIDE
SETTLING AND
DEWATERIN3
IANDFILL AREAS
Waste streams sanpled.
TREATED EFFLUENT
Figure 18-3. General waste water treatment process flow diagram at Plant 1376
showing the sampling points. (Sodium Dichromate Manufacture)
-------
TABLE 18-7. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT #376 PRODUCING SODIUM DICHRCMATE
Stream No. Waste Stream Unit Flow TSS Load Cr Load Chromium
m /kkg kg/kkg kg/kkg Load
of Na2Cr207 of Na2Cr207 of Na2Cr207 kg/kkg
of Na2Cr20?
1 Mud Slurry 7.68 3988 0.407 1.041
Waste
2 Primary Pond 7.68 0.591 - 0.808
Effluent
3 Surface Runoff 4.16 0.621 0.057 0.55
4 Effluent 4.16 7.942 - 0.77
467
-------
18-8. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLE WASTE
STREAMS FOR PLANT #398 PRODUCING SODIUM DICHROMATE
Stream No. Waste Stream Unit Flow TSS Lead Cr Load Chromium
Description ^ kg/kkg kg/kkg
0fNa2Cr207 of Na^O, of Na^O,
1 Non-contact 71 - 6.72 0.013
cooling water
2 Non-contact 206 - 14.28 0.018
cooling water
468
-------
pollutant emissions for the process effluent.
Model Plant and BPT Treatment System Specifications
Model plant specifications were selected for the purpose of cost
estimation. The rationale for the selection of model plant
characteristics is as follows:
Production - Five industrial plants produce sodium
dichromate at a total production rate of approximately 140,000
kkg/year. Production and waste water flow data, from which model
plant characteristics are derived, are on file for three plants
which produce a total of 112,000 kkg/year; that is approximately
80 percent of the United States production. For waste water
treatment cost estimates, three production levels were selected.
These are 20,000 kkg/year, 50,000 kkg/year and 70,000 kky/year.
Waste Water Flow - Unit waste flows for the two plants
treating their waste waters are approximately 5 and 12ra3/kkg of
product. For the model plant, 7rn3/kkg of sodium dichromate was
used as the waste water flow.
Pollutant Load ing - For the model plant, it is assumed that
the spent ore resTcTues are slurried and transported to the
treatment facility, since this is the prevalent practice at two
plants. The spent ore waste-generated residue at Plant 1969 is
290 kg/kkg of Na2Cr207. The hexavalent chromium loading in the
waste water varies from 0.5 to 14 kg/kkg of Na2Cr207. Pollutant
loadings used for the model plants are suspended solids (spent
ore residue) at 290 kg/kkg Na2Cr207 produced, and hexavalent
chromium at 5 kg/kkg.
Chemicals required - To reduce Cr+6 to Cr + 3, a sodium
bisulfide dosage of 158 mg/1 is needed, but to allow for reaction
with other metals, a model dosage of 200 mg/1 was used. This is
equivalent to 1.4 kg/kkg of product in a unit flow of 7m3/kkg.
To raise the pH to 9.5, 100 mg/1 of lime is needed, equivalent to
0.7 kg/kkg of product. For final neutralization, HCl is used in
the amount of 10% of the lime dosage.
Solids generated - Total dry solids produced are 0.36 kg/kkg
of sodium dichromate.
469
-------
18.2 TECHNOLOGY BASED POLLUTION ABATEMENT
18.2.1 Advanced Level Treatment Applications
Control of Significant Observed Priority Pollutants
Priority pollutants found in significant amounts are the
primary pollutant, hexavalent chromium, and the common heavy
metals often present as impurities in the chromium ore, notably
zinc and nickel. In controlling these metals by the processes
chosen for the treatment models, incidental removal of other
trace heavy metals will also be achieved.
Removal Technologies Available
Alkaline precipitation or reaction with sulfide will
separate nickel and zinc from solution. Hexavalent chromium must
be reduced to its trivalent form before it can be precipitated by
alkaline substances. Although ion exchange or xanthates can
remove metals from clarified solutions they are inappropriate for
treating raw waste slurries from this industry.
Technologies to be Applied at Each Level
BPT (Level !_)_ - The system utilizes sodium bisulfide added
to the raw wastes to reduce hexavalent chromium to its trivalent
form and to partially precipitate some of the metals as metallic
sulfides, along with inert ore solids in a first-stage lagoon.
The lagoon effluent is then subjected to alkaline precipitation
of trivalent chromium, followed by solids separation in a
clarifier and by ph adjustment of the overflow before discharge.
Level 2_ - Dual-media filtration is added to achieve a higher
level of suspended solids removal, including metallic hydroxides
and sulfides which may have passed through the clarifier. The
effluent is adjusted to a pH range of 6 to 9 as in Level 1.
These technologies are uniquely appropriate for wastes of the
sodium dichromate industry because the sodim bisulfide
?retreatment performs the dual function of converting hexavalent
chromium to a potentially settleable form, as well as reacting
with other heavy metals to form insoluble metallic sulfides.
470
-------
Flow diagrams
Level 1 Figure 18-4
Level 2 Figure 18-5
Equipment Functions - The raw waste flows into an equalizing
lagoon wheretFeinfluent flows are measured by a magnetic flow
meter which controls application of sodium bisulfide solution
into the influent pipeline. Hexavalent chromium is converted to
the less toxic trivalent form and together with trace metal
sulfides and inert solids passes to the first-stage lagoon. A
second application of sodium bisulfide is made in the lagoon
outflow, and lime is added to precipitate trivalent chromium and
residual trace metals prior to clarification. In Level 1 the
clarifier effluent is adjusted to pi-1 6 to 9 and released. In tiie
Level 2 system a dual media filter is added to remove additional
suspended material from the overflow. Clarifier underflow and
filter backwash are returned to the equalizing lagoon influent,
to be settled in the la-goon.
Chemicals and Hand1ing - Sodium bisulfide, lime, and
hydrochloricacid are used in the treatment process. The first
application of sodium bisulfide is made into the influent
pipeline in proportion to flow, minimizing the release of
hydrogen sulfide at times when the influent pH may be low. The
second application of sodium bisulfide is also into a closed
pipeline to ensure adequate mixing with the settled lagoon
effluent. Lime slurry is fed through conventional equipment ahead
of the clarifier. Hydrochloric acid is used (instead of sulfuric
acid) to minimize the formation of gypsum scale which could
result from heavy use of lime followed by sulfuric acid. There
do not appear to be unusual hazards involved in the handling of
chemicals for the proposed treatment.
Sepa rat ion a_n_d_ Pi sposal ojf So 1 ids - As a basis for
estimating model" pi a nt c~ost~s, influent suspended solids,
metallic hydroxide and sulfide precipitates, and filter backwash
are returned to or left in the influent lagoons(s) . As each
lagoon becomes filled with solids it is replaced by another, on a
ten-year cycle. Liquid is decanted from each filled lagoon and
the solid material needs to be disposed of in either an on-site
or an off-site chemical landfill.
Monito ring Requi rements - Internal process monitoring should
include routine testing to maintain reducing conditions and a pH
above 7 in the influent lagoons, and simple field determination
of pH, to assure that the optimum level is reached for
precipitation of chromic hydroxide. Routine testing of the
effluent should also be performed at the site to show that
hexavalent chromium is being consistently reduced to trivalent
471
-------
SODIUM SODIUM P|LIME
BISULFIDE BISULFIDE U
r-Ql
i :
i
RAW |
WASTE i
* r~]
/^v MPH ADJUSTMENT
. Q t---^) v
i
MAGNETIC 1
METER |
1
1
_^\ LAGOON /—*~\
•
\ /
1 — *\ LAGOON / — «J
1 ¥"""!
/*^v
! ! ©
U L T
^ i ! ^Q i
MIX
TANK k. y
N/CLARIFIER
1
| 1
L-_. ... — trv« 1
Includes flow monitoring, pH monitoring and sampler.
Figure 18~4. Waste water treatment Level 1 for sodium dichronate subcategory.
-------
BACKWASH
r
1 f=\ LIME
SODIUM . SODIUM n
BISULFI
r£l
I
1 j
RAW I
WASTE J.^
DEI BISULFIDE^y
1 p L— .@
f | ,_A LAGOON /_^ Y 1 !
1
^
»U |
MAGNET1C i
METER '
1
|
1
1
L..-A LAGOON / ^1
1
L 9 I
r ' u" q
JL i
MIX
TANK V )
*
A \^S^
pv pH ADJUSTMENT
F~ ~\
JL.
fpK)
vjy
^ ! . „ .
n ntr^ "u " ••"
*
SUMP FILTER EFFLUENT
X/CLAIUFIER
1
U)
_1
Includes flow monitoring, pH monitoring and sampler.
Figure 18-5. Waste water treatment Level 2 for sodium dicliromate sutcategory.
-------
chromium and that total chromium in the final effluent does not
exceed the allowable limit. Periodic composite effluent samples
should be analyzed for total chromium by the atomic absorption
method, for official reporting purposes.
18.2.2 Estimated Performance o_f BPT Systems
Extensive recycle and reuse of process contact waste water
limit effluent generation at sodium dichromate plants. At two
facilities, cooling water blowdown streams are used to slurry
spent ore residues and the resultant waste stream is treated for
the removal of chromium prior to discharge. At the remaining
plant, ore residues are removed as a solid waste and only once
through noncontact cooling water is discharged.
Table 18-9 summarizes effluent control and treatment
technologies at each plant and indicates the characteristics of
the resulting effluents. It can be noted that the cooling water
at plant 1398 is contaminated with chromium. Low concentrations
and high discharge volume account for the high chromium effluent
loads.
Raw waste priority pollutants found in excess of cutoff
limits at these three facilities were presented in Section 6. By
use of the compressed scale method for selecting pollutants which
might require regulation, chromium, nickel and zinc were
identified. Table 18-10 presents priority pollutant effluent
loads found during sampling at two of the three facilities.
BPT technology has been specified as reduction of hexavalent
chromium, and hydroxide precipitation of chromium with final
settling to remove suspended solids.
Base Level Performance Characteristics for BPT Pollutant Removal
Pollutant reductions achievable by application of BPT or
Level 1 technology are presented in Table 18-11.
Base Level Performance Characteristics for Priority Pollutant
Removal
Table 18-11 also presents effluent quality achievable
through the application of BPT or Level 1 technology for the
reduction of priority pollutants.
Pretreatment Applications
No sodium dichromate plant presently discharges waste to a
474
-------
TABLE 18-9. EFFLUENT CONTROL AND TREATMENT PRACTICES AND ACHIEVEMENTS
AT SODIUM DICHROMATE PLANTS *
Plant
#398
Control and
Treatment Practice
Once through
cooling water,
disposal of ore
residue as solid,
no treatment of
cooling water
discharge
Effluent Waste Load kg/kkg
CrT Cr+6 TSS
pH Avg. Max. Avg. Max. Avg. Max.
0.0079, 0.034
6.6
to
8.5
#493 Recirculate cooling 0.00038 0.0049 0.00018 0.1 0.3
water, slurry ore
residue, treat all 6'.3
wastes with.pickle to
liquor, counter- 8.3
current solids wash,
clarify and filter
effluent
#376 Recirculate cooling 0.00058 0.0017 0.00058 0.047 0.69
water, slurry or
residue, treat all
wastewater with
sodium sulfide,
remove solids in
settling ponds
* See Reference 3.
475
-------
18-10. VERIFICATION SAMPLING OF SODIUM DICHPOMATE PLANTS
Pollutant
Plant #398
Treated Effluent
kg/kkg
Plant #493
Raw Waste Treated Effluent
kg/kkg mg/1 kg/kkg
•total Suspended
Solids, TSS
Chromium VI, Cr
Chromium, Cr
Nickel, Ni
Zinc, Zn
Copper, Cu
Flow (m3/kkg)
2.05
43.9
**
0.049
0.0009
0.013
584
140
2.64
0.95
0.047
0.002
0.00005
3.8
2
0.004
2.5
0.090
0.110
0.016
0.0075
0.000016
0.0094
0.00034
0.00041
0.00006
No treatment, only cooling water outfalls,
*
Less than supply water of 0.495 mg/1.
476
-------
TABLE 18-11 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Sodium Bichromate
Level of Treatment: 1
Waste Water Flow: 7 m3/kkg
Pollutant
Subcategory
Per formance
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Av e r Max
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
BPT Pollutants:
Total Suspended 12
Solids, TSS
2.0
35
70 0.26 0.52
Total Chromium, Cr 0.05 2.0 0.5 1.0 0.0035 0.007
Hexavalent
Chromium, Cr+6
Proposed Priority
Pollutants
Nickel, Ni
Zinc, Zn
(2)
0.01 2.0
(2)
0.2 2.0
(2)
0.1 2.0
0. 1
0.5
0.2 0.0008 0.0016
1.0 0.0035. 0.007
0.5 1.0 0.0035 0.007
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Verification Sampling
477
-------
POTW. Future discharges can readily be treated to BPT levels and
this standard should be adopted for pre-treatment requirements.
18.2.3 Estimated Performance p_f Advanced Leve^l Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
Necessary to the achievement of good effluent quality after
precipitation of heavy metals, is the control of suspended
solids. In the Sodium Bichromate Subcategory, it can be assumed
that chromium is a significant constituent in the suspended
solids discharged. For this reason, only one advanced treatment
alternative, addition of a filtration unit for solids control,
has been recomraended.
Table 18-12 presents the estimated achievable effluent
quality through the implementation of this advanced technology.
New Source Applications
Examination of current control and treatment practices in
this subcategory has led to the conclusion that NSPS for sodium
dichrornate plants should represent the application of the
advanced recycle technology currently practiced at one facility.
Response to Remand Issues
The zero discharge requirement originally promulgated as BAT
for sodium dichromate production was remanded on the basis of
inadequate technical and economic justification for the
evaporative technology required to eliminate discharge- A
control and treatment alternative, which allows waste water
discharge, has been identified and the performance levels
achievable have been demonstrated at one facility.
18.2.4 Cost Estimates
Discussion
The cost estimates of three aiodels having different
production levels are presented in Tables 18-13, 18-14, and
18-15. Annual treatment costs as a function of production are
shown graphically in Figure 18-6. Treatment cost per metric ton
°f product is shown in Figure 18-7.
478
-------
TABLE 18-12 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Sodium Bichromate
Level of Treatment: 2
Waste Water Flow: 7 m3/kkg
lutant
ility
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Aver Max
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
BPT Pollutants;
Total Suspended
Solids, TSS
Hexavalent
Chromium, Cr+6
Proposed Priority
15
Total Chromium, Cr 0.3
0.1
2.0 15
2.0
2. 0
0. 2
0. 1
30 0.10 0.21
0.4 0.0014 0.0028
0.2 0.0008 0.0016
Pollutants
Nickel, Ni
Zinc , Zn
0.
0.
1
4
2.0 0.1
2.0 0.4
0.
0.
2
8
0.
0.
0007
003
0.0014
0.006
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
479
-------
TABLE 18-13. MODEL PLANT TREATMENT COSTS
Subcategory SODILM BICHROMATE Type of Regulation BAT
Production 20,000 metric tons per year ( 22,050 tons per year)
57 metric tons per day ( 63 tons per day )
Waste water flow 400 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $615,250 $4,700
Equipment in place,
including piping,
fittings, electrical
work and controls 168,500 33,200
Monitoring equipment
in place 9,000
Engineering design
and inspection 158,550 7,580
Inc idental s, overhead,
fees, contingencies... 158,550 7,580
Land 156,000
TOTAL INVESTMENT COST $1,265,850 $53,060
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $56,000 $14,000
Energy 2,500 600
Chemicals 17,000
Maintenance 110,985 5,306
Taxes and insurance... 37,975 1,591
Residual waste
disposal
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $239,460 $28,997
C. AMORTIZATION OF
INVESTMENT COST $180,572 $8,632
TOTAL ANNUAL COST $420,032 $37,629
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
480
-------
TABLE 18-14. MOEEL PLANT TREATMENT COSTS
Type of Regulation BAT
Subcategory SODIUM BICHROMATE
Production 50,000 metric tons per year ( 55,125 tons par year)
142 metric tons per day ( 157 tons per day )
Waste water .flow 1000 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $1,375,800 $8,600
Equipment in place,
including piping,
fittings, electrical
work and controls 302,500 80,500
Monitoring equipment
in place 7,000
Engineering design
and inspection 337,060 17,820
Incidentals, overhead,
fees, contingencies... 337,060 17,820
Land 252,000
TOTAL INVESTMENT COST $2,611,420 $124,740
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $56,000 $14,000
Energy 2,800 1,000
Chemicals 42,000
Maintenance 235,942 12,474
Taxes and insurance... 78,342 3,742
Residual waste
disposal
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $430,084 $38,716
C. AMORTIZATION OF
INVESTMENT COST $383,877 $20,295
TOTAL ANNUAL COST $813,961 $59,011
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
481
-------
TABLE 18-15. MODEL PLANT TREATMENT COSTS
Subcategory SODIUM BICHROMATE Type of Regulation BAT
Production 70,000 metric tons per year ( 77,175 tons per year)
200 metric tons per day ( 220 tons per day )
Waste water flow 1400 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $1,742,950 $12,200
Equipment in place,
including piping,
fittings, electrical
work and controls 390,500 91,500
Monitoring equipment
in place 9,000
Engineering design
and inspection 428,490 20,740
Incidentals, overhead,
fees, contingencies... 428,490 20,740
Land 324,000
TOTAL INVESTMENT COST $3,323,430 $145,180
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $56,000 $14,000
Energy 2,800 1,000
Chemicals 58,000
Maintenance 299,943 14,518
Taxes and insurance... 99,702 4,355
Residual waste
disposal
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $531,445 $41,373
C. AMORTIZATION OF
INVESTMENT COST $488,007 $23,620
TOTAL ANNUAL COST $1,019,452 $64,993
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
482
-------
11
10
i i
j®.
o
o
o
o
o
X
EH
§
ll
/ A
A
w
A \ i
I/
Z
a
/i / i
4l£
ZO 30 40 50 60 70
PRODUCTION, METRIC TONS/YEAR X 1000
Figure 18-6. Relationship of annual treatment cost to production
for the Sodium Bichromate Subcategory
483
-------
22
21
20
19
18
17
16
15
14
\
V
\
I i
J I
I !
n
20 30 40 50 60
PRODUCTION, METRIC TONS/YEAR X 1000
TO
Figure 18-7- Relationship of annual unit treatment cost to production
for the Sodium Dichromate Subcategory
484
-------
Table 18-16 gives a summary of the unit cost distribution
between amortization and the operation and maintenance cost
components at various production and levels of treatment.
Summary
At the first level of treatment, investment costs are high
because sludge lagoons costs are provided for a ten year period.
Therefore, amortization is the major portion of the total annual
costs. In place of annual cost for the residual waste (sludge)
disposal, a large investment in land is shown. At the second
level of treatment, labor and amortization have significant
impact on the additional annual costs.
485
-------
TABLE 18-16 MODEL PLANT TREATMENT COSTS
Subcategory SODIUM DICHROMATE
Type of Regulation BAT
Annual Treatment Costs ($/kkg)
LEVEL OF TREATMENT
PRODUCTION FLOW FIRST SECOND THIRD FOURTH
(kkg/yr) (m3/day) $ $ $ $
Annual Operation
and Maintenance
Annual
Amortization
Total Cost
20,000
50,000
70,000
400
1,000
1,400
11.97
8.60
7.59
1.45
0.77
0.59
20,000
50,000
70,000
20,000
50,000
70,000
400
1,000
1,400
400
1,000
1,400
9.03
7.68
6.97
21.00
16.28
14.56
0.43
0.41
0.34
1.88
1.18
0.93
Not Applicable
486
-------
SECTION 19
CARBON DIOXIDE INDUSTRY
19.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
19.1.1 Industry Profile and Analytical Results
Carbon dioxide is produced in gaseous, liquid or solid form.
A major portion of the production is used captively for the
production of urea and for the secondary recovery of oil and
natural gas. It is also used for refrigeration, in the food
industry, for the carbonation of beverages, in fire extinguishing
equipment, and oil well stimulation.
The industrial data profile for this subcategory is given in
Table 19-1, while existing regulations are summarized in Table
19-2.
The only priority pollutant found at a significant
concentration in the raw waste during screening at Plant #241
was:
Pollutant
Concentration (ug/1)
910
when the data was reviewed with plant personnel, it was
discovered that the high zinc level was due to zinc corrosion
inhibitors and were not process related. Therefore, this
subcategory has been recommended as an exclusion candidate under
Paragraph 8.
487
-------
TABLE 19-1. -
SUBCATEGORY PROFILE DATA SUMMARY
SUECATEGORY
CARBON DIOXIDE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
12,194,000 kkg/year
1,819,000 kkg/year
105
12
713,947 kkg/year
558,667 kkg/year
59 percent
31 percent
1,600 kkg/year
155,000 kkg/year
6 years
50 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
488
-------
19-2 - EXISTING REGULATIONS - EFFLUENT KCMTTATICN GUIDELINES
t^==. :
SUBCATEGORY Carbon Dioxide
SUBPART
— -
Product
Process
AF (40CFR 415.320,
BPCTCA
Max.1 Avg.2
Para- kg/kkg k/kkg
meters (mg/1) (mg/1)
5/22/75)
STANDARDS
BATEA
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
NSPS
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
CO Reserved Reserved Reserved Reserved
£
wax, = Maximum of any one day.
Avg. = Average of daily values for thirty consecutive days shall not exceed.
489
-------
SECTION 20
CARBON MONOXIDE AND BY-PRODUCT HYDROGEN INDUSTRY
20.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
20.1.1 Industry Profile and Analytical Results
In the production
carbon monoxide is also
from several gas sources
natural gas, coke oven
methane reformer gas.
of hydrogen by refining natural gas,
produced. Carbon monoxide is recovered
including partial combustion of oil or
gas, blast furnace gas, water gas, and
Carbon monoxide and by-product hydrogen form the building
blocks for other chemicals such as ammonia and methanol. The
major use of carbon monoxide is for the manufacture of methanol.
It is also used as a
special steels, ' and nickel
the manufacture of ammonia,
gaseous fuel for reducing oxides for
refining. Carbon monoxide is used in
acetic acid, and zinc white pigments.
The industrial profile data for this subcategory is given in
Table 20-1, while existing regulations are summarized in Table
20-2.
Priority pollutants found at significant
waste during screening at Plant #981 were:
levels in the raw
Pollutant
Chromium
Zinc
Silver
Mercury
Concentration (ug/1)
2590
820
1.4
1.2
The only pollutants of significance in terms of waste loads,
in the carbon monoxide subcategory are chrome and zinc. However,
this is the result of the use additives in cooling water to
inhibit corrosion, and is not process related. Therefore this
subcategory has been recommended as a Paragraph 8 exclusion
candidate.
490
-------
TABLE 20-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
CARBON MONOXIDE AND BY-PRODUCT HYDROGEN
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
277,200 kkg/year
5
5
112,400 kkg/year
40 percent
47 kkg/year
63,000 kkg/year
8 years
19 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Coimerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
491
-------
20-2 - EXISTING REGULATIONS - EFFLUENT .LIMITATION GUIDELINES
Carbon Monoxide and By-Product Hydrogen
SUBPAKT AG (40CFR 415.330, 5/22/75)
~ STANDARDS
BPCTCA BATEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/D (mg/1) (mg/1) (mg/1)
^ 0 5 0 25
and rnn u.^o
2 LUU (81.3)* (40.7)
2 TSS °'12 °'06
ibb (19.5) (9.8)
"wax, = Maximum of any one day.
Avg. = Average of daily values for thirty consecutive days shall not exceed.
*flow basis 6150 1/kkg.
492
-------
SECTION 21
COPPER SULFATE INDUSTRY
21.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
21.1.1 Industry Profile and Analytical Results
Most of the copper sulfate produced is sold in the merchant
market, consequently captive use is very small. Copper sulfate
is used in agriculture as an insecticide and algicide, and as an
addition to copper-deficient soils. It is also used in
electroplating and in petroleum refining, and as a preservative
for wood.
The industrial profile data for this subcategory is given in
Table 21-1, while existing regulations are summarized in Table
21-2.
Priority pollutants found at significant concentrations in
the raw waste during screening at Plant #034 were as follows:
Pollutant Concentration (ug/1)
Antimony 307
Arsenic 3500
Cadmium 870
Copper 1,850,000
Lead 175
Nickel 112000
Zinc 11000
1,1,1-trichloroethane 244
A large portion of the raw waste water at this plant
consists of ground water which seeps and collects in the
basement, along with leaks and washdown water from the process.
The ground water is contaminated from the surrounding area which
is heavily industrialized. The trichloroethane is presumed to be
external contamination.
A summary of daily and unit product raw waste loads for the
Plant sampled" can be found in Table 21-3. No verification
493
-------
TABLE 21-1
SUBCmEGORY PROFILE DATA SUMMARY
SUBCATEGORY
COPPER SULFATE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
37,000 kkg/year
18
10
32,218 kkg/year
28,960 kkg/year
78 percent
45 kkg/year
9,100 kkg/year
2,020 kkg/year
510 kkg/year
50 percent
3 years
52 years
0 cubic meters/day
28 cubic meters/day
<0.1 cubic meter/kkg
2.1 cubic ireter/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Carroerce, Current Industrial
Inorganic Chemical Industry."
494
-------
21-2 -
EXISTING REFLATIONS - EFFLUENT UMTTATICN GUIDELINES
SOBCMEGOKf
SUBPAKT
Copper Sulfate
AT (40CFR 415.360, 5/22/75)
• STANDARDS
BPCTCA
Product
Process
Pure Raw
Materials
Process
Recovery
Process
Para-
meters
Cu
Cu
Ni
Se
Max.
kg/kkg
(mg/D
0.0006
0.069
(74.2)*
0.003
(3.2)
0.006
(6.5)
0.0015
(1.6)
Avg.
k/kkg
Cmg/1)
0.0002
0.023
(24.7)
0.001
(1.1)
0.002
(2.2)
0.0005
(0.5)
BATEA NSPS
Max. Avg. Max. Avg.
k/kkg k/kkg k/kkg k/kkg
(mg/1) (mg/1) (mg/1) (mg/1)
= Maximum of any one day.
*Avg. = Average of daily values for thirty consecutive days shall not exceed.
*flow basis 930 1/kkg.
495
-------
TABLE 21-3. SUMMARY OF RAW WASTE LOADINGS FOUND AT COPPER SULFATE PLANT
•
Pollutant
Priority
Antimony, Sb
Arsenic, As
Cadmium, Cd
Copper, Cu
Lead, Pb
Nickel, Ni
Zinc, Zn
Conventional
TSS
kg/day
Average
0.014
0.16
0.039
83.9
0.0079
5.08
0.50
1.78
Loadings
kg/kkg
Average
0.00069
0.0078
0.0019
4.11
0.00039
0.25
0.024
0.087
496
-------
sampling was performed in this subcategory because no additional
plants with single product waste streams could be identified.
Based on the total annual production rate of this
subcategory and the average waste load generated per unit
product, the estimated total pollutant raw waste loads generated
each year for this subcategory are as follows:
Pollutant Waste Load (Kg/year)
Antimony
Arsenic
Cadmium
Copper
Lead
Nickel
Zinc
25.5
287
70
152,070
14.5
9,250
888
21.1.2 Process Waste Sources and Waste Water Treatment Data
General Process Description
Raw material and_ process - Copper sulfate is produced by
reacting coppef~sho~t7~( blTster copper) with sulfuric acid, air,
and water. The general reaction is:
Cu + 1/2 02 + H2S04 = CuS04 + H20 (1)
Some plants do not start with copper metal but use a waste
stream from copper refineries which consists of copper, sulfuric
acid, and a small amount of nickel. The solution needs to be
strengthened by the addition of more copper but the same general
equation applies.
The resulting copper sulfate solution is either sold or fed
to crystallizers producing copper sulfate crystals. These are
centrifuged, dried, screened, and then packaged dry for sale.
Water Use and Waste Source Inventories
Water uses - Water is used in the process as a reaction
component which becomes a part of the dry oro.duct as its water of
crystallization. Water is also used for noncontact cooling, pump
seals, and washdowns. Table 21-4 gives a summary of plant water
usages.
497
-------
TABLE 21-4 WATER USAGE IN COPPER SULFATE SUBGATEGORY
Plant
#284
#313
# 069
# 571
# 885
# 458
# 100
# 969
# 050
Process Contact
m Akg
1.210
24.76
4.35
0.150
2.11
3.59
1.28
1.28
1.28
Noncontact
Cooling
m /kkg
0
37.29
138.4
0
0
0
0
0
0
Pump, seals,
leaks, etc..
0.346
0.278
4.96
0.033
Nil
Nil
Nil
Nil
Nil
washdown
.m /kkg
498
-------
Waste_ Sources
A. Noncontact cooling water is used in the crystallizers
and constitutes one of the main wastes. This waste is
treated before final discharge.
B. Washdowns, spills, and leaks are sources of contact
waste water, but the flows are relatively small and
intermittant, and do not represent a raajor waste source.
C. A few plants use evaporators, and steam condensate
is an additional noncontact waste formed in the process.
D. Solid waste is produced by some plants. The
copper metal used in the process contains copper sulfides,
which are filtered out of the liquor and disposed of
in a landfill.
Plants that produce copper sulfate in the liquid form have
no contact waste streams from the process. The copper metal,
acid, and water are reacted together to form the copper sulfate
solution product with no generation of liquid wastes.
Control and Treatment Practices
Treatment practices - Plant #034 uses lime neutralization
followed by filtration. The filtrate is discharged to a sewer
and the filter cake is hauled to a landfill.
Plant #284 practices lime neutralization with aeration and
clarification.
Plant #069 has neutralization and equalization treatment
before the waste is discharged to a sewer.
Plant #313 uses lime precipitation at pH 10 followed by
gravity separation and centrifugation to thicken the sludge. The
waste is then neutralized to pH 6.5-7.5 and discharged. Plants
HOO, #969, #050, #458, #885 and #571 have no treatment.
Description of Plants Visited and Sampled
Plant #034 was the only plant visited and sampled. This was
done during screening and no verification sampling was conducted
for this subcategory.
The waste from the plant drains into a sump from which it is
pumped to two neutralization tanks where lime is added. The
waste is then run through a filter press and the filter residue
is hauled to a landfill disposal site. The filtrate is mixed
499
-------
with noncontact cooling water and steam condensate in a
collection tank. The wastes are then passed through a cloth
filter for final polishing and discharged to a sewer. Figure
21-1 shows the process flow and sampling points for this plant.
Table 21-5 gives the waste flows and classical pollutant
emissions.
Evaluation of Production and Waste Water Flow Data
Table 21-5 shows that the treatment efficiency for copper
removal is above 99.5 percent at Plant #034. All other copper
sulfate plants treat their wastes with other process wastes or
they have no wastes. This plant was the only plant visited for
those reasons.
Process Modifications and Technology Transfer Options
Mechanical scrapers should be installed on filters in plants
using impure raw materials. This would eliminate the need for
backwashing so no waste water would be produced. Solids wastes
would still have to be disposed. Installation of these scrapers
would constitute a small capital cost.
Best Management Practices
The best technology available for the treatment of copper
sulfate waste, where pure copper is used as the raw material, is
total recycle of process waste. This would require floor dikes,
plumbing and sumps, and mother liquor recycle pumping and piping.
The best technology for waste treatment where copper sulfate
is prepared from copper refinery by-product is collection of
waste mother liquor and process spills, washdowns, etc., followed
by lime precipitation of metal ions with settling of suspended
solids and filtration. This would require installing dykes,
sewers, a treatment tank, a settling tank, filter presses, and
associated piping and pumping (2).
Model Plant and BPT Level Treatment System Specifications
Production - Copper sulfate production ranges from 18900
kkg/yr to 189000 kkg/yr in plants for which 308 Questionnaires
were available. The average of the ten plants is 73710 kkg/yr.
The operational mode for all these plants is assumed to be batch
and to run 250 days per year.
Waste water flow - The waste water flow used for the model
plant was 0.9 m3/kkg of copper sulfate. Plant #748 has a waste
500
-------
FBQM
CU REFINERY
WASH WATER
STEAM
COOLING WATER
EVAPORATOR
Ul
O
H
SETTLED FILTER^
CAKE
Sample points.
CRYSTALLIZER
MOTHER
LIQUOR
CENTRIFUGE
MOTHER LIQUOR
TO OTHER PROCESS
DRiER
CUSO.
STEAM CONDENSATE
NONCONTftCT
COOLING
WATER
SPUXS, LEAKS,
SEEPAGE, CLERNUP
111 LIME
NEUTRALIZER
TANKS
(2)
I
FILTER
PRESS
COLLECTION
TANK
COOLING
WATER
Figure 21-1. General process flow diagram at Plant #034 showing
the sampling points. Copper Sulfate Manufacture
-------
TABLE 21-5. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT #034 PRODUCING COPPER SULFATE
- .
Waste Stream
Description
CuSO. waste*
Effluent from
Flow
m /kkg
2.23
2.23
TSS
kg/kkg
0.0862
0.0769
Phenol
kg/kkg
0.00004
0.000027
Cu
kg/kkg
4.11
0.0101
Ni
kg/kkg
0.248
_
lime treatment
Steam Condensate
0.371 0.00133
0.00167
Infiltration of ground water into the collection sump was suspected at the
time of sampling.
502
-------
flow of
combine
CuS04 to
0.52 m3/kkg of copper sulfate. All the other plants
their wastes with other process wastes or purify the
reagent grade which produces more waste.
Solid wastes - Copper sulfide from filtration is the only
solid waste that requires disposal. This waste must be disposed
of in a chemical landfill since the solids may contain other
contaminants or become oxidized and commence to migrate into the
soil or ground water.
Slimes from the mother liquor and copper sulfate solid
wastes are all recycled or sent to another facility for precious
metal recovery.
Treatment chemicals
precipitate metals and for
Caustic soda is required to
pH adjustment, usually at pH to 9-10.
For model plants, the assumed caustic soda dosage was 0.33
Kg/kKg of copper sulfate, calculated as 350 mg/1 in a unit waste
flow of .52 m3/kkg of product.
Solids generated - Based on sludge production of 5 Ibs/day
for 250 days/yr in the model plant, the annual solids production
is 340 kg, equivalent to unit solids generation of 0.0046 kg/kkg
of product.
21.2 TECHNOLOGY BASED POLLUTION ABATEMENT
21.2.1 Advanced Level Treatment Applications
Priority Pollutants to be Controlled
The priority pollutants found in actual plant waste waters
are closely related to the purity of the copper and acid sources.
The heavy metals, cadmium, nickel and zinc, which were found
during field sampling, may originate as trace impurities in
copper scrap. Arsenic was found at one plant in waste water
containing floor washings and infiltrated groundwater. A
possible source of arsenic, and other copper ore trace metals, is
the use of sulfuric acid made from sulfur dioxide produced in the
roasting of copper sulfide ore. In any event it appears that
copper, arsenic, cadmium, nickel and zinc are typical pollutants
encountered in copper sulfate waste waters. Assuming that the
material sources may at some time include impure acid, copper
scrap and spent electrolyte solutions, the priority pollutants to
be controlled are copper, zinc, nickel cadmium and arsenic.
503
-------
Removal Technologies Available
Copper, nickel,
solution by alkaline
to 9.7 (cadmium).
used. These metals
by ion exchange, but
cadmium and zinc can be separated from
precipitation at pH values from 7.2 (copper)
Alternatively, sulfide precipitation can be
can also be removed from clarified solutions
the metal ions remain on the exchange resins
or in the regenerant solutions possibly creating additional
disposal problems. Removal of trace metal concentrations by the
xanthate process, although possible, has not been widely used.
Some reduction of arsenic concentrations at high pH levels has
been reported, although the removal mechanism is not clear. More
effective arsenic removal would require the addition of ferric
chloride during alkaline or sulfide precipitation of the process
wastes.
Technology to be Applied at Each Level
BPT Model (Level 1) - Alkaline precipitation using caustic
soda in a batch process was chosen as the most effective
technology for removal of heavy metals and arsenic. To suit a
40-hour, five-day production schedule the wastes are received in
daily batches, and are raised to pH 10, mixed, and settled. At
the end of the work week, the batch is filtered and the pH
adjusted to between 6 and 9.
Level _2 - Ferrous sulfide is
following alkaline precipitation,
of trace metals.
added in the reaction vessel
to increase the precipitation
Flow Diagrams
Level 1
Figure 21-2
Level 2
Figure 21-3
Equipment Functions - At both levels the models are designed
for batch operation.Each day's wastes are transferred from
holding sumps to a reaction vessel for storage. At the end of a
work week the BPT treatment of the accumulated waste consists of
adding caustic soda to pH 10, mixing, and applying filter aid
while filtering in a filter press. After pH adjustment to the 6
to 9 range, the filter effluent is discharged. In the Level 2
model the equipment remains the same but precipitation is carried
out in two steps. Metallic hydroxides are allowed to form and
settle in the bottom of the reaction vessel. Then ferrous
sulfide is added to the reactor and mixed, to react with residual
metals. Following completion of sulfide precipitation, filter
504
-------
CAUSTIC
SODA
HOLDING
TANK
tn
O
Ul
RAW WASTE WATER
FILTER AID-
REACTION
TANK
pH ADJUSTMENT
FILTER PRESS
EFFLUENT
*
Includes flow monitoring, pH monitoring and sample
LANDFILL
Figure 21-2. Waste water treatment Level 1 for copper sulfate subcategory - batch process.
-------
SODIUM
BISULFIDE
FILTER AID—|
REACTION
pH ADJUSTMENT
'includes flow monitoring, pH monitoring and sampler
LANDFILL
Figure 21-3. Waste water treatment Level 2 for copper sulfate subctitegory - batch proces
-------
aid is added while the mixture is being filtered through a filter
oress. As in Level 1, the pH is adjusted and the filter
effluent is discharged until the weekly batch is exhausted.
Chemicals and Handling - Caustic soda solution is added
manually to each batch until the proper pH level is reached. In
Level 2, batches of ferrous sulfide are prepared by mixing
ferrous sulfate and sodium bisulfide in a well-ventilated area.
Inert filter aid is applied as a filter precoat and is added
continuously during the filtering process. With normal
precautions there are no special chemical handling problems in
the treatment of copper sulfate wastes.
Separation and Removal o_f_ Solids - All solids in both levels
are collected as filter cake in the filter press, taken out of
service and cleaned. At both levels the dewatered cake
containing metallic hydroxides, metallic sulfides, and spent
filter aid is hauled to an off-site chemical landfill.
Monitoring Regui rements - Alkaline precipitation of the
heavy metals is assured by bringing the reaction vessel contents
to the proper pH, as determined by the operator, using field pH
equipment. Periodic specific analyses of the final effluent for
priority pollutants for reporting purposes can be made by atomic
absorption methods through a commercial laboratory.
21.2.2 Estimated Performance o_f BPT Systems
Copper sulfate can be manufactured using pure copper as the
raw material or an impure copper raw material. Waste loads
emanating from the two sources differ greatly in that total
recycle of process wastes can be accomplished at plants using a
pure copper source, while at plants using an impure raw material,
waste streams need to be removed to some extent to avoid build-up
of contaminants in the process.
Based on the process technology of total recycle at plants
using a pure raw material, it has been determined that the degree
of waste control attainable is no discharge of process wastes.
BPT technology for copper sulfate plants utilizing an impure
raw material has been identified as hydroxide treatment to
precipitate metals followed by settling and filtration to remove
suspended solids. Table 21-6 presents raw wastes and treated
effluent quality results from sampling of Plant ff034 where
treatment consists of lirne precipitation and solids removal with
a filter press.
507
-------
TABLE 21-6. VERIFICATION SAMPLING OF COPPER SULFATE PLANT #034
Pollutant
Flow =2.23 m /kkg
Raw Waste
mg/1 kg/kkg
Treated Effluent
kg/kkg
Total Suspended
Solids (TSS)
Copper, Cu
Nickel, Ni
Antimony, Sb
Arsenic, As
Cadmium, Cd
Chromium, Cr
Lead, Pb
Selenium, Se
Zinc , Zn
39.2
1850
112
0.33
3.50
0.870
0.142
0.180
< 0.011
11.1
0.087
4.1
0.248
0.0007
0.0078
0.0019
0.00038
0.00039
0.000024
0.025
35.0
4.65
0.240
0.036
< 0.020
0.001
0.005
0.005
0.100
0.016
0.078
0.010
0.0005
0.000079
0.000044
0.000002
0.00001
0.00001
0.00022
0.000035
>\
Before combining with non-contact cooling and steam condensate streams.
Monitoring Data - Treated Effluent
Total Suspended Solids, TSS
Copper, Cu
Nickel, Ni
Zinc, Zn
Arsenic, As
Selenium, Se
Flow = 3.7 m /kkg
Avg.
26
4.3
0.34
0.12
0.012
0.007
mg/1
day Avg.
62.4
6.9
0.75
0.29
0.041
0.043
Avg.
kg/kkg
0.096
0.016
0.0013
0.00044
0.000044
0.00003
508
-------
Base Level Performance Characteristics for BPT Pollutant Removal
Based on effluent quality achieved at Plant #034,
implementation of BPT technology at copper sulfate plants using
an impure raw material will achieve the effluent quality
presented in Table 21-7.
Previous regulations included selenium limitations, however,
selenium was not found to be a significant pollutant in raw
wastes at Plant #034.
Base Level Performance Characteristics for Priority Pollutant
Removal
Raw waste priority pollutants found in significant amounts
during sampling of Plant #034 were presented above. The
additional pollutants which might require regulation were
identified as arsenic, cadmium and zinc.
Table 21-7 also presents achievable effluent quality through
implementation of BPT technology for these pollutants.
Pretreatment Applications
No copper sulfate plant presently discharges waste to a
POTW, however, Plant #034 does plan to discharge to a municipal
facility in the future. The toxicity of copper is a concern as
it can have a detrimental effect on POTW biota and also can
accumulate in municipal sludges. The volume of waste produced by
a copper sulfate plant is small enough so that total copper loads
discharged following effective BPT treatment can be accepted by
large POTW's. However, for general application, pretreatment
will require careful waste water volume control.
21.2.3 Estimated Performance of Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutants Removal
Only one advanced treatment alternative has been identified
for the Copper Sulfate Subcategory. Addition of sulfide before
filtration for further removal of copper and other heavy metals
is proposed.
Table 21-3 presents estimates achievable effluent quality
through implementation of this advanced technology.
509
-------
TABLE 21-7 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Copper Sulfate
Level of Treatment: 3
Waste Water Flow: 0.9 m3/kkg
D/-v Tin
BPT Eants
Totalande
Solid?
Coppe
Nicke
SelerSe
P r o per i o r
Pollu
Arsers
Cadmfl
Zinc ,
Subcategory
Do v f r\ irn 3 n ^ o
(mg/l)
m
d 62
6.9
0.7
0.04
ity
0.04
(2;
0.001
0.3
(1)
VFR
2.0
2.0
2.0
2.0
2.0
)
2.0
2.0
Quality Limit
(mg/l)
30 day 24 hr
Aver Max
15 30
2.5 5.0
0.5 1.0
0.1 0.2
0.1 0.2
0.05 0.1
0.4 0.8
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
0.014 0.027
0.0022 0.0045
0.00045 0.0009
0.0001 0.0002
0.00009 0.00018
0.00004 0.00009
0.00036 0.00072
(1]R: ratio of the 24 hour variability factor to the
30 day variability factor.
(2]rification Sampling
510
-------
TABLE 21-8 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Copper Sulfate
Level of Treatment: 2
Waste Water Flow: 0.9 m3/kkg
DA! 1 ni'ant1 Trp;
BPT Pollutants:
Total Suspended
Solids, TSS
Copper, Cu,
Nickel, Ni
Selenium, Se
Proposed Priority
Pollutants
Arsenic, As
Cadmium, Cd
Zinc, Zn
^ 1* ah i 1 i h v
(mg/1)
15
0.5
0.2
0. 1
0.05
0.01
0. 2
(1)
VFR
2.0
2.0
2.0
2.0
2.0
2.0
2.0
Quality Limit
(mg/1)
30 day 24 hr
Aver Max
15 30
1.0 2.0
0.2 0.4
0.1 0.2
0.05 0.1
0.01 0.02
0.2 0.4
Emission Limit
(kg/kkg)
30 day 24 hr
Av e r Max
0.014 0.027
0.0009 0.0018
0.0002 0.0004
0.0001 0.0002
0.00004 0.00009
0.00001 0.00002
0.0002 0.0004
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
511
-------
Pretreatrnent Applications
Only one copper sulfate plant is planning to discharge waste
to a POTW following pretreatment. Should further metals removal
be required due to the sensitivity of a particular POTW, the
application of this advanced technology would then be
appropr iate.
New Source Application
After examination of the effectiveness of the two treatment
technologies applicable to copper sulfate wastes, it has been
determined that BPT technology in conjunction with careful waste
water volume control in the design and operation of a new copper
sulfate facility should achieve effluent quality equivalent to
that quality estimated for the advanced technology.
21.2.4 Cost Estimates
Discussion
The cost estimate of one model plant having two levels of
treatment and the same level of production at both the levels is
presented in Table 21-9. Table 21-10 gives a summary of the unit
cost distribution between amortization and operation and
maintenance cost components at two levels of treatment.
Summary
Cost estimates developed for the first level of treatment
indicate that amortization and labor constitute a major portion
of the annual costs. At the second level of treatment there is
insignificant change in the annual costs.
512
-------
TABLE 21-9. MODEL PLANT TREATMENT COSTS
Subcategory COPPER SULFATE
Production 2,045 metric tons per year (
5 metric tons per day (
Waste water flow 8 cubic meters per day.
Type of Regulation BAT
2,254 tons per year)
6 tons per day )
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, contingencies.,.
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Ma intenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
LEVEL OF TREATMENT*
FIRST SECOND
$9,200
53,000
9,000
14,240
14,240
1,200
$100,880
$8,000
15
1,000
9,968
3,026
100
2,500
$24,609
$16,217
$40,826
$200
1,000
240
240
$1,680
30
168
50
1,250
$1,498
$273
$1,771
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
513
-------
TABLE 21-10 MODEL PLANT TREATMENT COSTS
Subcategory COPPER SULFATE Type of Regulation BAT
Annual Treatment Costs ($/kkg)
LEVEL OF TREATMENT
PRODUCTION FLOW FIRST SECOND THIRD FOURTH
(kkg/yr) (m3/day) $ $ $ $
Annual Operation
and Maintenance 2,045 8 12.03 0.73 Not Applicable
Annual
Amortization 2,045 8 7.93 0.13
Total Cost 2,045 8 19.96 0.87
514
-------
SECTION 22
NICKEL SULFATE INDUSTRY
22.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
22.1.1 Industry Profile and Analytical Dat a
Most of the nickel sulfate produced is sold in the merchant
market. The major use of nickel sulfate is in the metal plating
industry. It is also used in dyeing and printing fabrics and for
producing a patina on zinc and brass.
The industry profile data summary is given in Table 22-1,
while existing regulations are summarized in Table 22-2.
Priority pollutants found at significant concentrations in
the raw waste during sampling at Plant #369 were as follows:
Maximum Concentration Observed
Pollutant (ug/1)
Screening Verification (2 Plants)
Nickel
Copper
Chromium
Thallium
Lead
Mercury
Cadmium
Selenium
175,500
73,300
1,300
21
55
4
9
<235
1,115,000
355
110
<3
120
10
160
141
A summary of daily and unit product raw waste loads for all
plants sampled can be found in Table 22-3. Individual plant raw
waste loads per unit product found in sampling can be found in
Table 22-4.
The total annual production rate for
unavailable at this time. Therefore,
pollutant waste loads generated by this
calculated and presented.
this subcategory is
the total priority
industry cannot be
515
-------
TABLE Z2-1
SUBCATEGORy .PROFILE DATA .SUMMARY
SUECATEGORY
NICKEL SULFATE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
12
6
24,770 kkg/year
17,670 kkg/year
62 kkg/year
8,250 kkg/year
2,100 kkg/year
1,600 kkg/year
3
48
< 1 cubic maters/day
200 cubic meters/day
< 1 cubic meters/kkg
20 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
516
-------
TABLE 22-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SUBCATEGORY Nickel Sulfate
SUBPAKT
AU (40CFR 415.470,
5/22/75)
STANDARDS
Product
Process
Pure
Raw
Materials
Impure
Raw
Materials
BPCTCA
Max. Avg,
Para- kg/kkg k/kkg
meters (mg/1) (mg/1)
„. No discharge
of pwwp 3
TSS No discharge
of pwwp
N. 0.006 0.002
(5.1)* (1.7)
0.096 0.032
(82.1) (27.4)
BATEA
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
No discharge
of pwwp
No discharge
of pwwp
NSPS
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
No discharge
of pwwp
No discharge
of pwwp
wax, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants,
* flow basis 170 1/kkg.
517
-------
TABLE 22-3. SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
CO
SUBCATEGORY NICKEL SULFATE
Pollutant
Minimum
Priority
Cadmium, Cd 0.000014
Chromium, Cr 0.00023
Copper, Cu O'.OOll
Lead, Pb 0.000082
Mercury, Hg
Nickel, Ni 0.27
Selenium, Se 0.00027
Thallium, Tl
Conventional
TSS 0.34
Loadings
kg/day
Average Maximum Minimum
0.0015 0.0045 0.000002
0.00091 0.0018 0.00001
0.039 0.11 0.0001
0.0014 0.0028 0.00002
0.000027
10.8 31.5 0.035
0.00059 0.00091 0.00003
0.000032
31.2 92.5 0.031
kg/kkg
Average Maximum
0.00017 0.0005
0.00025 0.0005
0.01 0.03
0.0001 0.0003
0.00003'
1.20 3.45
0.000035 0.00004
0.000009
10.1
No. of Plants
Averaged
3
2
3
3
1
3
2
1
-------
22-4. PRIORITY POLLUTANT RAW WASTE LOADS (in kg/kkg of Product)
SUBCATB30RY
POLLUTANT
Nickel, Ni
Copper,. Cu
Chronium, Cr
Lead, Pb
Zinc, Zn
Mercury, Hg
Cadmium, Cd
Selenium, Se
Thallium, Tl
NICKEL
SULFATE
PLANT
#369
0.073
0.030
0.0005
0.00002
0.00011
0.000004
0.000009
#572
3.45
0.0001
0.0003
0.0012
0.0003
0.0005
0.00003
#120
0.035
0.0002
0.00001
0.00006
0.00004
0.000002
0.00004
519
-------
22.1.2 Process Waste Sources and Waste Water Treatment Data
General Process Description
Raw materials and process - Two different
used to producenickel sulfate. Pure nickel
powder is used or spent nickel catalysts,
solutions or residues. The general reaction is:
raw materials are
or nickel oxide
nickel plating
NiO + H2S04 =
NiS04
H20
(1)
The nickel sulfate produced when pure raw materials are used
is filtered and sold or processed further using a crystallizer to
produce a solid nickel sulfate product. This must be classified,
dried, and screened before it is ready for sale.
The use of impure raw materials produces a nickel sulfate
solution which must be treated in sequence with oxidizers, lime
and sulfides to precipitate impurities which are then removed by
filtration. Tiie nickel sulfate solution can be sold or the
product may be crystallized, classified, dried, and screened to
produce solid nickel sulfate for sale.
Water Use and Waste Source Inventories
Water uses - Noncontact cooling water is used for nickel
sulfate production in the reactor and in crystallizers. Water is
used for direct process contact in the reactor. Small amounts of
water are used for maintenance purposes, washdowns, cleanup, etc.
Table 22-5 gives a summary of water usage.
Waste Sources
Noncontact cooling water is the main source of waste water,
but it is not usually treated before discharge.
Direct process contact water constitutes the major portion
of treated waste. The waste comes from the preliminary
preparation of spent plating solutions used in the process.
Plants which use impure nickel raw materials generate a filter
backwash waste stream with high impurity levels. This stream
must be sent through the treatment system.
Washdowns, spills, pump leaks, and maintenance
for the remaining wastes produced by nickel sulfate
uses account
plants.
520
-------
22-5. WATER USAGE IN THE NICKEL SULFATE SUBCATEGORY
|120
*
Includes uses for other processes.
plant Non-contact cooling Direct Process contact Micellaneous
m3/kkg m3/kkg (^'_ J
m /kkg
#313 * 37.29 24.76 0.278
#069 1.67 0.0098 0.0196
#572 * 4.98 0.349 0.896
0.417 0.783 0.094
13.64 4.013 Nil
*
#603 2035 814 Nil
521
-------
Control and Treatment Practices
Treatment practices at Plants #313, #069, #572, #369 and
#120 all employ caustic precipitation of metal-bearing waste
waters followed by filtration. The solid wastes are disposed of
or used as landfill at Plant #120, while the liquid wastes are
recycled to the process.
Plant #369 was visited in the screening phase of the
program. Treatment at this plant consists of adjusting the ptl to
between 9 and 10 for the precipitation of metal hydroxides which
are removed by settling prior to final discharge. Figure 22-1
shows the treatment system and sampling points. Table 22-6 gives
flows and pollutant emissions for the streams sampled.
Plants #572 and #120 were visited and sampled during the
verification phase of the program. At Plant #572, the wastes,
washdowns, leaks, and air scrubber water are put through an
equalization tank and then discharged to the municipal treatment
system. In the equalization tank, alkaline wastes from another
process are mixed in and the pH is raised to 10. Treatment of
process wastes at Plant #120 consists of pH adjustment to
precipitate nickel and other trace metals followed by sand
filtration. The wastes are mixed with other plant wastes and
discharged through a single outfall. Figures 22-2, 22-3, and
22-4 show the general flow sheets and waste streams sampled for
#572 and #120 respectively. Table 22-6 shows the waste streams
and loadings for both plants.
Evaluation of Production and Waste Flow Data
The flow for nickel sulfate wastes ranged from 0.417 m3/kkg
to 0.722 m3/kkg. This gives an average of 0.570 u3/kkg of
product. This data is based on the only two plants where the
NiS04 waste streams were separated from other wastes. All the
plants visited produced solid wastes as sludges but no flow data
was available.
Table
visited.
22-6 summarizes the waste flow data for all plants
Process Modifications and Technology Transfer Options
Mechanical scrapers should be installed on filters at plants
which use impure raw materials. This would eliminate the
backwash and reduce the amount of waste water produced. Solids
would need to be disposed. Installation of the scrapers would
amount to a very small capital cost.
522
-------
PROCESS
WASTES
NaOH
i
i
WASTE WATER
COLLECTION
SUMP
1^1
4^11
TREATMENT
TANK
to
•€^#3 ^
SLUDGE TO LANDFILL
DECANT
BATCH OPERATION
01
K>
U)
Sampling points.
TREATED EFFLUENT
TO SEWER
Figure 22-1. General waste water treatment process flow diagram showing
the sampling points. (Nickel Sulfate Manufacture)
-------
TABLE 22-6. FLOW AMD POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANTS PRODUCING NICKEL SULFATE
Stream
Flow
m /kkg
TSS Ni Cu Pb
kg/kkg kg/kkg kg/kkg kg/kkg
Untreated waste 0.417
Treated waste 0.417
Plant #369
0.073 0.031 0.0005
0.00058 0.0075 0.0002
Scrubber waste
3.15
Plant #572
10.15 3.45
0.00013 0.0003
NiSO. waste 0.722
All Nickel wastes 7.54
Treated effluent 7.54
Plant #120
0.031 0.0355
0.521 0.094
0.032 0.0015
0.00015 0.00004
0.0002
524
-------
Ul
K>
Ln
LEAKS, SPILLS, ETC., FROM
OTHER PROCESSES
NiSO.
SOLID WASTE
TO DISPOSAL
ALKALINE WASTES
Figure 22-2. General process flow diagram at plant #572 shewing the sampling points.
Nickel Sulfate Manufacture
-------
NICKEL
OXIDE
P»
DIGESTOR
i A «-»-.ir-ir-m
t
PLATING
• SODA ASH
EFFLUENT
CALCITE
-H
COOLINO
WATER
HOLDING TANK
DRYER
DUSTS
I
COOL, SCREEN,
PACKAGE
f
SCRUBBER
DUSTS
QC LAB
1IC ACID
ER
•£
SE
3OE
kM
JEVAPORAT10N TANK ^
STEAM
WATER
SOLID PRODUCT
Figure 22-3. -General process flow diagram of Plant #120.
Nickel Sulfate Manufacture
526
-------
OTHER NICKEL WASTES
NiSO. PROCESS
VfflSTE
SOLIDS TO NiSO.
PROCESS
Sampling points
DISCHAHGE
#3
Figure.22-4. General waste water treatment process flow diagram at Plant £120
showing the sanpling points.
(Nickel Sulfate Manufacture)
527
-------
Best Management: Practices
The best technology for the treatment of wastes when
starting with pure raw materials is to recycle all process
waters. To implement this treatment proper recycle piping and
pumping would be needed.
The best technology available where nickel sulfate is
manufactured from impure plating solution is caustic addition to
precipitate nickel followed by sand filtration to remove
suspended solids. This would require installing caustic
treatment tanks, filters, pH control equipment, and the necessary
piping and pumping.
Model Plant and BPT Treatment System Specifications
Best Practical Technology for plants using pure nickel as a
raw material is total recycle of all process water. A plant
using impure raw materials requires caustic neutralization of the
waste followed by sand filtration.
Waste system water flow - The flow used for the model plant
is 0.64 m3/kkg of nickel sulfate. This is based on the largest
producer in the industry. Plant #369 showed a waste flow of
0.416 m3/kkg and #120 showed 0.722 m3/kkg. Other plants have
combined waste waters and their flows are not known with
accuracy.
Production - Nickel sulfate production ranges from 96 kkg/yr
to 5,910kkg/yr in the plants for which 308 Questionnaires were
available. The average production for these six plants was 2,120
kkg/yr. The production levels selected for the model plant
ranged from 900 kkg/yr to 7,000 kkg/yr. The mode of operation at
all nickel sulfate plants is the batch process and, for the model
plant, is assumed to operate for 250 days/year.
Sol id waste generation - Solid wastes are generated from the
filtration "and settling of metals from the nickel sulfate
solution. The solids can be recycled to the process for reuse
when pure raw material is used. If the solids cannot be recycled
they must be disposed of in a chemical landfill because the
solids may contain contaminants that can pollute the soil or
ground water. The quantity generated is assumed to be 0.39 kg/kkg
of nickel sulfate.
Treatment chemicals - Caustic is required for neutralization
to precipitate the metals as their hydroxides. Acid is needed for
pH adjustment before final discharge. For the model plant, these
practices were assumed to use 0.0016 kg/kkg and 0.0001 kg/kkg
528
-------
respectively.
22.2 TECHNOLOGY BASED POLLUTION ABATEMENT
22.2.1 Advanced Treatment Applications
Priority Pollutants to be Controlled
The priority pollutants present in a specific process
operation depends upon the sources and nature of the raw
materials being used, which presumably could vary from time to
time. If impure raw materials include spent plating solutions,
most of the heavy metals (except nickel) will be rejected from
the process as sludges from the purification of the plating
solutions prior to nickel sulfate production. If these sludges
are handled as solids, they can be segregated for further
reclamation or for safe disposal at a chemical landfill. If
sludges from the process are discharged as slurries to the waste
treatment facilities they will be settled or filtered during the
treatment proposed for the model systems. The only significant
priority pollutant found in the sampling program was nickel.
Removal Technologies Available
Alkaline precipitation will remove nickel and most other
heavy metals from solution, allowing them to be settled and
filtered in successive steps. Nickel and the common heavy
raetals, except chromium can also be precipitated as metallic
sulfides, for later separation by settling and filtration.
Technology to be Used at Each Level
BPT - Because it is widely used in the industry, alkaline
precipitation with caustic soda is chosen as the BPT (Level 1)
model. With dual media filtration it is operated as a batch
process to suit the production schedule.
Level 2 - Alkaline precipitation is supplemented by the
addition of~ferrous sulfide, to precipitate dissolved nickel more
effectively before the filtration step shov/n in Level 1.
529
-------
Flow Diagrams
Level 1 Figure 22-5
Level 2 Figure 22-6
Equipment Functions - Wastes are received in a one-day
holding tank or waste water collection sump which is drained each
day to a reaction vessel. At the end of a normal work week, the
contents of the reaction vessel are raised to about pH 10 with
caustic soda, thoroughly mixed, and allowed to settle. The
separated liquids and serni-solids are then filtered and the final
effluent is adjusted to a pH from 6 to 9 before discharge. In
the small and medium models it is assumed that both the liquid
and the semi-solids in the reaction tank are filtered through a
high-pressure filter press, and discharged after pH adjustment.
In the highest production model, which produces 13 m3 per day of
wastes, seni-solids are filtered through a filter press and a
separate dual media filter is provided for filtering the decanted
liquid. In Level 2 the metallic hydroxide sludge is drawn off to
a sludge holding tank and the clarified supernatant in the
reaction tank is 'treated with ferrous sulfide, precipitating
metallic sulfides. The batch is then filtered through a filter
press (for small or medium plants) or through a filter press (for
semi-solids) and a dual- media filter (for supernatant) in the
larger operations.
Chemicals and Handling - Caustic soda in solution form is
used for alkaline precipitation at both levels to form insoluble
metallic hydroxides without precipitating calcium sulfate, as
would occur with lime application. Caustic soda solution is
handled in conventional equipment, or is drawn in batches from
shipping containers when small volumes are needed. In Level 2,
ferrous sulfide is prepared from ferrous sulfate and sodium
bisulfide. When these materials are mixed in a well ventilated
space and applied to the alkaline supernatant in the reaction
tank there are no special problems.
Separation and Removal o_f Solids - In the small and medium
production models, at both levels, essentially all solids are
collected in a filter press, which is periodically cleaned. The
dewatered sludge is hauled to a chemical landfill. In the larger
model plant, backwash from cleaning the dual medium filter
returns to the influent holding tank, from which the suspended
solids pass via the reaction tank and from there to the sludge
filter press.
Monitoring Requi rements - Satisfactory separation of heavy
metals can be assured by maintaining the proper reaction pH,
which can be determined manually on each batch, using simple
530
-------
BACKWASH
CAUSTIC
3ODA
Ln
00
RAW WASTE WATER f
pH ADJUSTMENT
Includes flow monitoring, pH monitoring and sampler
FILTER PRESS
LAND? ILL
•O-
EFFLUENT
Figure 22-5. Waste water treatment level 1 for nickel aulfate subcatejory - batch process.
-------
("FERROUS SODIUM
BA.CKWASH
M
CAUSTIC COD \ ' •-
j
I
1
t
HOLDING
TANK
»• 1
RAW WASTE 1 1 ' 1
WATER f L
I
3
^ OT^ A
J^ T
L-
POLYMER
TANK
pH ADJUSTMENT
ER
DUAL
MEDIA
FILTER
M
!____ g,
0^
FILTER AID
1
1
1
1
1
I
~XT
3><->->
SLUDGE
HOLDING TAKK
"j FILTER PRESS
Lr~ ~|
1
J
LANDFILL
EFFLUENT
Includes flow monitoring, pH monitoring and sampler
Figure 22-6. waste water treatment Level 2 for nickel sulfate subcategory - batch process.
-------
field equipment. Occasional monitoring of nickel in the effluent
for reporting purposes should be done by atomic absorption
methods on a sample of the liquid discharge. Monitoring for
dissolved sulfide should not be necessary, because unreacted
ferrous sulfide will oxidize to ferric sulfide and settle with
the other metallic sulfides.
22.2.2 Estimated Performance of BPT Systems
BPT technology has been specified as hydroxide precipitation
of metals, followed by filtration to remove suspended solids.
Plant #120 is currently practicing this technology. Table 22-7
presents effluent quality achieved at this facility as well as
results from the verification sampling program.
Base Level Performance Characteristics for BPT Pollutant Removal
Effluent quality achievable through implementation of BPT
technology is presented in Table 22-8 and is based on quality
achieved at Plant #120.
Base Level Performance Characteristics for Priority Pollutant
Removal
None of the additional priority pollutants identified were
found at levels that would require treatment.
Pretreatment Applications
Two nickel sulfate plants are known to presently discharge
to POTWs. Pretreatment at one plant is simple settling while at
the other, it is hydroxide precipitation followed by settling.
Considering the small waste water flows generated in the
manufacture of nickel sulfate, the application of BPT technology
is appropriate for pretreatment.
22.2.3 Estimated Performance o:f Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
Only one advanced treatment alternative has been developed
for the nickel sulfate subcategory. Addition of sulfide before
filtration for further removal of nickel is proposed.
533
-------
TABLE 22-1. WASTE CHARACTERISTICS OF NICKEL SULFATE PLANT #120
Verification Sampling: Flow = 0.72 m /kkg
Raw Waste Treated Effluent Quality*
Pollutant mg/1 kg/kkg mg/1
Avg. Max. Avg. Max. Avg. Max.
Total Suspen- 43 64 0.842 1.25 4.33 8
ded Solids
Nickel, Ni 49.15 75.80 0.962 1.48 0.2 0.34
Effluent Monitoring: Daily Data
Pollutant Concentration (rag/1) Waste Load (kg/kkg
Min Avg. Max St.Dev. Min Avq ^
Nickel, Ni 0.08 1.83 8.33 2.22 0.043 0.35 l.i-
534
-------
TABLE 22-8 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Nickel Sulfate
Level of Treatment: 1
Waste Water Flow: 0.64 m3/kkg
rOl 1 UT.au U
Subcategory
(mg/1)
(1)
VFR
Quality Limit
(mg/1)
30 day 24 hr
Av e r Max
Emission Limit
(kg/kkg)
30 day 24 hr
Av e r Max
BPT Pollutants :
Total Suspended 4.0(2) 2.0 15
Solids, TSS
Nickel, Ni
2.7
3.0
30 0.0096 0.019
2.0 6.0 0.0013 0.0038
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Verification sampling
535
-------
e 22-9 presents estimated achievable effluent quality
thmplernentation of this advanced technology.
Nee Applications
r examination of the effectiveness of the two treatment
teies applicable to nickel salfate wastes, it has been
ded that BPT technology in conjunction with careful waste
waume control in the design and operation of a new nickel
sifacility should achieve effluent quality equivalent to
y estimated for the advanced technology.
2< amortization and operation and maintenance cost
ccs at various production and levels of treatment.
: estimates developed for the first level of treatment
i that at a low production level labor cost has a
smt impact on the total annual costs. At medium
pm level, amortization, operation and maintenance costs
a important factors in the annual costs. At a high
p>n level, amortization cost is a significant factor in
til costs. At the second level of treatment, there is no
smt change in the annual cost, with production.
536
-------
TABLE 22-9 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Nickel Sulfate
Level of Treatment: 2
Waste Water Flow: 0.64 m3/kkg
Pollutant
Treatability
(mg/1)
(1)
VFR
Quality Limit
(mg/1)
Emission Limit
(kg/kkg)
30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants:
Total Suspended 15
Solids, TSS
Nickel, Ni
0.5
2.0 15
3.0
30 0.0096 0.019
0.5 1.5 0.00032 0.00096
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
537
-------
TABLE 22-10. MODEL PLANT TREATMENT COSTS
Subcategory NICKEL SULFATE Type of Regulation BAT
Production 900 metric tons per year ( 992 tons per year)
2 metric tons per day ( 2 tons per day )
Waste water flow 3 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $6,000 $100
Equipment in place,
including piping,
fittings, electrical
work and controls 29,500 900
Monitoring equipment
in place 9,000
Engineering design
and inspection 8,900 200
Incidentals, overhead,
fees, contingencies... 8,900 200
Land 1,800
TOTAL INVESTMENT COST $64,100 $1,400
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $8,000
Energy 30
Chemicals 200 30
Maintenance 6,230 140
Taxes and insurance... 1,923 42
Residual waste
disposal 100
Monitoring, analysis
and reporting 2,500 1,250
TOTAL OPERATION AND
MAINTENANCE COST $18,983 $1,462
C. AMORTIZATION OF
INVESTMENT COST $10,136 $227
TOTAL ANNUAL COST $29,119 $1,689
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
538
-------
TABLE 22-11.MODEL PLANT TREATMENT COSTS
Subcategory NICKEL SULFATE
Production
Type of Regulation BAT
4,000 metric tons per year ( 4,410 tons per year)
11 metric tons per day ( 12 tons per day )
Waste water flow 11 cubic meters per day.
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Incidentals, overhead,
fees, contingenc ies...
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
LEVEL OF TREATMENT*
FIRST SECOND
$8,350
51,000
9,000
13,670
13,670
1,800
$97,490
$100
900
200
200
$1,400
Labor and supervision.
Chemicals
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$8 , 000
40
900
9,569
2,924
100
2,500
$24,033
$15,568
$39,601
75
140
42
1,250
$1,507
$227
$1,734
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost,
539
-------
TABLE 22-12. MODEL PLANT TREATMENT COSTS
Subcategory NICKEL SULFATE Type of Regulation BAT
Production 7,000 metric tons per year ( 7,717 tons per year)
20 metric tons per day ( 22 tons per day )
Waste water flow 18 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $12,000 $200
Equipment in place,
including piping,
fittings, electrical
work and controls 94,500 1,000
Monitoring equipment
in place 9,000
Engineering design
and inspection 23,100 240
Incidentals, overhead,
fees, contingencies... 23,100 240
Land 3,000
TOTAL INVESTMENT COST $164,700 $1,680
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $8,000
Energy 50
Chemicals 1,600 135
Maintenance 16,170 168
Taxes and insurance... 4,941 50
Residual waste
disposal 200
Monitoring, analysis
and reporting 2,500 1,250
TOTAL OPERATION AND
MAINTENANCE COST $33,461 $1,603
C. AMORTIZATION OF
INVESTMENT COST $26,308 $273
TOTAL ANNUAL COST $59,769 $1,876
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
540
-------
80 h
§60[-
o
| LEVEL #1
IEVEL
#2!
30
ICH
20
I i
I I
10
I i
I
2345
PRODUCTION, METRIC TONS/YEAR X 1000
Figure 22-7. Relationship of annual treatment cost to production for
the Nickel Sulfate Subcategory
541
-------
40
30
to-
EH
I 20
T~tT
\T
w
K
\\i
\\
w
IV
JS
^x
JLBVEL J2
10
LCVSIj #1
12345
PRODUCTION, METRIC TONS/YEAR X 1000
Figure 22-8. Relationship of annual unit treatment cost to production
for the Nickel Sulfate Subcategory
542
-------
TABLE 22-13 MODEL PLANT TREATMENT COSTS
Subcategory NICKEL SULFATE
Type of Regulation BAT
Annual Treatment Costs ($/kkg)
LEVEL OF TREATMENT
PRODUCTION FLOW FIRST SECOND THIRD FOURTH
(kkg/yr) (m3/day) $ $ $ $
Annual Operation
and Maintenance
Annual
Amortization
Total Cost
900
4,000
7,000
900
4,000
7,000
900
4,000
7,000
3
11
18
3
11
18
3
11
18
21.09
6.01
4.78
11.26
3.
3.
89
76
32.35
9.90
8.54
1.62
0.38
0.23
0.25
0.06
0.04
1.88
0.43
0.27
Not Applicable
543
-------
SECTION 23
SILVER NITRATE INDUSTRY
23.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
23.1.1 Industry Profile and Analytical Results
Most of the silver nitrate produced is for captive use in
the photographic industry- It is also used in the manufacture of
silver salts, mirrors, for silver plating, coloring porcelain and
as a chemical reagent.
The industry profile data is given in Table 23-1, while
existing regulations are summarized in Table 23-2.
Priority pollutants found at significant levels during
sampling ab Plant #609 were:
Concentration (ug/1)
Pollutant Screening Verification
Silver 164 65
Cyanide 580 470
Silver was not found at a significant concentration during
verification sampling of the same plant. However, a significant
level of cyanide was found again. The source of cyanide was found
to be from a soaking solution which is used to remove silver
nitrate stains from workers' clothes. This solution is sent to
the silver recovery treatment system. When plant personnel
discontinued this practice cyanides disappeared from the
effluent.
Action on this subcategory has been deferred in accordance
with Paragraph 8 of the Settlement Agreement. A new subcategory
including all silver compounds v/illbe reviewed under Phase II BAT
review.
544
-------
TABLE 23-1
SUBCATEGORY iPRQFZLE .DATA .SUMMARY
SUBCATEGORY
SILVER NITRATE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Miniirtum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
35,000 kkg/year
7
2
6,507 kkg/year
3,256 kkg/year
9 percent
50 kkg/year.
3,206 kkg/year
20 years
64 years
<1 cubic meters/day
38 cubic meters/day
1 cubic meter/kkg
4 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
545
-------
23-2 -
SDBCATEGOKf
SUBPAKT
EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
Silver Nitrate
BA (40CFR 415.530, 5/22/75)
STANDARDS
Product
Process
Para-
meters
BPCTCA
Max.1
kg/kkg
(mg/1)
BATEA NSPS
2
Avg. Max. Avg. Max. Avg.
k/kkg k/kkg k/kkg k/kkg k/kkg
(mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
AgNCL
Ag
TSS
0.009
(6.0)*
0.069
(46.0)
0.003
(2.0)
0.023
(15.3)
wax, = Maximum of any one day.
o
Avg. = Average of daily values for thirty consecutive days shall not exceed.
*flow basis 1500 1/kkg.
546
-------
SECTION 24
SODIUM BISULFITE INDUSTRY
24.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
24.1.1 Industry Profile and Analytical Results
Sodium Bisulfite is manufactured both in liquid and powdered
form. Captive use. is very small. Sodium bisulfite is used in
the manufacture of photographic chemicals, organic chemicals,
textile and in food processing. It is also used in the tanning
industry and in the sulfite process for the manufacture of paper
products..
The industry profile data are given in Table 24-1, while
existing regulations are summarized in Table 24-2.
Priority pollutants found at significant levels in the raw
waste during sampling at Sodium Bisulfite Plants were as follows:
Maximum
Pollutant Concentration Observed (ug/1)
Screening Verification (2 Plants)
Copper
Zinc
Cadmium
Chromium
Antimony
Lead
Mercury
Nickel
Silver
375
2,430
6
17
30
8
3
250
2
926
3,600
41
3,360
650
1,050
16.
455
<30
7
A summary of daily and unit product raw waste loads for all
plants sampled can be found in Table 24-3. Individual plant
raw waste loads per unit product found in sampling can be found
in Table 24-4.
The total annual production rate for this subcategory is
547
-------
TABLE 24-1
SUBCATEGOEY PROFILE DATA SUMMARY
SUBCATEGOKY
SODIUM BISULFITE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum.
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
9
2
46,000 kkg/year
28,300 kkg/year
4,700 kkg/year
23,600 kkg/year
17,800 kkg/year
16,900 kkg/year
62 percent
4 years
19 years
3 cubic meters/day
100 cubic meters/day
<<1 cubic meter/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
548
-------
TBBLE 24-2 - EXISTING REGULATIONS - EFFLUENT L3METATICN GUIDELINES
Sodium Bisulfite
SUBPAKT BB (40CFR 415.540, 5/22/75)
STANDARDS
BPCTCA BAIEA NSPS
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (nig/1) (mg/D (mg/D (mg/1) (mg/1)
Reserved Reserved Reserved Reserved
Max, = Maximum of any one day.
Avg. = Average of daily values for thirty consecutive days shall not exceed.
549
-------
TABLE 24-3.
SUMMARY OF RAW WASTE LOADINGS FOUND IN SCREENING AND VERIFICATION SAMPLING
SUBCATEGORY
Pollutant
Priority
Antimony, Sb
Cadmium, Cd
<-n Chromium, Cr
01
0
Copper, Cu
Lead, Pb
Mercury, Hg
Nickel, Ni
Zinc, Zn
Conventional -
TSS
COD
SODIUM BISULFITE
Minimum
0.00045
0.00023
0.018
0.005
0.000091
0.000091
0.0032
0.016
3.20
54.4
kg/day
Average
0.0018
0.0003
0.54
0.011
0.0045
0.00021
0.0068
0.18
12.9
117
Maximum
0.0041
0.00041
1.05
0.015
0.0095
0.00045
0.0091
0.42
25.4
234
Loadings
Minimum
0.000007
0.000004
OT0003
0.00007
0.000007
0.000001
0.00005
0.0002
0.21
1.33
kg/kkg
Average
0.000052
0.00001
0.011
0.00046
0.000092
0.000006
0.00031
0.0053
0.27
2.94
Maximum
0.00008
0.000017
0.022
0.001
0.0002
0.00001
0.0007
0.0088
0.38
4.04
No. of Plants
Averaged
2
3
2
2
3
2
3
3
-------
24-4.- PRIORITY POLLOTANT RAW V&STE LOADS (in kg/kkg of Product)
SODIUM BISULFITE
SUBCATEGORY
POLLUTANT
PLANT
#282
# 987
#586
Copper, Cu
Zinc, Zn
Cadmium, Cd
Chromium, Cr
Lead, Pb
Mercury, Hg
Nickel, Ni
Antimony, Sb
0.001
0.007
0.000017
0.000007
0.000007
0.0007
0.00007
0.00007
0.0002
0.000004
0.0003
0.00007
0.000001
0.00005
0.000007
0.0002
0.0088
0.00001
0.022
0.0002
0.00001
0.00017
0100008
551
-------
unavailable at this time. Therefore,
pollutant waste loads generated by this
calculated and presented.
the total
industry
priority
cannot be
24.1.2 Process Waste Sources a_nd Waste Water Treatment Dajta
General Process Description
Raw material and process - Sodium bisulfite is produced by
reacting sodium carbonate (soda ash) with sulfur dioxide and
water. The reaction is:
Na2C03
2S02 + H20 = 2NaHS03 +C02 (1)
This reaction produces a slurry of sodium bisulfite crystals
which can be sold, but which is usually processed to form
anhydrous sodium metabisulfite. This requires thickening,
centrifuging, drying, and packaging operations.
Water Use and Waste Source Inventories
Water uses - Direct process contact water is used to slurry
the sodium carbonate for the reaction. Noncontact cooling water
is another water use at one plant. Water is also used for pump
seals, maintenance and washdowns. Table 24-5 gives a summary of
water usage at the plants for which 308 Questionnaires were
avaliable.
Waste Sources - Noncontact cooling water from the centrifuge
is a source of waste at one plant. However, direct process
contact water is the main source of waste water which must be
treated, together with miscellaneous wastes such as water used
for maintenance purposes, washdowns, and spill cleanup.
Control and Treatment Practices
The Best Practicable Control Technology has been identified
as neutralization with caustic soda followed by aeration and
filtration. Aeration removes the reduced sulfur compounds which
contribute to a high COD in the raw waste.
Plant
blows air
d ischarged
#987 adds 50 percent caustic to the oxidation tank and
through while mechanically agitating. The waste is
to a river following the 17-hour retention period.
Plant #282 uses caustic soda or sodium carbonate for pH
control followed by sodium hypochlorite addition to oxidize
552
-------
WATER USAGE IN THE SODIUM BISULFITE SUBCATEGORY
Direct Contact Process Noncontact Cooling Maintenance
3 ,., 3 , WasMowns, etc.
m /kkg m /kkg J
m /kkg
#Z 0.872 3.85 0.843
#5 NA NA NA
#9 1.15 0 0.397
NA Bailable
553
-------
sulfite and other reduced sulfur species. The waste is then
neutralized and discharged to a County sewer.
Plant #586 mixes the bisulfite waste with waste from an
amine plant, and ZriS04 production wastes, and truck wash waste.
Lime is added to the wastes which are then passed through an
aeration tank with eight-hour's retention time. The treated
waste goes through primary and secondary settling before final
di scharge.
Plant #282 was visited in the screening phase of the
program. The bisulfite waste is treated on a batch basis every
two or three days. Sodium hypochlorite is added to the waste to
oxidize the sulfite. The oxidized sulfite waste is mixed with
wastes from an organic chemical plant and neutralized. The
combined wastes are then discharged to a sewer. Table 24-6 shows
the flow data and pollutant emissions, while Figure 24-1 gives
the process flow diagram and shows the sampling points used in
screening .
In verification, two plants were visited, namely #586 and
#987. At Plant #586 the sodium bisulfite wastes are combined with
many other process wastes and they are treated together. Figure
24-2 shows the flowsheet and the points sampled. Table 24-7
gives the pollutant emissions and flow data for the waste
streams. The filter wash is the main process waste at Plant
#987. This waste is neutralized with caustic soda to pH 9 - 10
to convert the bisulfite waste to sulfite. The sulfite is then
oxidized with air to sulfate. The treated waste, including
solids, is discharged to a river. Table 24-8 shows the pollutant
emissions and flow data for the waste streams sampled. Figure
24-3 shows the process flow diagram and sampling points at Plant
#987.
Evaluation of Production and Waste Flow Data
Screening and verification sampling showed significant
levels of zinc in the waste streams. Plants #987 and #586
effectively treated the wastes to remove the zinc. Plant #282
did not remove the zinc from the waste stream. This plant was
the smallest producer of sodium bisulfite of the plants sampled.
The waste flows varied from 0.102 m3/kkg for'#987 to 9.68 m3/kkg
at #586.
Model Plant Selection
Waste water flow - The sources of waste water include wet
air scrubbers, Eilter backwash, floor washings, leaks, and
spills. The unit flow rates ranged from O.lm3/kkg to 0.3ra3/kkg of
product at the three plants for which 308 Questionnaires were
554
-------
24-6. FLOW AND POLLIJTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT #282 PRODUCING SODIUM BISULFITE
Waste Stream
Untreated waste
Treated waste
TABLE 24-7. FLOW
Flow TSS COD Zn Cu
m3/kkg kg/kkg kg/kkg kg/kkg kg/kkg
2.67
2.67
AND POLLUTANT
STREAMS FOR PLANT
0.237 4.04 0.0067 0.001
0.424 2.61 0.0068 0.00085
CONCENTRATION DATA OF THE SAMPLED WASTE
#586 PRODUCING SODIUM BISULFITE
Waste Stream
MBS Sump #1
MBS Sump #2
Mine Oxidation
Pond
Flow
m3/kkg
9.68
9.68
2.77
ZnS04 Pond Effluent 78.54
Lime Treatment
Influent
Truck Washdown
S02 Wastes
Final Treated
TSS COD Zn Cu
kg/kkg kg/kkg kg/kkg kg/kkg
0.191 1.12 0.0067 0.011
0.051 0.455 0.0025 0.00031
2.43 2.33 0.0031 0.00028
11.85 0.759 1.38 0.0022
109.7 10.76 28.55 - 0.0040
0.134
85.86
188.3
0.0117 0.0975 0.00517 2.69xlO~6
1.97 52.5
4.27 21.70
Effluent
555
-------
MR
SUBLIMED
SULFUR
Ul
Ln
CTi
Waste streams sampled.
TO SEHER
COOLING
WASTE
MISCELLANEOUS SODIUM
WASTE I1YKC1ILORITE
OflGANIC
CHEMICAL
WASTES
Figure 24-1. General process flow diagram at Plant #282showing the sampling points.
Sodium Bisulfite Manufacture
-------
AND »2
LTI
LH
Waste streams sampled.
AMINE PLANT
OXIDATION TANK
S3
LIME TREATMENT
AIR
AERATION TANK
PRIMARY SETTLING
14
SO2 AREA DRAINS
TRUCK WASHDOWN
ZnS04 PLANT
WASTE
Zn SETTLING POND
POLISHING
SETTU1NG TANK
OLTIFALL
Figure 24-Z. General fj.ow diagram at Plant K586 showing the sanpling points.
Sodium Bisulfite Manufacture
-------
TABLE 24-8. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WAS1E
STREAMS FOR PLANT #987 PRODUCING SODIUM BISULFITE
Waste Stream Flow
m.3/kkg
No. 1 filter
Floor wash,
etc.
No. 2 Filter
Wash
spills,
Wash
Treatment Influent
(1+2+3)
54 Hour Aeration
Treated Effluent
0
0
0
0
0
0
.051
.0123
.0386
.102
.133
.133
TSS
kg/kkg
0
0
0
0
0
0
.113
.0457
.0052
.315
.375
.0031
COD
kg/kkg
1.
0.
0.
3.
1.
1.
42
299
908
46
19
02
Zn
kg/kkg
7
4
3
2
2
7
.lxlO~5
.4xlO~5
.9xlO~5
.4xlO~4
,4xlO~4
.99xlO~7
Cu
kg/kkg
1.8xlO~5
1.11x10
3.57x10
-5
-5
7.5xlO~5
7.5xlO~
3.6x10"
5
5
558
-------
TO ATMOSPHERE
U1
cn
FILTER WASH
AJKALINE SLURRY
ANHYDROUS SODIUM
BISULFI1E
II AND 13
DRAINS, DRIPS,
SPILLS, WASHDOWNS
OUTFALL TO RIVER
NaOH AIR
Figure 24-3. General process flow diagram ah Plant J987 showing the sanpling points.
Sodium Bisulfite Manufacture
-------
available. The average was
used for tne model plant.
approximately 0.2m3/kkg and this
was
Production - Sodium bisulfite production ranges from 4770
kkg/yr to31,800 kkg/yr at the three plants for which data was
available. The average production is 17,800 kkg/yr. The
production rates at the three plants were used as the model plant
production rates. The operational mode is continuous and is
assumed to run 350 days per year.
Sol id wastes - In the production of sodium bisulfite and
process waslfe(Treatment there is little solid waste generation,
although precipitation of zinc hydroxide may result in small
quantities of filter cake requiring disposal. The model plants
assumed no significant solid waste production.
T
pH to 9-5.
waste. For
to be 0.195
chemicals - Caustic soda is needed to adjust the
The only other requirement is air to oxidize the
the model plant, the caustic soda dosage was assumed
kg//kkg.
24.2 TECHNOLOGY BASED POLLUTION ABATEMENT
24.2.1 Advanced Level Treatment Applications
Priority Pollutants to be Controlled
Priority pollutants should not normally be present in wastes
originating solely from the manufacture of sodium bisulfite from
sodium carbonate and sulfur dioxide. However, it is reported
that some sources of sodium carbonate contain zinc and other
trace metals in measurable amounts. Therefore, a treatment system
to control zinc is proposed. If no zinc is found at a specific
plant, Levels 2 and 3 of the treatment models would not be
necessary.
Dissolved zinc was found in some sodium bisulfite waste
waters during the sampling program. Since no use of zinc was
found in the process, it might be assumed that zinc enters the
waste stream by corrosion of galvanized metals, by coproduct
operations or from nonprocess zinc compounds used by the
industry.
Removal Technologies Available
Zinc is
10.0 or when
can also be
readily
reacted
adsorbed
precipitated at pH values between 8.4_and
with sulfides in various forms. Zinc ions
from clarified solutions by ion exchange
560
-------
resins and precipitated by starch xanthates.
Selection of Appropriate Technology
In addition to controlling zinc, the treatment process
selected must control the COD associated with bisulfites.
BPT (Level lj_ - Batch aeration at pH 9.5 was chosen as the
most cost-effective method of lowering the COD associated with
the primary pollutant, sodium bisulfite. Solution of C02 from
the air during aeration reduces the ph below 9 before discnarge.
Level 2_ - Aerated effluent from the BPT system is
chlorinated to complete COD removal, and is then filtered to
remove finely divided suspended matter carried through or
produced in the BPT system, particularly if zinc is present in
the incoming wastes.
Level 3_ - Ferrous sulfide is applied ahead of the Level 2
dual media filter, to precipitate any residual zinc by the more
effective sulfide process.
Flow Diagrams
Level 1 Figure 24-4
Level 2 Figure 24-5
Level 3 Figure 24-6
Wastes are treated in daily batches, followed by con-
tinuous cumulative aeration and weekly filtration of five
accumulated daily batches, to suit a five-day, 40-hour
production schedule.
Equipment Functions^ - In Level 1, the raw wastes are
received in a one~day holding tank, adjusted to pH 9.5 with
caustic soda and jet aerated by recirculation of the daily batch.
At the end of each day the batch is transferred to a reaction
tank sized for one week's flow, which is continuously aerated by
recirculation tiirough air aspirators. On the sixth day the
aerated weekly batch is discharged directly (Level 1) or tiirough
a dual media filter (Levels 2 and 3). At Level 2 continuous
aeration is terminated early on the sixth day and the weekly
batch is recirculated through the hydraulic eductor of a gas
chlorinator to oxidize any residual COD. At Level 3, ferrous
sulfide is added before filtering, to precipitate any residual
zinc, if COD limits can be consistently met by long-period
aeration, and if zinc is not found in the raw wastes, the
advanced levels of treatment would serve no purpose.
561
-------
en
to
CAUSTIC SODA
RAW
WASTE WATER
AIR
HOLDING
TANK
* EFFLUENT
REACTION TANK
Includes flow monitoring, pH monitoring, and sampler.
Figure 24-4. Waste water treatment Level 1 for sodium bisulfite subcategory - batch
process
-------
Ul
Ch
U)
CAUSTIC SODA
r~
BACKWASH
RAW
WASTE WATER
44-
CHLORINATION
-AIR
HOLDING
TANK
-Qi-
•N-
REACTION TANK
* Includes flow monitoring, pH monitoring, and sampler.
FILTER
EFFLUENT
Figure 24-5. Waste water treatment Level 2 for sodium bisulfite subcategory - batch process.
-------
en
FERROUS
SULFATE
SODIUM
BISULFIDE
CAUSTIC SODA
BACKWASH
CHLORINATION ,
f*" Jj_
-«*
RAW
'1
1
1
t
— . — «- — — ^ N^.
•Q^
X
•*— AIR
-------
Chemicals a_nd_ Hailing - Caustic soda solution, chlorine and
ferroHs suit ide~ are usecT in the treatment processes. Caustic soda
and chlorine, are common industrial chemicals which are fed by
conventional equipment designed to minimize leaks, spills, and
hazards to personnel. Ferrous sulfide is prepared by mixing
ferrous sulfate with sodium bisulfide under well-ventilated
conditions. When the usual precautions are taken in the proper
handling of corrosive and toxic chemicals, there should be no
special problems in applying the proposed technologies.
Separation a_nd_ Removal gjf Sol ids - No solids are formed in
the proposed treatment, with the possible exception of small
amounts of zinc hydroxide and zinc sulfide in the filter
backwash, if zinc should be present in the raw wastes. In that
event, the precipitated solids returned to the holding tank
during backwashing will settle in the hopper bottom of the
reaction tank. As necessary, these solids can be drawn off to a
small earthen drying bed, where liquids will drain into the soil
and the insoluble zinc compounds will remain at the site.
Monitoring Requi rements - Internal process monitoring will
be done with standard field equipment measuring pH, dissolved
oxygen and chlorine. If zinc is present in the raw materials, a
periodic laboratory analysis for zinc should be made on the final
effluent. Monitoring for dissolved sulfide should not be
necessary, since excess sulfide will react with iron from the
ferrous sulfate applied in Level 3, oxidizing to insoluble ferric
sulfide.
24.2.2 Estimated Performance of BPT Systems
Waste waters from the production of sodium bisulfite are
characterized by high concentrations of COD and small flow rates.
The COD load results from the presence of product material in
filter wash waters and general maintenance arid cleanout
operations.
Raw waste loads found in screening and verification were
presented above. The only priority pollutant which might require
regulation is zinc. Although zinc was found in all three of the
plants sampled, its source has not been determined.
BPT technology has been specified as extended aeration to
oxidize COD. This technology should achieve 95 percent removal
of COD. Treated effluent quality and treatment practices at three
plants are presented in Table 24-9.
565
-------
TABLE 24-9. TREATMENT PRACTICES AND VERIFICATION SAMPLING AT SODIUM
BISULFITE PLANTS
Plant Treatment
Treated Effluent
TSS COD zn
rag/1 kg/kkg rag/1 kg/kkg mg/1 kg/kkg
#282 Caustic neutral-
ization sodium
hypochlorite
oxidation
^
#586 Lime pH adjust-
ment aeration,
and settling
159 0.424 979 2.61 2.54 0.0068 2.
22.7 —
115.3
0.059 —
Combined treatment with other process wastes.
566
-------
Base Level Performance Characteristics for Conventional Pollutant
Removal
Based on a 95 percent COD removal efficiency by extended
aeration, implementation of 3PT technology will achieve the
effluent quality presented in Table 24-10.
Base Level Performance for Priority Pollutant Removal
Table 24-10 also presents effluent quality achievable
through implementation of BPT for zinc.
Pretreatment Applications
One plant manufacturing sodium bisulfite presently
discharges to a POTW. Since the major pollutants in this
subcategory, TSS and COD, are compatible with conventional
sewage treatment, BPT technoloy is applicable for pretreatment.
Also, since waste water flow volumes are small in this
subcategoy, limitations for suspended solids can be increased for
pretreatment.
24.2.3 Estimated Performance of Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
Table 24-11 and 24-12 presents estimated achievable effluent
quality through implementation of these technologies.
Pretreatment Applications
As discussed earlier, BPT technoloy is recommended
pretreatment of sodium bisulfite wastes.
:o r
New
Source Applications
Examination of the alternative treatment technologies
proposed for this subcategory has led to the conclusion that
Level 2 technology is applicable to new sodium bisulfite
facilities.
567
-------
TABLE 24-10 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Sodium Bisulfite
Level of Treatment: 1
Waste Water Flow: 0.2 m3/kkg
Pollutant
Subcategory
Per formance
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Aver Max
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
BPT Pollutants:
Total Suspended 23(2)
Solids, TSS
Chemical Oxygen 980(2)
Demand, COD
Proposed Priority
Pollutants
Zinc, Zn 0.2(2)
2.0 37.5 75 0.0075 0.015
2.0 500 1000 0.10 0.20
2.0
0. 5
1.0 0.0001 0.0002
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Verification sampling
568
-------
TABLE 24-11 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Sodium Bisulfite
Level of Treatment: 2
Waste Water Flow: 0.2 m3/kkg
Pollutant
Treatability
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Av e r Max
Emission Limit
(kg/kkg)
30 day 24 hr
Av e r Max
BPT Pollutants :
Total Suspended 15
Solids, TSS
Chemical Oxygen 100
Demand, COD
Proposed Priority
Pollutants
Zinc, Zn 0.4
2.0 15
2.0 100
30 0.003 0.006
200 0.02 0.04
2.0
0.4
0.8 0.00008 0.00016
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
569
-------
TABLE 24-12 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Sodium Bisulfite
Level of Treatment: 3
Waste Water Flow: 0.2 m3/kkg
Pollutant
Treatability
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Av e r Ma x
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
BPT Pollutants;
Total Suspended 15
Solids, TSS
Chemical Oxygen 100
Demand, COD
Proposed Priority
Pollutants
Zinc, Zn
0.2
2.0 15
2.0 100
2.0
0. 2
30 0.003 0.006
200 0.02 0.04
0.4 0.00004 0.00008
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
570
-------
24.2.4 Cost Estimates
Discussion
The cost estimates of three models having different
production levels are presented in Tables 24-13, 24-14 and 24-15.
Annual costs for three treatment levels as a function of
production are shown graphically in Figure 24-7. Treatment cost
oer metric ton of product is shown in Figure 24-3.
Table 24-16 gives a su^iiaary of the unit cost distribution
between afaortization operation and maintenance. Cost components
at various production and levels of treatment are also shown.
Summary
Cost estimates developed for the first level of treatment
indicate that labor and amortization cost has a significant
impact on the total annual costs. At the second and third level
of treatment, for low production, operation and maintenance has
a significant impact on the additional annual costs. At medium
and high production, amortization and operation and maintenance
costs constitute the major portion of the additional costs.
571
-------
TABLE 24-13. MODEL PLANT TREATMENT COSTS
Subcategory SODIUM BISULFITE Type of Regulation BAT
Production 4,770 metric tons per year ( 5,258 tons per year)
13 metric tons per day ( 15 tons per day )
Waste water flow 2.8 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND THIRD
A. INVESTMENT COST
Construction $5,550 $1,650 $1,750
Equipment in place,
including piping,
fittings, electrical
work and controls 47,800 20,500 16,200
Monitoring equipment
in place 9,000
Engineering design
and inspection 12,470 4,430 3,590
Incidentals, overhead,
fees, contingencies... 12,470 4,430 3,590
Land 1,800
TOTAL INVESTMENT COST $89,090 $31,010 $25,130
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $15,000 $1,000 $2,000
Energy 1,600 60 75
Chemicals 400 1,200 1,210
Maintenance 8,729 3,101 2,513
Taxes and insurance... 2,672 930 753
Residual waste
disposal
Monitoring, analysis
and reporting 2,500 1,250 1,250
TOTAL OPERATION AND
MAINTENANCE COST $30,901 $7,541 $7,801
C. AMORTIZATION OF
INVESTMENT COST $14,202 $5,045 $4,088
TOTAL ANNUAL COST $45,103 $12,586 $11,889
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
572
-------
TABLE 24- 14. MODEL PLANT TREATMENT COSTS
Subcategory SODIUM BISULFITE
Production
Type of Regulation BAT
16,900 metric tons per year ( 18,632 tons per year)
48 metric tons per day ( 53 tons per day )
Waste water flow 10 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND THIRD
A. INVESTMENT COST
Construction
Equipment in place,
including piping,
fittings, electrical
work and controls
Monitoring equipment
in place
Engineering design
and inspection
Inc identals, overhead,
fees, conting enc ies...
Land
TOTAL INVESTMENT COST
B. OPERATION AND
MAINTENANCE COST
Labor and supervision.
Energy
Chemicals
Maintenance
Taxes and insurance...
Residual waste
disposal
Monitoring, analysis
and reporting
TOTAL OPERATION AND
MAINTENANCE COST
C. AMORTIZATION OF
INVESTMENT COST
TOTAL ANNUAL COST
$8,500
82,400
9,000
19,980
19,980
1,800
$141,660
$15,000
3,100
1,340
13,986
4,249
2,500
$40,175
$22,755
$62,930
$4,100
37,150
8,250
8,250
$57,750
$1,000
90
2,560
5,775
1,732
1,250
$12,407
$9,395
$21,802
$4,200
28,150
6,470
6,470
$45,290
$2,000
110
2,600
4,529
1,358
1,250
$11,847
$7,368
$19,215
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
573
-------
TABLE 24-15.MODEL PLANT TREATMENT COSTS
Subcategory SODIUM BISULFITE Type of Regulation BAT
Production 31,800 metric tons per year ( 35,059 tons per year)
90 metric tons per day ( 100 tons per day )
Waste water flow 19 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND THIRD
A. INVESTMENT COST
Construction $12,400 $6,250 $6,450
Equipment in place,
including piping,
fittings, electrical
work and controls 123,900 63,700 64,400
Monitoring equipment
in place 9,000
Engineering design
and inspection 29,060 13,990 14,170
Incidentals, overhead,
fees, contingencies... 29,060 13,990 14,170
Land 3,000
TOTAL INVESTMENT COST $206,420 $97,930 $99,190
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $15,000 $1,000 $2,000
Energy 6,200 90 132
Chemicals 2,700 4,840 4,910
Maintenance 20,342 9,793 9,919
Taxes and insurance... 6,192 2,937 2,975
Residual waste
disposal
Monitoring, analysis
and reporting 2,500 1,250 1,250
TOTAL OPERATION AND
MAINTENANCE COST $52,934 $19,910 $21,186
C. AMORTIZATION OF
INVESTMENT COST $33,095 $15,933 $16,138
TOTAL ANNUAL COST $86,030 $35,843 $37,324
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
574
-------
120
no
100
90
LEVELS ±2
11.
o
§80
HEVEI
#1
60
\
50
! !cr
40
! i
30
0 "'15 20 25
PRODUCTION, METRIC TCNS/YEAR x 1000
M
35
Figure 24-7. Variation of annual treatment cost with production for the
Sodium Bisulfite Subcategory
575
-------
12
11
10
•to-
EH
I !
i r
I !
\
\! IV •
\!\
\T\
XT'
X
\L 1EVEILS
I I I
I I !
i i !
10 15 20 25
PRODUCTION, METRIC TONS/YEAR X 1000
Figure 24-8. Variation of annual unit treatment cost with production
(Sodium Bisulfite Manufacture)
576
-------
TABLE 24-16 MODEL PLANT TREATMENT COSTS
Subcategory SODIUM BISULFITE
Type of Regulation BAT
Annual Treatment Costs ($/kkg)
PRODUCTION FLOW
(kkg/yr) (m3/day)
Annual Operation
and Maintenance
Annual
Anortization
Total Cost
4,770
16,900
31,800
4,770
16,900
31,800
4,770
16,900
31,800
3
10
19
3
10
19
3
10
19
FIRST
$
6.48
2.38
1.66
2.98
1.35
1.04
9.46
3.72
2.71
LEVEL OF
SECOND
$
1.58
0.73
0.63
1.06
0.56
0.50
2.64
1.29
1.13
TREATMENT
THIRD
$
1.83
0.81
0.67
1.11
0.57
0.51
2.94
1.38
1.18
FOURTH
$
Not
Applicable
577
-------
SECTION 25
SODIUM HYDROSULFITE
25.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
25.1.1 Industry Profile and Analytical Results
Most of the sodium hydrosulfite produced in the U.S. is sold
in the merchant market. Sodium hydrosulfite is extensively used
in dyeing (cotton) and in the printing industry. It is a
powerful reducing agent and is used in wood pulp bleaching,
reducing, and stripping operations in the food, vegetable oil and
soap industries.
The industry profile data are presented in Table 25-1, while
existing regulations are summarized in Table 25-2.
Priority pollutants found at significant concentrations in
the raw waste during screening at Sodium Hydrosulfite - Formate
Process Plant #672 were as follows:
Maximum Concentration Observed
Pollutant ug/1
Cadmium 43
Chromium 9300
Copper 1450
Lead 1294
Nickel 1665
Silver 128
Zinc 27412
Pentachlorophenol 373
Phenol 160
Cyanide 101
Mercury 28
Selenium 34
The plant was sampled using verification procedures. No
Plants were visited during the verification phase of the study.
578
-------
TABLE 25-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
SODIUM HYDROSULFITE (FORMATE PROCESS)
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
40,340 kkg/year
39,940 kkg/year
2
1
20,450 kkg/year
20,450 kkg/year
50 percent
51 percent
100 percent
273 cubic meters/day
4.68 cubic meters/kkg
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
579
-------
TABLE 25-2 - EXISTING REGULATIONS - EFFLUENT KCMTTATICN GUIDELINES
SUBCftlEGORY Sodium Hydrosulf ite
SUBPART BE (40CFR 415.570, 5/22/75)
STANDARDS
BPCTCA BATEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/1) (mg/1) Cmg/1) Cmg/1)
Sodium
Hydro- Reserved Reserved Reserved Reserved
Sulfite
= Maximum of any one day.
Avg. = Average of daily values for thirty consecutive days shall not exceed.
580
-------
A summary of daily and unit product raw waste
plant sampled can be found in Table 25-3.
loads for the
Based on the toal annual production of sodium hydrosulfite
by the formate process and the average waste load generated per
unit product, the estimated total priority pollutant waste loads
generated each year for this particular process subcategory are
as follows:
Pollutant
Waste Load (kg/year)
Cadmium 2.8
Chromium 5,590
Copper 76
Lead 28
Nickel 108
Silver 3.2
Zinc 440
Pentachlorophenol 28
Phenol 12
Cyanide 2.8
Mercury 0. 26
Selenium 2.4
25.1.2 Process Waste Sources and Waste Water Treatment Data
General Process Description
Raw
hyd rosulfite Ts
sodium hydroxide
presence
reaction is
materials_ and process - In the formate process, sodium
produced By reacting sodium formate solution,
solution and liquid sulfur dioxide in the
of a recycled stream of methanol solvent. The general
2HC02Na + 3NaOH + 3S02 = Na2S204 + NaHCOS + Na2S03 + CO + 2H20 (1)
The operation occurs in several steps:
1. An aqueous solution of sodium formate is prepared and introduced
into the reactor.
2. The recycled stream of methanol containing sulfur dioxide is
introduced into the reactor.
3. The sodium hydroxide and sodium formate solutions, liquid sulfur
dioxide, and recycled methanol are then contacted under pressure
581
-------
25-3. SUMMARY OF RAW. V3ASTE LOADINGS FOUND AT A SODIUM HYDROSULFITE
PLANT (FORMATE PROCESS)
- — — -~ ~~~
pollutant
Priority
Cadmium, Cd
Chromium, Cr
Copper, Cu
Lead, Pb
Nickel, Ni
Silver, Ag
Zinc, Zn
Pentachlorophenol
Phenol
Conventional
TSS
COD
Loadings
kg/day
Average
0.0041
0.81
0.11
0.041
0.16
0.0045
0.63
0.04
0.017
91.6
1687
kg/kkg
Average
0.00007
0.14
0.0019
0.0007
0.0027
0.00008
0.011
0.0007
0.0003
1.57
28.9
582
-------
at slightly elevated temperatures.
Sodium hydrosulfite then precipitates and forms a slurry in
the reactor. The coproduct, sodium sulfite, and sodium
bicarbonate and carbon monoxide gas are formed.
There is a small amount of methyl formate produced in the
reactor as a side reaction between the sodium formate and
methanol:
HC02Na + CH30H = HC02CH3 + NaOH (2)
This side reaction product remains in the recycling methanol
during the entire process. As a result, some of the methanol
must be periodically purged from the recycle system to avoid
excessive buildup of this impurity.
The resulting slurry of sodium hydrosulfite in the solution
of methanol, methyl formate and coproducts is sent to a
pressurized filter operation which recovers the crystals of
sodium hydrosulfite. The crystals are dried in a steam heated
rotary drier, recovered and packaged. The filtrate and backwash
liquors from the filter operation are sent to the solvent
recovery system as is the vaporized methanol from the drying
operation. The drying of the sodium hydrosulfite filter cake
must be done very carefully as it is heat sensitive and tends to
decompose to sulfite.
A general process flow diagram for Plant #672 can be found
in Figure 25-1.
Water Use and Waste Source Inventories
Water use - Water is used in the process as make up for the
reaction solutions and for steam generation in the rotary dryers.
Water is also used for noncontact cooling in the reactor gas vent
scrubbers and dryers, as well as pump seals and washdowns.
Sources of waste water
A. The strongest process waste is the aqueous residue from
the distillation column bottoms (solvent recovery system). This
waste contains concentrated reaction coproducts and is purged
from the system at a rate of approximately 14,000 GPD. At plant
#672 this waste is sent to a coproduct pond where it is held and
either sold to the pulp and paper industry or bled into the
treatment system.
583
-------
GASEOUS
CCHPRDDUCTS
VINT GRS
SCRUBBER
LIQUID SULFUR DIOXIDE
SODIUM FOFMATE SOLUTION
SODIUM HYDROXIDE SOLUTION
. RECYCLED HETHANOL, SO., AND
REflCTOR
METHYL FORMATE
Ul
00
FILTER
. FILTRATE
./ AND
BACKWASH
LIQUOR
SODIUM HYDRDSULFITE
CRYSTALS
DISTILLER
COLUMN
(SOLVENT
RECOVERY)
DISTILLER COLUMN BOTTOMS
iCO-PRODUCT WASTES TO POND)
VAPORIZED
MBTHANOL
DRYER
DRIED PRODUCT
Figure 25-1. General process flow diagram at Plant J672
Sodium Hydrosulfite Manufacture
-------
B. The dilute wastes from process are contributed fron
leaks, spills, washdowns, and tank car washing. At Plant #672,
this is collected in a sump and then sent to the biological'
treatment system.
C. Cooling tower and boiler blowdown constitutes a
noncontaminated waste water source. This is sent to the final
compartment of the chlorine contact tank, without treatment for'
discharge with the combined effluent of the treatment plant.
D. The vent gas scrubbers create a waste water source which
is sent to the methanol recovery distillers for recycle. This
waste eventually goes to the coproduct pond with the distilling
column bottoms.
A general flow diagram of Plant #672 showing process waste
sources and sampling points is shown in Figure 25-2. The sources
of waste water for each sampling point are as follows:
1. Coproduct pond.
2. Dilute waste from sodium hydrosulfite process area
at sumps.
3. Combined influent to treatment. This point collects
waste from points 1 and 2, plus the sodium bisulfite
waste stream.
4. Treated effluent at the outfall.
A tabulation of raw waste flows, concentrations and loadings
for the two waste steams to treatment at Plant #672 can be found
in Table 25-4.
Control and Treatment Practices
The Best Practical Technology for sodium hydrosulfite waste
treatment is equalization, aeration (biological oxidation)
clarification and final settling and equalization prior to
d ischarge.
Treatment practices - The only plant visited during the
screening program was Plant #672. Verification sampling
procedures were used. Because of the nature of the two waste
streams, each one is handled differently. The dilute waste is
first sent to a holding pond where the flow equalized and the
waste mechanically aerated. This pond also contains
approximately 1500 gallons per day of waste from a sodium
bisulfite process. The pond effluent is pH adjusted with
sulfuric acid and sent to an aeration basin. A
nitrogen-phosphate fertilizer and urea are added here for
nutrients. Approximately 3500 gallons per day of sanitary waste
and up to 25,900 gallons per day of clean dilution water are also
added to the aeration basin. This basin formerly had mechanical
aerators, but now has air diffusers which allow better
585
-------
Ln
oo
CTi
SODIUM HYDROXIDE
SODIUM
BISUIFITE
WASTE
'13
LINE
' TO CONCENTRATOR
COOLING TOWER
AND BOILER SLOWDOWN
SANITARY WASTE
WASTE SIUDGE
DISCHARGE
I- _ _ _ _L
Waste streams sampled
Figure 25-2. General process flow diagram at. Plant. 1771 showing the sampling points.
Sodiun Hydrosulfite Manufacture
-------
TABLE 25-4. FLOW AND POLLUTANT CONCENTRATION DATA OF THE SAMPLED WASTE
STREAMS FOR PLANT #672' PRODUCING SODIUM HYDROSULFITE
Parameter
Stream #1 (Coproduct) Stream #2 (Dilute Waste)
Flow m /kkg
Pollutant
Chemical Oxygen
Demand, COD
Total Suspended
Solids, TSS
Zinc, Zn
0.91 1.87
mg/1 kg/kkg mg/1 kg/kkc
77,922 70.9 14,628 27.4
61
24
0.056
0.022
263
0.77
0.49
0.0014
All values are averages of three days of sampling.
587
-------
temperature control for biological oxidation. The effluent from
aeration goes to a clarifier. Approximately 14,000 gallons per
day of the settled sludge is returned to the aeration basin and
2400 gallons per day is sent to drying piles on site. More
dilution water is added to the clarifier when needed for TDS
control. The overflow from the clarifier goes to a chlorine
contact tank because of the sanitary waste. The blowdown water
from the cooling tower and boilers is added to the final chamber
of the chlorine contact tank. The effluent from this unit is
sent to a final polishing pond for settling and equalization
before discharge.
The coproduct waste from the distilling column bottoms is
sent to a lined coproduct pond at a rate of 14,000 gallons per
day and held for one of two possible disposal methods. When
there is a market for the coproducts, the waste is concentrated
and sold to the pulp and paper industry. At times when this is
not possible, and the pond reaches near capacity, the waste is
bled into the treatment system described above through the dilute
waste holding pond.
A general flow diagram of the biological treatment system is
also included in Figure 25-2.
Table 25-5 shows the total combined input to the treatment
system, the treated effluent quality and efficiency of the
system.
Evaluation of Production and Waste Flow Data
Only two plants utilize the formate process in this
subcategory. Data from the one plant sampled can be considered
representative of this process for both plants. The other plant
in this subcategory has an identical, though slightly smaller,
production process. However, the waste treatment system is
different, and on a larger scale, due to the large loadings of
waste from several other products. Because of the large product
mix, representative treatment data for sodium hydrosulfite waste
water only cannot be analyzed for this plant. Plant £672 was
visted for this reason.
Table 25-5 shows that the treatment efficiency for chemical
oxygen demand removal is 95.2 percent and total suspendend solids
removal is 97 percent. Zinc is shown here, having the highest
concentration of several metals found at significant levels, with
a removal of almost 98 percent. The higher effluent flow is due
to the addition of the sanitary waste, dilution water, and
cooling tower and boiler blowdown to the treatment system. These
sources should have little or no effect on the analyzed and
calculated values for treatment plant efficiencies. At the time
screening sampling was conducted at Plant #672, none of the
588
-------
TABLE 25-5. INFLUENT AND EFFLUENT QUALITY AND EFFICIENCY FOR PLANT #672
WASTE WATER TREATMENT SYSTEM FOUND DURING SCREENING SAMPLING
Parameter
Stream #3
(Raw Influent)
Stream #4 % Removal
(.Treated Effluent)
Flow m /kkg
Pollutant
Chemical Oxygen
Demand, COD
Total Suspended
Solids, TSS
Zinc, Zn
1.87
mg/1 kg/kkg
15,487
843
5.85
29.0
1.58
0.011
4.68
mg/1 kg/kkg
740 3.46 95.2%
25 0.12 97.0%
0.122 0.00057 97.91
Higher flow due to the addition of Sanitary Waste and Dilution Water to the
aeration basin plus cooling tower and boiler blowdown to the chlorine
contact tank.
All values are an average of three days of sampling.
589
-------
coproduct waste water was being sent to the biological treatment
system. As a result, the sodium hydrosulfite process waste being
treated was from the dilute waste area only.
Model Plant and BPT Treatment System Specifications
The specifications of the waste input parameters and the
design of the model plant BPT level treatment system are based on
the foregoing information presented on Plant #672.
In this subcategory, commercial fertilizer and urea are
added to stimulate growth of the biomass employed in biological
treatment, and not for direct reaction with a residual pollutant.
Therefore, the chemicals used to not bear a fixed
relationship to the plant production in units of sodium
hydrosulfite.
Organic solids generated in the model treatment system are
assumed to be disposed of on land at the site, without a separate
cost for sludge disposal.
25.2 TECHNOLOGY BASED POLLUTION ABATEMENT
25.2.1 Advanced Level Treatment Appl ications
Priority Pollutants to be Controlled
Although sodium hydrosulfite is being manufactured by both
the zinc process and the formate process, the trend is away from
the zinc process for environmental reasons. This discussion
concerns only the formate process, using a sodium formate feed
stock from a source which appears to contain significant heavy
metal impurities, (chromium, zinc, nickel, lead and copper) as
well as trace amounts of cyanide. A predominant characteristic
of sodium hydrosulfite waste is their high chemical oxygen demand
resulting from various forms of sulfite, from methyl formate and
from residual methanol after a solvent recovery process. Low
levels of phenolic compounds are also found in the raw wastes.
In this subcategory an exception is made to the assumed
exclusion of sanitary sewage from the waste stream. To utilize
the nutrients and bacteria present in sewage as support for a
biological oxidation system to control organics and COD, the
Plant sanitary wastes are included in the biological treatment.
The significant heavy metals appear largely in a coproduct
waste stream which is often sold for use in the pulp and paper
590
-------
industry. When no market exists, these wastes are bled into the
product wastes. To provide the capability for treating the
co-product wastes, the model plant design flow and pollutant load
are based on continuous treatment of combined wastes.
Two levels of treatment are proposed, in order to deal with
the priority pollutants which were found in the wastes of one
plant sampled during the verification phase.
Removal Technologies Available
Practical technologies for controlling COD include various
forms of mechanical and biological oxidation. For the relatively
simple chemical oxidation of sulfite to sulfate, intimate contact
with atmospheric oxygen is effective, using submerged air
diffusers, induced air in a circulating system or mechanical
surface aeration. For biochemical oxidation of resistant
organics such as formates, phenols, chlorinated hydrocarbons, and
methanol, trickling filtration, rotating biological discs or
variations of the activated sludge process can provide intimate
contact between organic pollutants and the microbiological
organisms which use them as food.
Technologies for controlling heavy metals include alkaline
precipitation, which is effective for the common heavy metals,
and sulfide treatment, which precipitates nickel, zinc and
copper, but does not control chromium without a subsequent pH
increase. Other less appropriate metal removal techniques have
been discussed under other subcategories.
Selection of Appropriate Technology
BPT (Level JJ_ - In the treatment system pH adjustment,
biological oxidation, settling and chlorination are used to
reduce COD and coliform organisms in the combined wastes, in
accordance with existing plant practice.
Level 2_ - The coproduct wastes are separately subjected to
alkaline precipitation, to remove the toxic heavy metals and
reduce arsenic, and then are combined with the product wastes for
biological oxidation treatment and chlorination, as in Level 1.
If an actual formate process plant employs metal-free sodium
formate in its process there is no reason to expect heavy metals
in the process wastes and Level 2 treatment should not be
necessary.
591
-------
Flow Diagrams
BPT (Level 1) Figure 25-3
Level 2 Figure 25-4
Equipment Functions - Combined product and coproduct wastes
are received in a mixed and aerated equalizing basin, adjusted to
a neutral pH and aerated in a 4 day aerated lagoon, including 50
percent return of underflow to the influent. Plant sewage,
nutrients and diluting water are added to the lagoon to promote
biological oxidation of COD and organics. Lagoon effluent is
clarified, chlorinated and sent to a polishing pond before
discharge through effluent monitoring facilities. Cooling tower
and boiler blowdown wastes enter the system after chlor ination,
since they require no treatment except settling of scale and
inert debris in the polishing pond. Floating aerators are used
in the equalization basin and compressed air is diffused in the
aerated lagoon, for mixing and introduction of dissolved oxygen
into the mixed liquor.
In the Level 2 treatment model , coproduct wastes are
received in a separate 18-hour aerated and recirculated holding
tank, which is pumped at average daily flow to a gravity
clarifier, adding sufficient lime to reach a pH of 10.5. The
clarifier overflow joins the product waste stream in the
equalization basin of the BPT system. All features of the BPT
system remain the same, since it was originally sized to handle
the combined wastes.
Chemicals and handling - Sulfuric acid, lime, filter aid and
chlorine are chemicals commonly used in waste treatment. When
handled in corrosion resistant equipment designed for their use,
no unusual hazards are expected. Raw sewage and 10-10-10 liquid
fertilizer introduced into the aerated lagoon become thoroughly
mixed and are eventually consumed in the biological oxidation
process, constituting no threat to operating personnel.
Chlorine, used for control of coliform bacteria, is received in
ton containers and applied as a chlorine water solution using
standard solution feed chlorination equipment. There are no
unusual chemical handling problems in treating these wastes,
provided the waste streams are kept at a neutral or alkaline pH.
Separation and disposal of: solids - In the BPT system, waste
activated sludge~io~l ids are assumed to be dried in sludge beds at
the site, to be used as fertilizer for plant landscaping.
Clarifier underflow from alkaline precipitation of coproduct
waste in Level 2 is assumed to be sent to a sludge holding tank
and dewatered at suitable intervals in a filter press, followed
by hauling of solids to a chemical landfill. Filter press
filtrate is returned to the holding tank for retreatment.
592
-------
a
COOLING TOWER AND
BOILER SLOWDOWN
U1
U3
A
PRODUCT AND
CO-PRODUCT \_
WASTE WATER
EQUALIZATION
*—WASTE SLUDGE
RECIKCULATION
Includes flow monitoring, pH nonitoring and sampler.
Figvire 25-3. Waste water treatment level 1 for sodiim hydrosulfite.
-------
PRODUCT
WASTE
WATOR
e
SLUDGE
HOLDING
ACID
SEWAGE
LANDFILL
EQUALIZATION
'4
i
NUTRIENT DILUTION WATER
e
1 * r
\ / *ff
AERATED LAGOON
J
\
CHLORD1ATION
CLARIFIER
O-A
COOLING
TOWER
AND
BOILER
BTjOWDOWN
POLISHING POND
-6»- WASTE SLUDGE
EFFLUENT
RBCIRCUIATION
Includes flow monitoring, pll monitoring and saiipler.
Figure 25-4. Waste water treatment Level 2 for sodium hydrosulfite.
-------
Monitoring requirements - Internal monitoring should include
simple field tests for pH, chlorine residual and settleable
solids. Maintenance of the co-product stream clarifier at a pH of
10.5 is expected to provide control of heavy metals without need
for routine metal analyses, but effluent samples should be
analyzed for chromium, zinc, copper, nickel and lead by atomic
absorption for offical reporting purposes, in addition to
periodic COD tests for general evaluation of the treatment.
25.2.2 Estimated Performance of BPT Systems
Raw waste loads found at Plant
The organic priority pollutants
#672 were presented above.
found were phenol and
pentachlorophenol. Priority pollutants which might require
regulation are chromium and zinc. Waste water treatment at Plant
#672 consists of equalization, aeration in a biological oxidation
pond, clarification, chlorination and settling prior to
discharge. Table 25-6 presents the results of sampling treatment
influent and effluent. At the time of sampling, coproduct waste
was not being treated.
BPT technology has been specified as the technology
presently in use at Plant #672. Design and cost estimates are
based on inclusion of coproduct wastes.
Base Level Performance Characteristics for BPT Pollutant Removal
Table 25-7 presents effluent quality achievable through the
implementation of BPT technology.
Base Level
Removal
Performance Characteristics for Priority Pollutant
Priority pollutants, both metals and organics, are being
reduced to acceptable levels with the present BPT system.
Reduction of metals is assumed to be coincidental; the metals are
perhaps precipitating as carbonates. No estimate can be made of
the achievable effluent quality for metals, when an additional
load of metal-bearing waste water is discharged from the
coproduct pond.
Pretreatment Applications
No formate process sodium hydrosulfite plant
discharges to a POTW. BPT technology would be
however, should such a discharge occur in the future.
presently
applicable
595
-------
25-6. SCREENING RESULTS FROM SODIUM HYDRDSULFITE PLANT #672
Pollutant
Flow (m /kkg)
Chemical Oxygen
Demand, COD
Total Suspended
Solids, TSS
Zinc, Zn
Chromium, Cr
Copper, Cu
Lead, Pb
Nickel, Ni
Cadmium, Cd
Phenol
Pentachlorophenol
Raw Waste Influent
ing/1 kg/kkg
1.87
15,500
840
29.0
1.58
Treated Effluent
mg/1 ^ kg/kkg
4.68
740
25
3.46
0.12
5.8
7.4
1.0
0.83
1.4
0.037
0.15
0.37
0.011
0.014
0.0019
0.0015
0.0027
0.000069
0.0003
0.0007
0.12
<0.043
0.028
0.07
0.16
0.029
<0.01
<0.01
0.00057
<0.0002
0.00013
0.00013
0.00075
0.00014
<0. 00005
<0. 00005
Higher flow due to the addition of sanitary wastes and dilution water to
the aeration basin, plus cooling tower and boiler blowdown to the chlorine
contact tank.
596
-------
TABLE 25-7 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Sodium Hydrosulfite
Level of Treatment: 1
Waste Water Flow: 4.7 m3/kkg
Quality Limit Emission Limit
Subcategory (1) (mg/1) (kg/kkg)
Pollutant Performance VFR
(mg/1) 30 day 24 hr 30 day 24 hr
Aver Max Aver Max
BPT Pollutants;
Total Suspended 25(2) 2.0 37.5 75 0.18 0.36
Solids, TSS
Chemical Oxygen 740(2) 2.0 1000 2000 4.7 9.4
Demand, COD
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
(2) - Verification sampling
597
-------
25.2.3 Estimated Performance g_f Advanced Level Systems
Advanced Level Performance Estimates for BPT and Priority
Pollutant Removal
No improvement in effluent quality with regard to
conventional pollutants is expected with this advanced
technology. But effluent quality in terms of priority metals
will be controlled to the levels indicated in Table 25-8.
New Source Applications
The advanced control and treatment technology is recommended
for new formate process sodium hydrosulfite facilities as NSPS.
However, BPT technology would be applicable when a market is
available for the coproduct stream.
25.2.4 Cost Estimates
Discussion
The cost estimate of one model plant having two levels of
treatment and the same level of production at both the levels is
presented in Table 25-9. Table 25-10 gives a summary of the unit
cost distribution between amortization operation and maintenance
cost components at two levels of treatment.
Summary
Cost estimates developed for the first and the second levels
of treatment indicate that labor and supervision costs constitute
a major portion of the annual cost. This reflects the manpower
requirements for operating the treatment systems on a 24-hour
basis.
598
-------
TABLE 25-8 CONTROL PARAMETER LIMITATIONS
SUBCATEGORY: Sodium Hydrosulfite
Level of Treatment: 2
Waste Water Flow: 4.7 m3/kkg
Pollutant
Performance
(mg/1)
Quality Limit
(1) (mg/1)
VFR
30 day 24 hr
Av e r Max
Emission Limit
(kg/kkg)
30 day 24 hr
Aver Max
BPT Pollutants;
Total Suspended 25
Solids, TSS
Chemical Oxygen 1000
Demand , COD
Proposed Priority
3.0
37.5
2.0 1000
112 0.18 0.53
2000 4.7 9.4
Pollutants
Zinc, Zn
Chromium, Cr
0.5
0.1
2.0
2.0
0.5
0. 1
1.0 0.0024 0.0047
0.2 0.0005 0.0009
(1) - VFR: ratio of the 24 hour variability factor to the
30 day variability factor.
599
-------
TABLE 25-9. MODEL PLANT TREATMENT COSTS
Subcategory SODIUM HYDROSULFITE Fonnate Process Type of Regulation BAT
Production 20,450 metric tons per year ( 22,546 tons per year)
58 metric tons per day ( 64 tons per day )
Waste water flow 273 cubic meters per day.
LEVEL OF TREATMENT*
FIRST SECOND
A. INVESTMENT COST
Construction $51,000 $11,500
Equipment in place,
including piping,
fittings, electrical
work and controls 113,000 110,200
Monitoring equipment
in place 9,000
Engineering design
and inspection 34,600 24,340
Incidentals, overhead,
fees, contingencies... 34,600 24,340
Land 12,000 2,400
TOTAL INVESTMENT COST $254,200 $172,780
B. OPERATION AND
MAINTENANCE COST
Labor and supervision. $168,000 $84,000
Energy 12,000 1,200
Chemicals 3,500 18,500
Maintenance 24,220 17,038
Taxes and insurance... 7,626 5,183
Residual waste
disposal 2,500
Monitoring, analysis
and reporting 15,000 7,500
TOTAL OPERATION AND
MAINTENANCE COST $230,346 $135,921
C. AMORTIZATION OF
INVESTMENT COST $39,405 $27,720
TOTAL ANNUAL COST $269,751 $163,641
*First level represents the base cost of treatment system.
Other levels represent the incremental cost above base cost.
600
-------
TABLE 25-10 MODEL PLANT TREATMENT COSTS
Subcategory SODIUM HYDROSULFITE Formate Process Type of Regulation BAT
PRODUCTION FLOW
(kkg/yr) (m3/day)
Annual Treatment Costs ($/kkg)
FIRST
$
LEVEL OF TREATMENT
SECOND
$
THIRD
$
FOURTH
$
Annual Operation
and Maintenance
Annual
/Amortization
Total Cost
20,450 273 11.26 6.65 Not Applicable
20,450 273 1.93 1.36
20,450 273 13.19 8.00
601
-------
SECTION 26
HYDROCHLORIC ACID INDUSTRY
26.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
26.1.1 Industry Profile and Analytical Results
Most of the hydrochloric acid is produced as a by-product in
the manufacture of chlorinated organic compounds. It is used in
oil well activation, pickling of steel, metal cleaning, in
monosodium glutamate manufacture and starch hydrolysis. It is
also used as an acid reagent in several chemical manufacturing
processes.
The industry profile data for this subcategory are given in
Table 26-1, while existing regulations are summarized in Table
26-2.
Priority pollutants found in the raw waste during screening
at Hydrochloric Acid Plant #014 were as follows:
Maximum Concentration Observed
Pollutant ug/1
Lead 3.5
Mercury 2
Nickel 5.5
On the basis of these findings, this subcategory has been
recommended as an exclusion candidate under Paragraph 8.
602
-------
TABLE 26-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
HYDROCHLORIC ACID
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
2,270,000 kkg/year
83
20
755,000 kkg/year
567,000 kkg/year
25 percent
4 years
49 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
603
-------
26-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
Hydrochloric Acid
SUBPAKT G (40CFR 415.70, 5/22/75)
STANDARDS
BPCTCA* BATEA* NSPS*
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/1) (mg/D (mg/1) (mg/1)
Hydrochloric No discharge No discharge No discharge
Acid of pwwp 3 of pwwp of pwwp
*
Sections 415.72, 415.73, and 415.75 were remanded and are presently
reserved (41 FR 51601, November 23, 1976) .
raax, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants.
604
-------
SECTION 27
NITRIC ACID INDUSTRY
27.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
27.1.1 Industry Profile and Analytical Results
Most of the nitric acid produced is used in the manufacture
of ammonium nitrate and other nitrogen fertilizers. On site
captive use is extensively practiced. It is also used in the
manufacture of explosives, plastics and other organic products.
Other uses are as an acidic and pickling agent.
The industry profile data for this subcategory are given in
Table 27-1, while existing regulations are summarized in Table
27-2.
Priority pollutants found in raw wastes during sampling were
as follows:
Maximum Concentration Observed
ug/1
Pollutant Screening Verification
(2 Plants) (1 Plant)
Chromium
Zinc
Lead
Mercury
Silver
2-4 Dinitrophenol
Nickel
Cyanide
110
120
29
.47
.5
215
170
<.04
100
791
<10
4.5
<15
Not analysed
85
<.02
The 2-4 Dinitrophenol is presumed to be from comtamination
by the organic products manufactured at the plant, and not
process related. The chromium and zinc are due to cooling water
conditioners present in the blowdown which is mixed with process
streams.
It has been recommended that this subcategory be included in
the fertilizer industry guidelines.
605
-------
TABLE 27-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
NITRIC ACID
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total "capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
9,177,000 kkg/year
7,171,000 kkg/year
87
11
1,106,000 kkg/year
774,400 kkg/year
12 percent
11 percent
4 years
83 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
606
-------
TABLE 27-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SUBCAIEGORY Nitric Acid
SUBPART J (40CFR 415.100, 3/12/74)
' STANDARDS
BPCTCA* BATEA* NSPS*
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (rng/1) (mg/1) (mg/1) (mg/D (mg/1)
Nitric No discharge No discharge No discharge
Acid of pwwp 3 of pwwp of pwwp
Sections 415.102, 415.103, and 415.105 were remanded and are presently
-.reserved (41 FR 51601, November 23, 1976) .
wax, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants.
607
-------
SECTION 28
SODIUM CARBONATE INDUSTRY
(SOLVAY PROCESS)
28.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
28.1.1 Industry Profile and Analytical Results
On-site captive production of sodium carbonate (soda ash) is
a dominant practice. Sodium carbonate is used in the manufacture
of sodium bicarbonate, ammonium chloride and calcium chloride.
The industry profile data are given in Table 28-1, while
existing regulations are summarized in Table 28-2.
Priority pollutants found in significant concentrations in
the raw waste during screening of Sodium Carbonate Plant #261
were:
Pollutant Concentration ug/1
Antimony 430
Beryllium 220
Lead 2700
Thallium 200
Zinc 750
Silver <57
Plant #261 is the only plant that is operating using this
process. It does not appear likely that more plants of this type
will be constructed since there is a lower cost, cleaner process
available. The sources of priority pollutants, particularly
lead, is under investigation. Because of the nature of this
industry, it has been recommended that this subcategory be
further studied under Phase II.
603
-------
TART.71 28-1 SUBCATEGORy PROFILE DATA SUMMAEY
SUBCAIEGORY SODIUM CARBONATE
Total subcategory capacity rate 8,650,000 kkg/year
Total subcategory production rate
Number of plants in this subcategory 10
308 Data on file for 8
With total capacity of 3,629,000 kkg/year
With total production of 2,828,000 kkg/year
Representing capacity 42 percent
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum 10 years
Maximum 95 years
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
609
-------
TABLE 28-2 - EXISTING REGULATIONS .- EFFLQEtSTT LIMITATION GUIDELINES
SUBCAiEGORY Sodium Carbonate
SUBPAKT 0 (40CFR 415.150, 3/12/74)
STANDARDS
Product
Process
Sodium
Carbonate
Para-
meters
TSS
BPCTCA*
1 2
Max. Avg.
kg/kkg k/kkg
(mg/1) (mg/1)
0.20
(222.2)**
0.10
(111.1)
BATEA*
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
0.34 0.17
NSPS*
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
No discharge
of pwwp 3
*
Sections 415.152, 415.153, and 415.155 were remanded and are presently
, reserved (41 FR 51601, November 23, 1976).
wax, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants,
**flow basis 900 1/kkg.
610
-------
SECTION 29
SODIUM METAL INDUSTRY
29.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
29.1.1 Industry Profile and Analytical Results
Sodium metal is manufactured with chlorine by electrolysis
of fused salt. It is used in the production of tetraethyl lead
gasoline additives, sodium cyanide, sodium peroxide, and titanium
and zirconium metals. In liquid form, it is used as a nuclear
reactor coolant; it is also used as a light, thermally conductive
solid in various applications.
The industry profile for this subcategory is given in Table
29-1, while existing regulations are summarized in Table 29-2.
No priority pollutants were found at significant
concentrations during screening of Sodium Metal Plant #339. On
the basis of these findings, this subcategory has been
recommended as an exclusion candidate under Paragraph 8.
611
-------
29-1 SUBCATEQOEY .PROFILE DATA SUMMARY
SUBCATEGORY SODIUM METAL
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory 5
308 Data on file for 2
With total capacity of 332,000 kkg/year
With total production of 300,000 kkg/year
Representing capacity 88 percent
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
612
-------
TABLE 29-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SUBCATEGORY Sodium Metal
SUBPART R (40CFR 415.180, 3/12/74)
STANDARDS
BPCTCA * BATEA* NSPS*
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (n*g/D (mg/1) (rag/1)
Sodium „,„,; n .., n --, No discharge No discharge
Metal of pwwpj of pwwp
Sections 415.182, 415.183, and 415.185 were remanded and are presently
reserved (41 FR 51601, November 23, 1976).
wax, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants.'
613
-------
SECTION 30
SODIUM SILICATE INDUSTRY
30.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
30.1.1 Industry Profile and Analytical Results
Sodium silicate is manufactured both in liquid and anhydrous
powdered form. It has many industrial uses, such as additives in
adhesives, flocculants, and cleaning agents. It is also used in
the production of soap and household detergents.
The industry profile for this subcategory is given in Table
30-1, while existing regulations are summarized in Table 30-2.
Priority pollutants of significance found in the effluent
during screening at Sodium Silicate Plant #807 were as follows:
Pollutant Concentration (ug/1)
Nickel 121
Silver 1.3
Mercury 1.3
Due to the low waste loads generated by this industry, this
subcategory has been recommended as an exclusion candidate under
Paragraph 8.
614
-------
TABLE 30-1
SUBCATEQORY PROFILE DATA SUMMARY
SUBCATEGORY
SODIUM SILICATE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
814,000 kkg/year
679,000 kkg/year
30
7
300,700 kkg/year
254,900 kkg/year
37 percent
37 percent
12,400 kkg/year
57,300 kkg/year
7 years
43 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
615
-------
30- Z - EXISTING REGULATICMS - EFFLUENT LIMITATION GUIDELINES
SUBCATEGORY Sodium Silicate
SUBPAKT S (40CFR 415.190, 3/12/74)
STANDARDS
BPCTCA* BAIEA * NSPS *
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
Sodium „,,,., n n, n nnc No discharge No discharge
U • U-L U • UUD "
_ t T . . XOO U • U-L U • UUD ,- "5 j~
Silicate of pwwp3 of pwwp
*
Sections 415.192, 415.193, and 415.195 were remanded and are presently
.reserved (41 FR 51601, November 23, 1976).
wax, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants,
616
-------
SECTION 31
SULFURIC ACID INDUSTRY
31.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
31.1.1 Industry Profile and Analytical Results
Sulfuric acid is one of the most extensively used of all
manufactured chemicals. The major industrial use is in the
fertilizer industry, with on-site captive use of the product as a
dominant practice. It is also used in the manufacturing of
plastics, explosives, detergents, hydrofluoric acid, nuclear fuel
and several other organic and inorganic products.
The industry profile data for this subcategory are given in
Table 31-1, while existing regulations are summarized in Table
31-2.
No priority pollutants were found at significant
concentrations in the raw waste during screening of Sulfuric Acid
Plant #363. On the basis of these findings, this subcategory has
been recommended as an exclusion candidate under Paragraph 8.
617
-------
TABLE 31-1 - SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEQORY
SULFURIC ACID
Total subcategory capacity rate 42,144,000 kkg/year
Total subcategory production rate 30,464,000 kkg/year
Number of plants in this subcategory 151
308 Data on file for 47
With total capacity of 8,800,000 kkg/year
With total production of 6,300,000 kkg/year
Representing capacity 21 percent
Representing production 21 percent
Plant production range:
Minimum 5,300 kkg/year
Maximum 47,700 kkg/year
Average production
Median production
Average capacity utilization
Plant age range:
Minimum 3 years
Maximum 78 years
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
618
-------
TABLE 31-2 - EXISTING REGULATIONS - EFFLUENT LIMITATICN GUIDELINES
SUBCATEGORY Sulfuric Acid
SUBPART U (40CFR 415.210, 3/12/74)
' STANDARDS
BPCTCA* BMEA* NSPS*
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
Sulfuric No discharge No discharge No discharge
Acid of pwwpr of pwwp of pwwp
Sections 415.210, 415.212, 415.213, and 415.215 were remanded are are
^presently reserved (41 FR 51601, Novennber 23, 1976) .
Max, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants,
619
-------
SECTION 32
AMMONIUM CHLORIDE INDUSTRY
32.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
32.1.1 Industry Profile and Analytical Results
Most ammonium chloride is produced as a by-product in the
manufacturing of sodium carbonate (soda ash) by the Solvay
process. It is used in the manufacture of dry cell batteries,
explosives, dyes, used as a washing powder, as a soldering flux,
as a chemical reagent, and as a medicinal additive to livestock
feed. It is also used in pharmaceutical preparations and freezing
mixtures.
The industry profile for this subcategory is given in Table
32-1, while existing regulations are summarized in Table 32-2.
No priority pollutants were found at significant
concentrations in the waste during screening of Ammonium Chloride
Plant #736. Ammonium was found to be the only pollutant of
significance. Since ammonia is not a priority pollutant, this
subcategory has been recommended as an exclusion candidate under
Paragraph 8.
620
-------
TABLE 32-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
AMMONIUM CHLORIDE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
6
3
52,400 kkg/year
29,800 kkg/year
4,600 kkg/year
13,400 kkg/year
17 years
43 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
621
-------
TABLE 32-2 - EXISTING REGULATIONS .- EFFLUENT .LIMITATION GUIDELINES
SIH^TEGORY Ammonium Chloride
SUBPAKT X (40CFR 415.240, 5/22/75)
STANDARDS
Product Para-
Process meters
Mronium
Chloride NH3~N
(Anhydrous)
S01^ NH.-N
By-Product ^3
BPCTCA
Max. Avg.
kg/kkg k/kkg
(mg/1) (mg/1)
No discharge
of pwwp3
8.8 4.4
BATEA
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
No discharge
of pwwp
NSPS
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
No discharge
of pwwp
= Maximum of any one day.
"i
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants.
622
-------
SECTION 33
AMMONIUM HYDROXIDE INDUSTRY
33.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
33.1.1 Industry Profile and Analytical Results
Ammonium hydroxide is predominately used as a chemical
intermediary and reagent. It is also used in the dyeing and
bleaching of fabrics, the production of ammonium salts and
aniline dyes, and the extraction of alkaloids from plants.
The industry profile for this subcategory is given in Table
33-1, while existing regulations are summarized in Table 33-2.
No plants in this subcategory were found that had a
discharge. Therefore, this industry has been recommended as a
Paragraph 8 exclusion candidate.
623
-------
TABLE 33-1
SIJECATEGORY PROFILE DATA .SUMMARY
SUBCAIEGORY
AMMONIUM HYDROXIDE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
41,800 kkg/year
17,000 kkg/year
206 kkg/year
9,500 kkg/year
10 years
26 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
624
-------
TABLE 33-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SUBCATEGOKY
SUBPART
Ammonium Hydroxide
Y (40CFR 415.250, 5/22/75)
STANDARDS
Product
Process
Para-
meters
BPCTCA
1 2
Max. Avg.
kg/kkg k/kkg
(mg/1) (mg/1)
BATEA
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
NSPS
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
Amonium
Hydroxide
Reserved
Reserved
Reserved
Reserved
"Max, = Maximum of any one day.
Avg. = Average of daily values for thirty consecutive days shall not exceed.
625
-------
SECTION 34
BARIUM CARBONATE INDUSTRY
34.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
34.1.1 Industry Profile and Analytical Results
Barium carbonate is used in glass manufacturing, as a flux
in ceramics and enamelling, as an intermediate in the production
of barium oxide and hydroxide and as a coating for photographic
paper. It is also used in the synthetic dyestuff industry and
for the removal of soluble sulfate in brick manufacturing.
The industry profile for this subcategory is given in Table
34-1, while existing regulations are summarized in Table 34-2.
No priority pollutants were found at significant levels in
the waste during screening of Barium Carbonate Plant #360. On
the basis of these findings, this subcategory has been
recommended as an exclusion candidate under Paragraph 8.
626
-------
TABLE 34-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
BARIUM CARBONATE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
7
5
57,000 kkg/year
48,745 kkg/year
158 kkg/year
26,190 kkg/year
9 years
24 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
627
-------
TABLE 34-2 - EXISTING REGULATIONS - EFFLUENT LIMITfiTICN GUIDELINES
SUBCATEGORY
SUBPART
Barium Carbonate
Z (40CFR 415.260, 5/22/75)
STANDARDS
Product
Process
Barium
Carbonate
Para-
meters
Reserved
BPCICA
1 2
Max. Avg.
kg/kkg k/kkg
(mg/1) (mg/D
Reserved
BA1EA
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
Reserved
NSPS
Max.
k/kkg
(mg/D
Reserved
Avg.
k/kkg
(mg/1)
= Maximum of any one day,
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
628
-------
SECTION 35
BORIC ACID INDUSTRY
35.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
35.1.1 Industry Profile and Analytical Results
Boric acid is used in the manufacture of chromic oxide,
glazes, enamels, textile fiberglass, and heat resistant glass.
It is also used medicinally as a mild antiseptic and in atomic
power plants as a nuclear moderator.
The industry profile for this subcategory is given in Table
35-1 and the existing regulations are summarized in Table 35-2.
Priority pollutants
during- screening of Boric
found at
Acid Plant
significant
#778 were:
concentrations
Pollutant
Concentration (ug/1)
Copper 340
Thallium 140
Zinc A 1190
Bis(2-ethy]^exyl)
phthalate' 530
Mercury 1.6
This subcategory has only three plants, and
water discharge is not high. Because of the
industry, it has been recommended that this
further studied under Phase II.
the total waste
nature of this
subcategory be
629
-------
TABLE 35-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
BORIC ACID
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
122,600 kkg/year
3
2
97,500 kkg/year
93,850 kkg/year
77 percent
30,156 kkg/year
63,694 kkg/year
30 years
83 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
630
-------
TABLE 35-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SUBCMEGORY
SUBPAKT
Boric Acid
AB (40CFR
415.280, 5/22/75)
STANDARDS
Product
Process
BPCTCA BATEA
Max. Avg. Max. Avg.
Para- kg/kkg k/kkg k/kkg k/kkg
rosters (mg/1) (mg/1) (mg/1) (mg/1)
NSPS
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
Boric
Acid AS
(Ore-mined)
(TRONA)
TSS
AS
TSS
0.0028 0.0014
0.14 0.07
No discharge
of pwwp 3
No discharge
of pwwp
No discharge
of pwwp
Max, =
Maximum of any one day.
T
Avg. = Average of daily values for thirty consecutive days shall not exceed.
pwwp = Process wastewater pollutants.
631
-------
SECTION 36
CALCIUM CARBONATE INDUSTRY
36.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
36.1.1 Industry Profile and Analytical Results
Calcium carbonate is manufactured both in pure and impure
form and it is extensively used in many industries. In the pure
form, it is used in the rubber, paint, cement, paper and
pharmaceutical industries.
The industry profile for this subcategory is given in Table
36-1, while existing regulations are summarized in Table 36-2.
No priority pollutants were found at significant levels in
the raw waste during screening of Calcium Carbonate Plant #883.
On the basis of these findings, this subcategory has been
recommended as an exclusion candidate under Paragraph 8.
632
-------
TABLE 36-1
SUBCATEGORY PROFILE DATA .SUMMARY
SUBCATEGORY
CALCIUM CAPBONATE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
129,600 kkg/year
81,300 kkg/year
72,400 kkg/year
56 percent
555 kkg/year
49,800 kkg/year
25 years
50 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
633
-------
TABLE 36-Z - EXISTING REGULATIONS - EFFHJENT LIMITATION GUIDELINES
SUBCATEGOKY
SUBPART
Calcium Carbonate
AD (40CFR 415.310, 5/22/75)
STANDARDS
Product
Process
Para-
meters
BPCTCA
1 2
Max. Avg.
kg/kkg k/kkg
(mg/1) (mg/1)
BATEA
Max. Avg.
k/kkg k/kkg
Cmg/1) (mg/1)
NSPS
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
Calcium
Carbonate
(Milk of
Lime)
Solvay
Recovery
TSS
TSS
0.56
(50.0)*
1.16
(49.6)
0.28
(25.0)
0.58
(24.8)
Max, = Maximum of any one day,
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
*flow basis 11,200 1/kkg.
634
-------
SECTION 37
CUPROUS OXIDE INDUSTRY
37.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
37.1.1 Industry Profile and Analytical Results
Copper oxide is used in the manufacture of glass, ceramics,
marine paints and photoelectric cells. It is also used in
agriculture as a seed fungicide, and as an antiseptic and
catalyst.
The industry profile for this subcategory is given in Table
37-1, while existing regulations are summarized in Table 37-2.
Only one plant was found to be producing this product at the
time of screening. Because this is now a single plant industry,
this subcategory has been recommended for exclusion under
Paragraph 8.
635
-------
TABLE 37-1 SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY CUPROUS OXIDE
Total subcategory capacity rate Unknown
Total subcategory production rate Unknown
Number of plants in this subcategory NO plants
308 Data on file for Unknown
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
636
-------
TABLE 37-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SOBCATEGORY Cuprous Oxide
SUBPART AK (40CFR 415.370, 5/22/75)
STANDARDS
PBCTCA BATEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (ng/1) (mg/1) (rog/D (mg/1) (mg/D
Reserved Reserved Reserved Reserved
wax, = Maximum of any one day.
Avg. = Average of daily values for thirty consecutive days shall not exceed.
637
-------
SECTION 38
MANGANESE SULFATE INDUSTRY
38.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
38.1.1 Industry Profile and Analytical Results
Manganese sulfate is normally sold as a mixture of tetra and
penta hydrates. It is used in oils for the manufacture of
varnishes, in dyeing and in the manufacture of porcelain. It is
also used in the fertilizer industry.
The industry profile for this subcategory is given in Table
38-1, while existing regulations are summarized in Table 38-2.
Only one plant in this subcategory was found to be i-n
production- at the time of screening. Out of the eight plants
contacted, four no longer produced it, two were fertilizer
manufacturers and one manufactured reagent grade manganese
sulfate. Because this is now a single plant industry, this
subcategory has been recommended for exclusion under Paragraph 8.
638
-------
TABT.K38-1 SUBCaTEGQRY PROFILE DATA .SUMMARY
SUBCATEGORY MANGANESE SULFATE
Total subcategory capacity rate Unknown
Total subcategory production rate Unknown
Number of plants in this subcategory No Plants
308 Data on file for Unknown
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
639
-------
TABLE 38-2 - EXISTING REGULATIONS - EFFLUENT LZMTTATICM
SUBCMEGORY Manganese Sulfate
SUBPART AT (40CFR 415.460, 5/22/75)
^~ STANDARDS
P3CTCA BATEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/D (mg/1) (mg/1) (mg/1)
Manganese Reserve^ Reserved Reserved Reserved
Sulrate
"wax, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
640
-------
SECTION 39
STRONG NITRIC ACID INDUSTRY
39.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
39.1.1 Industry Profile and Analytical Results
Strong or concentrated nitric acid is used in the
manufacture of organic compounds where nitric acid is required to
act as an oxidizing agent rather than as an acid. It is also
used in the manufacture of dye intermediates, and explosives.
The industry profile for this subcategory is given in Table
39-1, while existing regulations are summarized in Table 39-2.
Priority pollutants found in the waste streams during
sampling of Strong Nitric Acid Plants were:
Maximum
Pollutant Concentration Observed (ug/1)
Screening Verification
(2 Plants) (1 Plant)
Chromium
Zinc
Lead
Mercury
Silver
Nickel
Cadmium
Cyanide
40,000
900
70
8.
•
<5
<2
•
6
69
02
<50
115
<10
1.
<15
<50
<2
<.
2
02
In a followup, it was found that the chromium and zinc are
used as corrosion inhibitors in the cooling water, and are not
process related. The other values are below significant levels.
Verification sampling at Plant #623 confirmed this.
On the basis of these findings, this subcategory has been
recommended for exclusion under Paragraph 8.
641
-------
TABLE 39-1
SUECATEGORY PROFILE DATA SUMMARY
SUBCATEQORY
STRONG NITRIC ACID
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
155,200 kkg/year
121,000 kkg/year
5,300 kkg/year
60,200 kkg/year
11 years
49 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
642
-------
39-2 - EXISTING REGULATIONS - EFFLUENT .LIMITATION GUIDELINES
SUBC&TEGORY Strong Nitric Acid
SUBPAKT AV (40CFR 415.480, 5/22/75)
STANDARDS
BPCICA BATEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
Strong
Nitric Reserved Reserved Reserved Reserved
Acid
wax. = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
643
-------
SECTION 40
OXYGEN AND NITROGEN INDUSTRY
40.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
40.1.1 Industry Profile and Analytical Results
Oxygen, along with nitrogen, is produced from air by
distillation of liquefied air. Oxygen is used in the production
of steel, gas welding, medicine, jet fuel, sewage treatment
plants and in the manufacture of ethylene and acetylene. In
rocket propullsion, liquid oxygen is often used as a crygenic
liquid oxidizer in the main stage boosters used for space
exploration.
The largest use of nitrogen is in the manufacture of ammonia
by the Haber process. It is also used in cryosurgery. As an
inert gas, it is used to prevent oxidation by air. In the liquid
form, it is used for low temperature refrigeration.
The industry profile for this subcategory is given in Table
40-1, while existing regulations are summarized in Table 40-2.
Only one priority pollutant was found at a significant level
in the raw waste during screening of Oxyen and Nitrogen Plant
#993.
Pollutant Concentration (ug/1)
Copper 590
Due to the small quantity of waste water discharged by the
industry and the resulting low waste load generated, this
subcategory has been recommended as an exclusion candidate under
Paragraph 8.
644
-------
TABLE 40-1
SUBCATEGORY PROFILE DATA .SUMMARY
SUBCATEGORY
OXYGEN AND NITROGEN
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
31,174,000 kkg/year
171
9
1,588,000 kkg/year
1,473,000 kkg/year
5 percent
2,400 kkg/year
378,000 kkg/year
4 years
36 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
645
-------
TABLE 40-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SOBCATEGOKY Oxygen and Nitrogen
SUBPAKT AW (40CFR 415.490, 5/22/75)
STANDARDS
Product
Process
BPCTCA
1 2
Max. Avg.
Para- kg/kkg k/kkg
meters (mg/1) (mg/1)
BATEA
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
NSPS
Max . Avg .
k/kkg k/kkg
(mg/1) (mg/1)
Oil and 0.002 0.001
(51'3)* (25'6)
"Max, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
*flow basis 39 1/kkg.
646
-------
SECTION 41
POTASSIUM IODIDE INDUSTRY
41.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
41.1.1 Industry Profile and Analytical Results
Potassium iodide is used in photographic emulsions, in
animal and poultry feeds, table salts and analytical chemistry.
It also has a number of medical uses.
The industry profile for this subcategory is given in Table
41-1, while existing regulations are summarized in Table 41-2.
Priority pollutants found during screening of Potassium
Iodide Plant #118 were:
Pollutant Concentration (ug/1)
Copper 1900
Thallium 28
Zinc 930*
Silver 35
*The water supply was found to have 900 ug/1 zinc and is presumed
to be the source.
Due to the small quantity of waste water discharged by the
industry, and resulting low waste loads generated, this
subcategory has been recommended as an exclusion candidate under
Paragraph 8.
647
-------
TABLE 41-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
POTASSIUM IODIDE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
122,560 kkg/year
9
4
1,985 kkg/year
1,300 kkg/year
10 percent
79 kkg/year
634 kkg/year
27 years
42 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
648
-------
TABLE 41-2 -
EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SUBCATEGORY
SUBPART
Potassium Iodide
AY (40CFR 415.510, 5/22/75)
STANDARDS
Product Para-
Process meters
Potassium Tgs
Iodide
Sulfide
Iron
Barium
BPCTCA BATEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
(mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
0.09
(75.0)*
0.015
(12.5)
0.015
(12.5)
0.009
(7.5)
0.03
(25.0)
0.005
(4.2)
0.005
(4.2)
0.003
(2.5)
Max, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
*flow basis 1200 1/kkg.
649
-------
SECTION 42
SODIUM HYDROSULFIDE INDUSTRY
42.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
42.1.1 Industry Profile and Analytical Results
Sodium hydrosulfide is used in the manufacture of sodium
sulfide and other chemicals and paper (Kraft) . It is also used
in dehairing of hides and industrial waste water treatment.
The industry profile for this subcategory is given in Table
42-1, while existing regulations are summarized in Table 42-2.
Priority pollutants found in the waste during screening of
Sodium Hydrosulfide Plant £144 were:
Pollutant Concentration (ug/1)
Phenol 76
Napthalene 90
Due to the very small flows and waste loads generated by
this industry, this subcategroy has been recommended as a
Paragraph 8 exclusion candidate.
650
-------
TABLE 42-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
SODIUM HYDROSULFIDE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
12
3
56,900 kkg/year
44,700 kkg/year
3,800 kkg/year
36,500 kkg/year
5 years
14 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
651
-------
TABLE 42-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SUBCAIEGORY Sodium Hydrosulf ide
SUBPART BD (40CFR 415.560, 5/22/75)
STANDARDS
BBCTCA BATEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
Sodium
Hydro- Reserved Reserved Reserved Reserved
Sulfide
Max, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
652
-------
SECTION 43
SODIUM SILICOFLUORIDE INDUSTRY
43.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
43.1.1 Industrial Profile and Analytical Results
Sodium Silicofluoride is used in the manufacture of sodium
fluoride and in the light metal industry as a protective agent.
It is also used as an insecticide, as a fluxing and opaquing
agent for ceramics and in detergent products.
The industry profile for this subcategory is given in Table
43-1, while existing regulations are summarization in Table 43-2.
This subcategory was not included in the present study.
Screening has been recommended under Phase II.
653
-------
43-1 SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY SODIUM SILICOFLUORIDE
Total subcategory capacity rate
Total subcategory production rate 51,800 kkg/year
Number of plants in this subcategory 6
308 Data on file for 1
With total capacity of 7,460 kkg/year
With total production of 3,970 kkg/year
Representing capacity
Representing production 7.5 percent
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
654
-------
TABLE 43-2 ~ EXISTING REGULATIONS ~ EFFLUENT LIMITATION GUIDELINES
SUBCATEGORY Sodium Silicofluoride
SUBPART BF (40CFR 415.580, 5/22/75)
"" STANDARDS
BPCTCA* BATEA* NSPS*
Max. Avg, Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
Sodium 0 - 0 25
& Fluorlae <«•<»*• «»•«
mcc 0-6 0.3
(48.0) (24.0)
Sections 415.580, 415.581, and 415.582 were revoked by the Agency and are
presently reserved (41 FR 51601, November 23, 1976) .
"wax, = Maximum of any one day,
o
Avg. = Average of daily values for thirty consecutive days shall not exceed.
**flow basis 12,500 1/kkg.
655
-------
SECTION 44
SODIUM THIOSULFATE INDUSTRY
44.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
44.1.1 Industry Profile and Analytical Results
Sodium thiosulfate is extensively used in the development of
negatives and prints in the photographic industry. It is also
used in medicine, in the paper and dyeing industries and as a
bleaching agent for natural products.
The industry profile data are given in Table 44-1, while
existing regulations are summarized in Table 44-2.
No priority pollutants were found at significant levels in
the raw waste during screening of Sodium Thiosulfate Plant #987.
On the basis of these findings, this subcategory has been
recommended as an exclusion candidate under Paragraph 8.
656
-------
TABLE 44-.1
SUBCATEGORY PROFILE DATA .SUMMARY
SUBGATEGORY
SODIUM THIOSULFATE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum.
Maximum
Volume per unit product:
Minimum
Maximum
6
5
88,000 kkg/year
70,300 kkg/year
4,400 kkg/year
27,000 kkg/year
3 years
51 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chenical Industry."
657
-------
TABLE 44-Z - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SUBCATEGORY
SUBPART
Sodium Thiosulfate
BG (40CFR 415.590, 5/22/75)
STANDARDS
Product
Process
Para-
meters
BPCTCA
Max. Avg.
kg/kkg k/kkg
(mg/1) (mg/1)
BATEA
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
NSPS
Max. Avg.
k/kkg k/kkg
(mg/1) (mg/1)
Sodium
Thio-
sulfate
Reserved
Reserved
Reserved
Reserved
"Max, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
658
-------
SECTION 45
SULFUR DIOXIDE INDUSTRY
45.1 ASSESSMENT OF THE WATER POLLUTION POTENTIAL
45.1.1 Industry Profile and Analytical Results
Most sulfur dioxide is produced in the gaseous form,
although a small percentage is also produced in liquid form. In
the gaseous form, it is predominantely used in on-site
manufacture of sulfuric acid. It is also used in the paper and
petroleum industries, as well as for fermentation control in the
wine industry, for bleaching in the textile and food industries
and in the production of other chemicals.
The industry profile data in this subcategory are given in
Table 45-1, while existing regulations are summarized in Table
45-2.
No priority pollutants were found at significant levels in
the waste during screening of Sulfur Dioxide Plant #363. On the
basis of these findings, this subcategory has been recommended as
an exclusion candidate under Paragraph 8.
659
-------
TABLE 45-1
SUBCATEGORY PROFILE DATA SUMMARY
SUBCATEGORY
SULFUR DIOXIDE
Total subcategory capacity rate
Total subcategory production rate
Number of plants in this subcategory
308 Data on file for
With total capacity of
With total production of
Representing capacity
Representing production
Plant production range:
Minimum
Maximum
Average production
Median production
Average capacity utilization
Plant age range:
Minimum
Maximum
Wastewater flow range:
Minimum
Maximum
Volume per unit product:
Minimum
Maximum
15
5
453,000 kkg/year
364,000 kkg/year
27,800 kkg/year
170,000 kkg/year
3 years
51 years
Sources of data are Stanford Research Institute, Directory of Chemical
Producers, U.S.A., 1977, U.S. Department of Commerce, Current Industrial
Reports, December 1977; Energy and Environmental Analysis, Inc.; Draft
Report, "Preliminary Economic Assessment of Effluent Limitations in the
Inorganic Chemical Industry."
660
-------
45-2 - EXISTING REGULATIONS - EFFLUENT LIMITATION GUIDELINES
SUBCATEGORY Sulfur Dioxide
SUBPART BI (40CFR 415.610, 5/22/75)
^ STANDARDS
BPCTCA BAIEA NSPS
1 2
Max. Avg. Max. Avg. Max. Avg.
Product Para- kg/kkg k/kkg k/kkg k/kkg k/kkg k/kkg
Process meters (mg/1) (mg/1) (mg/1) (mg/D (mg/D (mg/D
D'oxide Reserved Reserved Reserved Reserved
Max, = Maximum of any one day.
2
Avg. = Average of daily values for thirty consecutive days shall not exceed.
661
-------
REFERENCES
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TM
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662
-------
REFERENCES (continued!
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663
-------
REFERENCES (.continued)
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664
-------
REFERENCES (.continued}
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665
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REFERENCES (.continued)
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666
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Processes and Monitoring. EPA-902/9-74-001. U.S. Environ-
mental Protection Agency, 1973. 342 pp.
669
-------
BIBLIOGRAPHY - continued
Shen, Y.S. Study of Arsenic Removal from Drinking Water. Water
Journal American Water Works Association 65 (8):543-548, 1973.
Sigworth, E. A., and S. B. Smith. Adsorption of Inorganic
Compounds by Activated Carbon. Journal American Water Works
Association 64 (6) : 386-390, 1972.
Smith, R. Cost of Conventional and Advanced Treatment of Waste-
water. Journal Water Pollution Control Federation 40(9):
1546-1574, 1968.
Sonksen, M. K., F. M. Sittig, E. F. Maziarz. Treatment of Oily
Wastes by Ultrafiltration/Reverse Osmosis. A Case History.
The 33rd Annual Industrial Waste Conference, West Lafayette,
Indiana, 1978. 28 pp.
Stanford Research Institute. Directory of Chemical Producers
U.S.A. 1977.
Stinson, G. F. Electrochemical Wastewater Treatment Process.
Personal Communication. 1978.
Thiem, L. D. Badorek, and J. T. O'Connor. Removal of Mercury
From Drinking Water Using Activated Carbon. Journal
American Water Works Association 68 (8) :447-451, 1976.
Thompson, G.S. Jr. First Annual Conference on Advanced Pollution
Control for the Metal Finishing Industry. EPA-600/8-78-010.
U.S. Environmental Protection Agency, 1978. 143 pp.
S. K. Williams Company. Waste Water Treatment and Reuse in
a Metal Finishing Job Shop. EPA-670/2-74-042. U.S. Environ-
mental Protection Agency, 1974. 67 pp.
Wiseman, S., and B. T. Bawden. Removing Refractory Compounds
From Waste Water. Chemical Engineering Progress 73(5):60-64,
1977.
Zabban, W., and R. Helwick. Defluoridation of Wastewater. The
30th Annual Industrial Waste Conference, West Lafayette,
Indiana, 1975. 38 pp.
Zievers, J. F., R. E. Wing, S. Grain, and D. Gordon. Practical
Use of Starch Insoluble Xanthates. Industrial Filter and
Pump MFG. Co. 1977. 20 pp.
670
-------
ACKNOWLEDGEMENTS
The staff of Jacobs Environmental Division of Jacobs
Engineering Group Inc. is gratefully acknowledged for their
assistance in field investigations, sample analysis, technical
engineering, and preparation of the report. Mr. Henry Cruse was
Program Director at Jacobs, the Project Manager was Mr. Michael
Warner, and the Jacobs personnel who provided major technical
input to this project were:
Bonnie J. Parrott
Mazhar Mohiuddin
Mahendra L. Shah
Carl B. Johnston
Dr. Kar Y. Yu
W. Dennis Merklin
Mark K. Jackson
John H. Taylor, Jr.
(Laboratory Director)
Dr. Nelson F. Phelan
(Senior Analytical Chemist)
Dale R. Rushneck
(Mass Spectroscopist)
Acknowledgement and appreciation are also extended to Dr.
Martin D. Schwartz and Dr. Ben C. Edmondson of Technology
Associates of Southern California, Inc. for their invaluable
contributions to the project.
The assistance of the EPA project officers and staff of the
Effluent Guidelines Division is also greatly appreciated,
including the guidance given by Mr. Walter J. Hunt who was the
Inorganic Chemicals Branch Chief through January, 1979.
671
-------
APPENDIX A
ANALYSIS OF LONG TERM EFFLUENT
MONITORING DATA
FOR
THE INORGANIC CHEMICALS INDUSTRY
INTRODUCTION
This appendix contains tabulated summaries of the
statisical parameters derived from the analysis of long term
effluent monitoring data colleced by industry and reported to
the EPA or state regulatory agencies during the last two or
three years. The particular sets of data selected for
analysis are taken from plants which apply a well defined
treatment technology to process waste waters from single
product or product group manufacturing operations associated
with a specific subcategory. Data have been excluded which
represent waste waters diluted with noncontact cooling water
or commingled with waste sources from unrelated products.
Each table in the appendix indicates the actual number of
observations on which the calculated statistical parameters
are based. The derivation of the parameters was discussed in
Section 9 of the draft report.
The statistical performance information presented here
was used to develop the control parameter limitations for
each subcategory considered in detail in the main report.
These were expressed as the achievable Quality Limits (mg/1)
and Emission Limits (kg/kkg) for each pollutant assuming the
model plant flow conditions and applying the specified
pollutant removal technologies at each level of treatment.
The tables on the following pages summarize the available
historical effluent monitoring results and give the
individual plant performance characteristics in concentration
and loading units for both daily and monthly measurements.
Three sets of variability factors are shown on each table
however, only the middle value (Variability Factor II) is
used to calculate the plant "Performance Standards" shown in
the right hand column of each table. Similarly, the
Variability Factor Ratio (VFR) used to calculate the
subcategory "Control Parameter Limitations" is the
Variability Factor II for daily measurements divided by
Variability Factor II for 30-day average data.
In general, the monitoring time period for most firms
doing so for NPDES permits was from January 1, 1975 through
June 30, 1976. Firms who monitored over this time period
provided up to 18 months of 30 day average data and as many
A-l
-------
as 547 measurements of daily or 24 hour data. In cases where
monitoring was done less frequently than daily, perhaps
omitted on weekends, or only weekly measurements, the actual
number of observations used in the calculation is recorded
for each parameter.
Included in this Appendix are statistical measures
appropriate to the analysis of long term monitoring data and
the historical performance of inorganic chemical pollutant
discharge levels. The statistics presented include measures
of amount or level of pollutant discharge, such as long term
average, minimum level, and maximum level for both daily, or
24 hour measurements, as well as 30 day average measurements.
Also given in the table is the co-efficient of
variation, CV, which relfects the dispersion of measurements
above and below the long term average level. Other measures
of variability that may be of interest, such as range or
standard deviation are also calculated for any parameter from
any information given herein. In addition to statistics of
pollutant level and variation of pollutant level, three
variability factors are printed in each parameter. A
variability factor is the ratio of an upper percentile of the
distribution of pollutant measurements to the long term
average pollutant level. The basis of the particular upper
percentile chosen for Variability Factors I, II, and III is
explained as a footnote to the table.
The historical performance of each firm, using
Variability Factor II, is given for each parameter and is
expressed in the same units as the long term average.
For reference, the tables in this Appendix are organized
by inorganic chemical subcategory and the manufacturing
process in that subcategory. For each plant, as many as four
tables are included. These tables appear in the following
order :
1. Daily measurements of pollutant concentrations in the
effluent stream given in parts per million (ppm).
2. Daily measurements of total effluent discharge load
measured in kilograms per day.
3. 30 Day averages of pollutant concentration (ppm).
4. 30 Day averages of total effluent pollutant load
(kg/day) .
A-2
-------
Table A-la
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Chlorine
Mercury Cell Process
Plant #747
Parameter
(ppn)
Historical Summary
Statistics
Variability Performance
Factors Standards
No Min Aver Max CV
II III (V.F. II)
Mercury,Hg 530 .006 .014 .021 .286 1.54 1.88 2.15
TSS 530 1.00 7.4 62. .581 2.09 3.04 3.87
Chlorine,C12 428 0.08 .638 1.50 .463 1.75 2.28 2.71
(Total Residual)
.026
22.5
1.46
I -
II -
III -
95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-3
-------
Table A-lb
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Chlorine
Mercury Cell Process
Plant #747
Parameter
(kg/day)
Historical Summary
Statistics
Variability Performance
Factors Standards
No Min Aver Max CV
II III (V.F. II)
Mercury,Hg 530 .015 .031 .047 .129 1.24 1.66 1.84 .051
Chlorine,C12 420 .156 1.44 3.40 .463 1.87 2.54 3.09 3.65
(Available)
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-4
-------
Table A-lc
Historical Effluent Monitoring Data Summary
with Variability factors and Performance Standards
30 "Day Averages
Subcategory Chlorine
Mercury Cell Process
Plant #747
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppn) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 18 .008 .014 .020 .293 1.40 1.47 1.67 0.21
TSS 18 5.1 7.4 12.9 .355 1.49 1.58 1.83 11.7
Chlorine,C12 18 .380 .638 .847 .194 1.27 1.38 1.45 0.88
(Available)
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-5
-------
Table A-ld
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Chlorine
Mercury Cell Process
Plant #747
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 18 .020 .031 .037 .197 1.28 1.33 1.47 .041
Chlorine,C12 18 .91 1.44 2.23 1.35 1.50 1.59 2.16
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-C
-------
Table A-2a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Chlorine
Mercury Cell Process
Plant #317
Historical Summary
Statistics
Parameter
(ppb) No Min Aver Max CV I
Variability Performance
Factors Standards
II III (V.F. II)
Mercury,Hg 516 .041 .634 2.87 .910 2.62 4.52 6.40 2.87
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-7
-------
Table A-2b
Historical Effluent Monitoring Eata Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Chlorine
Mercury Cell Process
Plant #317
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 516 .0005 .011 .088 .818 2.58 4.35 6.10 .046
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-8
-------
Table A-2c
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Chlorine Subcategory
Mercury Cell Process
Plant #317
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppb) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 17 .325 .634 1.15 .293 1.42 1.45 1.68 0.919
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-9
-------
Table A-2d
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Chlorine
Mercury Cell Process
Plant #317
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 17 .005 .011 .019 .273 1.38 1.45 1.64 .015
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-10
-------
Table A-3a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Chlorine
Mercury Cell Process
Plant #195
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppm) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 349 .0005 .014 .136 2.29 3.69 9.45 17.49 0.132
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-ll
-------
Table A-3b
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Chlorine
Mercury Cell Process
Plant #195
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 349 .0001 .003 .088 2.33 3.77 10.22 19.60 .028
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-12
-------
Table A-3c
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Chlorine
Mercury Cell Process
Plant #195
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppn)
No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 17 .0009 .014 .062 1.21 2.67 2.99 3.82 .042
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-13
-------
Table A-3d
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Chlorine
Mercury Cell Process
Plant #195
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 17 .0002 .003 .014 1.33 2.88 3.22 4.15 .0088
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-14
-------
Table A-4a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Chlorine
Mercury Cell Process
Plant #324
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppn) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 82.002 .004 .011 .500 1.73 2.24 2.66 0.009
Chlorine,C12 49 2.0 19.1 62 1.01 2.78 4.96 7.23 94.7
(Total Residual)
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-15
-------
Table A-4b
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Chlorine
Mercury Cell Process
Plant #324
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 82 .021 .047 .118 .383 1.71 2.20 2.66 .104
Chlorine,C12 49 20.5 203 663 1.03 2.81 5.04 7.39 1026
(Residual)
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-16
-------
Table A-4c
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Chlorine
Mercury Cell Process
Plant #324
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppm) No Min Aver Max CV I II III (V.F. II)
Mercury,Hg 22 .003 .004 .008 .250 1.42 1.60 1.71 0.006
Chlorine,C12 14 4.0 19.1 57.8 .969 2.34 2.91 3.25 55.6
(Total Residual)
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-17
-------
Table A-4d
Historical Effluent Monitoring Eata Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Chlorine
Mercury Cell Process
Plant #324
Parameter
(kg/day)
Historical Summary
Statistics
Variability Performance
Factors Standards
No Min Aver Max CV
II III (V.F. II)
Mercury,Hg 22 .032 .047 .098 .340 1.47 1.66 1.78 .079
Chlorine,C12 14 39.1 203 616 .945 2.33 2.89 3.22 588
(Residual)
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-18
-------
Table A-5a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Chlorine
Diaphram Cell Process
Plant #967
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Lead,Pb 153 .045 1.42 5.40 .824 2.51 4.12 5.69 5.85
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-19
-------
Table A-5b
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Chlorine
Diaphram Cell Process
Plant #967
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Lead,Fb 12 .460 1.42 5.40 .824 1.50 1.58 1.83 2.25
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-20
-------
Table A-6a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurments
Subcategory Hydrofluoric Acid
Plant #722
Parameter
(ppn)
Historical Summary
Statistics
Variability Performance
Factors Standards
No Min Aver Max CV
II III (V.F. II)
Arsenic,As 50 .020 .035 .100 .314 1.56 1.92 2.20 0.067
Fluoride,F 129 .25 1.39 4.00 .589 2.11 3.08 3.94 4.28
Ammonia,NH3 50 .01 .104 .40 .865 2.58 4.32 6.05 0.449
Lead,Pb 49 .10 .142 1.20 1.58 3.35 7.26 12.02 1.03
Zinc.Zn 51 .04 .140 .47 .807 2.49 4.06 5.59 0.569
TSS 41 1 21.1 144 1.13 2.93 5.48 8.23 116
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-21
-------
Table A-6b
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Hydrofluoric Acid
Plant #722
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Arsenic,As 50 .052 .383 .598 .345 2.01 2.84 3.57 1.09
Fluoride,F 129 3.98 16.4 65.4 .701 2.31 3.57 4.75 58.6
Ammonia,NH3 50 .114 1.13 4.77 .982 2.75 4.85 7.02 5.48
Lead,Pb 49 .261 1.68 15.0 1.51 3.30 6.98 11.39 11.8
Zinc,Zn 51 .125 1.63 4.64 .920 2.66 4.58 6.52 7.46
TSS 41 14.2 263 1962 1.21 3.02 5.79 8.86 1525
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-22
-------
Table A-6c
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Hydrofluoric Acid
Plant #722
Historical Summary Variability Performance
Parameter Statistics • Factors Standards
(ppm) No Min Aver Max CV I II III (V.F. II)
Arsenic,As 5 .020 .035 .058 .371 1.51 1.73 1.86 0.061
Fluoride,F 5 .769 1.39 2.24 .371 1.52 1.74 1.87 2.42
Ammonia,NH3 6 .028 .104 .170 .548 1.76 2.08 2.27 0.216
Lead,Pb 6 .100 .142 .322 .577 1.80 2.15 2.35 0.305
Zinc,Zn 6 .076 .140 .225 .429 1.59 1.84 1.99 0.258
TSS 5 8.83 21.1 32.4 .483 1.67 1.95 2.12 41.2
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-23
-------
Table A-6d
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Hydrofluoric Acid
Plant #722
Parameter
Historical Summary
Statistics
Variabilty Performance
Factors Standards
(kg/day)
Arsenic, As
Fluor ide,Fl
Ammonia ,NH3
Lead,Pb
Zinc,Zn
TSS
No
5
5
6
6
6
5
Min
.215
8.09
.279
.990
.715
106
Aver
.383
16.4
1.13
1.68
1.63
263
Max
.598
28.5
2.15
3.86
2.94
433
CV
.345
.438
.639
.596
.531
.487
1
1
1
1
1
1
I
.48
.61
.89
.83
.74
.67
II
1.68
1.87
2.27
2.18
2.05
1.96
III
1.
2.
2.
2.
2.
2.
80
02
49
39
24
13
(V.F. II)
.644
30.6
2.56
3.67
3.34
516
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
U - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-24
-------
Table A-7a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Hydrofluoric Acid/
Plant #705
Parameter
(kg/day)
Historical Summary
Statistics
Variability Performance
Factors Standards
No Min Aver Max CV
II III (V.F. II)
Fluoride 15 4.54 16.7 27.2 .449 1.62 1.74 2.05 29.0
TSS 16 7.26 28.6 52.2 .441 1.61 1.72 2.02 49.2
I -
II -
III -
All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-25
-------
Table A-8b
Historical Efficient Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Titanium Dioxide
Chloride Process
Plant #172
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Man Aver Max CV I II III (V.F. II)
Chromium,Cr 394 .000 .013 .210 1.69 3.45 7.78 13.2 .097
Copper,Cu 394 .000 .027 .190 1.04 2.85 5.20 7.70 .139
Zinc,Zn 394 .000 .028 .108 .679 2.25 3.42 4.50 .097
TSS 394 0.40 8.34 176. 1.92 3.54 8.35 14.6 69.7
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-26
-------
Table A-8c
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Titanium Dioxide
Chloride Process
Plant #172
Parameter
(ppn)
Chromium, Cr
Copper ,Cu
Zinc,Zn
TSS
Historical Summary
Statistics
No
13
13
13
13
Min
.000
.000
.001
1.20
Aver
.004
.010
.012
3.14
Max
.013
.030
.026
8.60
CV
.750
.700
.500
.599
Variability
Factors
I
2.03
2.01
1.66
1.83
II
2.46
2.43
1.93
1.98
III
2.72
2.69
2.10
2.39
Performance
Standards
(V.F. II)
0.010
0.024
0.023
6.22
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-27
-------
Table A-8d
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Titanium Dioxide
Chloride Process
Plant #172
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Chromium,Cr 13 .002 .013 .043 .769 2.14 2.62 2.91 .033
Copper,Cu 13 .000 .027 .100 .852 2.22 2.74 3.04 .073
Zinc,Zn 13 .004 .028 .051 4.29 1.56 1.80 1.94 .051
TSS 13 2.60 8.34 24.0 .695 1.96 2.14 2.62 17.9
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-28
-------
Table A-9a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Titanium Dioxide
Sulfate Process
Plant #559
Parameter
(ppn)
Historical Summary
Statistics
Variability Performance
Factors Standards
No Min Aver Max CV
II III (V.F. II)
Cadmium,Cd
Chromium,Cr
Iron,Fe
(total)
Iron,Fe
(diss)
Lead, Pb
Nickel,Ni
Zinc,Zn
TSS
26 .001 .009 .020 .444 1.77 2.03 2.35 0.018
26 .010 .021 .070 .857 2.54 4.23 5.87 0.088
30 .40 3.25 19.1 1.42 3.24 6.74 10.9 21.9
153 .080 .279 4.98 2.01 3.59 8.64 15.32 2.41
26 .002 .017 .050 .765 2.35 3.67 4.91
26 .010 .029 .080 .690 2.29 3.52 4.66
26 .010 .027 .300 2.11 3.63 9.93 18.8
183 35.8 1.71 3.44 7.70 13.0
0.062
0.102
0.268
276.
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-29
-------
Table A-9b
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Titanium Dioxide
Sulfate Process
Plant #559
Historical Summary
Parameter Statistics
(kg/day) No Min Aver Max CV
Variability Performance
Factors Standards
II III (V.F. II)
Cadmium,Cd
Iron,Fe
(Total)
Iron,Fe
(Diss)
Lead, Pb
Nickel,Ni
Zinc,Zn
TSS
26 .004 .062 .119 .435 1.83 2.44 2.95 .151
30 29 214. 1299 1.44 3.24 6.74 10.9 1444
153 4.0 19.4 400. 2.37 3.70 9.56 17.74 186.
26 .008 .115 .297 .652 2.23 3.36 4.40 .385
26 .057 .191 .463 .675 2.26 3.45 4.55 .658
26 .049 .190 2.24 2.24 3.67 9.24 16.9 1.75
183 57. 2390 1.76 3.46 7.86 13.4 18784
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-30
-------
Table A-9c
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Titanium Dioxide
Sulfate Process
Plant #559
Parameter
(PPtn)
Cadmium, Cd
Chromium, Cr
Iron,Fe
(Total)
Iron,Fe
(Dissolves)
Lead , Pb
Nickel ,Ni
Zinc,Zn
TSS
Historical Summary Variability
Statistics Factors
No
6
6
1
5
6
6
6
6
Win Aver Max
.003 .009 .013
.010 .021 .035
3.25
.150 .279 .400
.003 .017 .028
.012 .029 .042
.010 .027 .068
1.57 35.8 74.8
CV I II III
.333 1.46 1.55 1.78
.429 1.59 1.70 2.00
.259 1.36 1.42 1.60
.330 1.46 1.54 1.77
.529 1.68 1.80 2.14
.346 1.49 1.57 1.82
.741 2.05 2.23 2.75
.866 2.20 2.42 3.01
Performance
Standards
(V.F. II)
0.014
0.036
4.62
.430
0.031
0.045
0.060
86.6
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-31
-------
Table A-9d
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Titanium Dioxide
Sulfate Process
Plant #559
Parameter
(kg/day)
Cadmium, Cd
Chromium, Cr
Iron,Fe
(diss)
Lead,Pb
Nickel ,Ni
Zinc,Zn
TSS
Historical Summary
Statistics
No Min
6 .016
6 .070
5 10.0
6 .021
6 .080
6 .074
6 116.
Aver
.062
.136
19.4
.115
.191
.190
2390
Max
.085
.202
27.0
.160
.258
.498
4797
CV
.355
.338
.291
.417
.330
.774
.857
Variability
Factors
I
1.49
1.47
1.40
1.59
1.46
2.08
2.19
1.
1.
1.
1.
1.
2.
2.
II
58
56
46
69
54
27
41
III
1.83
1.79
1.68
1.98
1.77
2.81
3.00
Performance
Standards
(V.F. II)
.098
.212
28.4
.194
.294
..431
5759
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-32
-------
Table A-lOa
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Aluminum Fluoride
Plant #251
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppm) No Man Aver Max CV I II III (V.F. II)
Lead,Pb 152 0.11 2.28 12.8 .601 2.13 3.12 4.01 7.11
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-33
-------
Table A-lOb
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Aluminum Fluoride
Plant #251
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Lead,Pb
152 0.09 2.15 15.3 .753 2.40 3.82 5.17 8.20
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-34
-------
Table A-lOc
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Aluminum Floride
Plant 1251
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppn) No Min Aver Max CV I II III (V.F. II)
Lead,Pb 10 1.51 2.28 3.90 .601 1.47 1.55 1.78 3.54
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-35
-------
Table A-lOd
Historical Effluent Monitoring Eata Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Aluminum FLoride
Plant #251
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Lead,Pb 10 1.51 2.15 3.70 .326 1.45 1.54 1.76 3.30
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-36
-------
Table A-lla
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Chrome Pigments Subcategory
Plant #894
Parameter
(Ppn)
Arsenic ,As
Cadmium, Gd
Chromium, Cr
(hexavalent)
Chromium,Cr
Copper ,Cu
Lead,Pb
Mercury,Hg
Zinc,Zn
Cyanide, CN
(A)
Cyanide, CN
(total)
Historical Summary
Statistics
No
23
23
23
23
23
23
23
23
23
23
Variability
Factors
Min Aver Max CV I
.0096
.050
.028
.197
.038
.217
.0004
.012
.0003
.025
.079
.079
.112
.442
.134
.412
.001
.04
.019
.118
.235
.164
.592
.799
.296
1.635
.0018
.087
.076
.316
.622
.339
1.04
.404
.529
.681
.401
.437
1.57
.995
II
2.
1.
2.
1.
1.
2.
1.
1.
3.
2.
Ill
02
56
70
66
87
12
66
72
58
63
Performance
Standards
(V.F. II)
.156
.123
.302
.733
.250
.873
.0016
.074
.068
.310
SS 23 0.27 11.2 33.3 .662 2.01 22.5
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-37
-------
Table A-12a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Hydrogen Cyanide
Andrussow Process
Plant #782
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppm) No Min Aver Max CV I II III (V.F. II)
Ammonia,NH3 35 14. 113. 188. .335 1.62 2.02 2.34 229
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
expected to be within the performance standard, P.
(Z = 1.39)
A-38
-------
Table A-12b
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Hydrogen Cyanide
Andrussow Process
Plant #782
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Ammonia,NH3 35 112 1533 2419 .365 1.68 2.14 2.51 3283
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
expected to be within the performance standard, P.
(Z = 1.39)
A-39
-------
Table A-12c
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Hydrogen Cyanide
Andrussow Process
Plant #782
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppm) No Min Aver Max CV I II III (V.F. II)
Ammonia,NH3 8 80. 113. 134. .335 1.23 1.32 1.38 150
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-40
-------
Table A-12d
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Hydrogen Cyanide
Andrussow Process
Plant #782
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Ammonia,NH3 8 908 1533 1941 .212 1.29 1.42 1.49 2177
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-41
-------
Table A-13a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory
Andrussow Process
Plant #765
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppm) No Min Aver Max CV I II III (V.F. II)
Cyanide,CN 534 .01 .202 3.27 1.58 3.35 7.26 12.01 1.46
(Available)
Cyanide,CN 25 .039 .192 .460 .667 2.25 3.42 4.50 .065
(Total)
Ammonia,NH3 26 .193 3.63 10.2 .636 2.29 3.51 4.64 12.7
COD 25 2.71 15.9 45.2 .552 2.04 2.90 3.66 46.1
TOC 26 .783 8.30 25.6 .845 2.55 4.22 5.88 35.0
SS 22 5 35 267 1.57 3.34 8.16 11.9 286
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-42
-------
Table A-13b
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Hydrogen Cyanide
Andrussow Process
Plant #765
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppm) No Win Aver Max CV I II III (V.F. II)
Cyanide,CN 19 .082 .202 .351 .391 1.54 1.78 1.91 0.359
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-43
-------
Table A-13c
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Hydrogen Cyanide Subcategory
Andrussow Process
Plant #765
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Cyanide,CN 19 .082 .202 .351 .391 1.54 1.78 1.91 .358
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-44
-------
Table A-14a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Sodium Dichromate
Plant #493
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppn) No Min Aver Max CV I II III (V.F. II)
Chromiun,Cr 29 11 25 51 .314 1.58 1.95 2.24 48.7
(Total)
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-45
-------
Table A-14b
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Sodium Dichromate
Plant #493
Parameter
Historical Summary
Statistics
Variability Performance
Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Chromium,Cr 20 .005 .046 .342 1.80 3.47 7.92 13.56 .368
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-46
-------
Table A-15a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Nickel Sulfate
Plant #120
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppn)
No Min Aver Max CV I II III (V.F. II)
NickelfNi 88 .080 1.83 8.33 1.21 3.03 5.84 8.96 10.7
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-47
-------
Table A-15b
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
Daily Measurements
Subcategory Nickel Sulfate
Plant #120
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Nickel,Ni 88 1.02 8.32 44.6 1.31 3.13 6.24 9.80 51.9
I - 95% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 1.64)
II - 99% of the daily maximum measurements expected to be less
than the performance standard, P.
(Z = 2.33)
III - All but one daily maximum measurement per year expected
to be less than the performance standard, P.
(Z = 2.78)
A-48
-------
Table A-15c
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Nickel Sulfate
Plant #120
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(ppn)
No Min Aver Max CV I II III (V.F. II)
Nickel,Ni
3 1.29 1.83 2.48 1.21 1.38 1.54 1.63 2.82
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-49
-------
Table A-15d
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Nickel Sulfate
Plant #120
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day) No Min Aver Max CV I II III (V.F. II)
Nickel,Ni 3 5.04 8.32 11.1 .302 1.42 1.49 1.70 12.4
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-50
-------
Table A-16a
Historical Effluent Monitoring Data Summary
with Variability Factors and Performance Standards
30 Day Averages
Subcategory Sodium Hydrosulfite
Plant #672
Historical Summary Variability Performance
Parameter Statistics Factors Standards
(kg/day)
No Min Aver Max CV
II III (V.F. II)
TSS
36 .91 3.78 41.1 1.69 3.35 3.77 4.94 14.2
I - All but one of the 12 monthly averages in one year are
expected to be within the performance standard, P.
(Z = 1.39)
II - 95% of the monthly averages are expected to be within the
performance standard, P.
(Z = 1.64)
III - 99% of the monthly averages are expected to be within the
performance standard, P.
(Z = 2.33)
A-51
------- |