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Final Report: Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
EPA Grant Number: R826694C635Subproject: this is subproject number 635 , established and managed by the Center Director under grant R828598
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Gulf Coast HSRC (Lamar)
Center Director: Ho, Tho C.
Title: Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
Investigators: Schlautman, Mark , Carraway, Elizabeth , Herbert, Bruce
Institution: Clemson University , Texas A & M University
EPA Project Officer: Krishnan, Bala S.
Project Period: September 1, 2000 through August 31, 2004
RFA: Gulf Coast Hazardous Substance Research Center (Lamar University) (1996)
Research Category: Hazardous Waste/Remediation , Targeted Research
Description:
Objective:The widespread occurrence of hydrophobic organic contaminants (HOCs) in soils, sediments, and aquifers has led to intensive studies of the mobility and fate of these compounds in subsurface environments. Because of their low solubilities and slow dissolution/desorption rates, many HOCs are associated with the solid phase or exist as nonaqueous phase liquids (NAPLs). Depending on the particular site conditions, two complementary remediation alternatives are often considered: (1) HOC sorption to an immobile phase that subsequently decreases HOC mobility, or (2) HOC partitioning to a mobile phase that results in an increase in HOC mobility (and apparent solubility) in water. For the first approach, use of organoclays or organooxides to remove HOCs from water has received much attention. For the second alternative, in-situ surfactant-enhanced aquifer remediation (SEAR) has been suggested as an economically and technically feasible remediation approach. To date, most field-scale SEAR applications have focused on the removal of NAPLs from contaminated aquifers by utilizing NAPL mobilization (i.e., brought about by lowering the NAPL-water interfacial tension) as well as enhanced solubilization of NAPL components in surfactant micelles. In contrast to NAPLs, however, we are aware of only one field-scale SEAR application that has been used to remove HOCs existing in a sorbed state for the purpose of aquifer restoration or risk mitigation. Enhanced HOC solubility in surfactant systems generally has been quantified by a distribution coefficient that only considers HOC partitioning to surfactant micelles that exist above the critical micelle concentration (cmc). Although surfactants can form a mobile micellar pseudophase that leads to the facilitated transport of solubilized HOCs, they also can be adsorbed by the solid matrix and thereby lead to HOC partitioning to immobile sorbed surfactants and, thus, enhanced HOC retardation. Therefore, the effectiveness of a remediation scheme utilizing surfactants depends on the distribution of an HOC between immobile compartments (e.g., subsurface solids, sorbed surfactants) and mobile compartments (e.g., water, micelles).Although the partitioning of HOCs to surfactant micelles has been well studied, HOC partitioning to sorbed surfactants (e.g., hemimicelles, admicelles) has received much less attention. Many previous studies of HOC partitioning to sorbed surfactants examined conditions favorable for the formation of surfactant bilayers resulting from high adsorption densities; in these studies, a single partition coefficient was often observed. However, for many expected surfactant remediation applications, a surfactant solution would likely be pumped into or near the contaminated subsurface environment, and thus aqueous surfactant concentrations would vary spatially and temporally from zero to the applied concentration. Also, because soil-surfactant and surfactant-surfactant interactions lead to highly nonlinear sorption isotherms, the transport of surfactant monomers and micelles would exhibit very complex behavior. Correspondingly, the HOC distribution between immobile and mobile phases would also be expected to show complex behavior depending on the surfactant mass in each phase. Finally, it is likely that the varying soil solution chemistries found in different subsurface environments will affect surfactant sorption to solid phases and subsequent HOC partitioning to micelles and sorbed surfactants. Therefore, a quantitative evaluation of any potential surfactant remediation approach must consider the distribution of surfactant and subsequent HOC partitioning to each phase as a function of solution chemistry to maximize efficiency and minimize remediation costs. Additional complications arise when DNAPLs and other HOCs contaminate fine-grain subsurface environments because of the low permeabilities of these systems. A promising remediation alternative for these types of contaminated systems is to combine surfactant-enhanced contaminant mobilization/solubilization with the accelerated transport obtained from electrokinetic (EK) processes. This integrated process will accelerate the flow of water in low-permeability soils and will exhibit a faster rate of cleanup due to enhanced mobilization and/or solubilization. Before this type of remediation can be utilized in field-scale operations, however, a thorough understanding of the various processes must be developed to prevent a failure of the technology. No systematic study, however, has examined these complex interactions, particularly in heterogeneous subsurface systems. Consequently, any analyses of its remediation performance must be based on fundamental investigations for the simultaneous application of surfactant addition and EK operation.The objective of this project was to develop a novel and effective remediation alternative for low-permeability subsurface environments contaminated with HOCs. The approach combined surfactant-enhanced contaminant solubilization/mobilization with the accelerated transport obtained from EK processes. The integration of these two processes should lead to faster rates of remediation than would be possible with either individual approach.
Summary/Accomplishments (Outputs/Outcomes):Partitioning of two HOCs, phenanthrene and naphthalene, to surfactant micelles, kaolinite and sorbed surfactants was studied to provide further insight on (1) the effectiveness of using sorbed surfactants to remove HOCs from water and (2) the feasibility of using surfactant-enhanced aquifer remediation (SEAR) for contaminated subsurface systems. Sorbed surfactant partition coefficients (Kss) showed a strong dependence on the surfactant sorption isotherms. At low sorbed surfactant levels Kss values were at their highest and then decreased with increasing surfactant sorption densities. Kss values for sodium dodecyl sulfate (SDS) were always larger than the corresponding micellar partition coefficient (Kmic) values. For Tween 80, however, Kss values were higher than Kmic values only at the lower sorbed surfactant concentrations. HOC distributions between the immobile and mobile phases varied with surfactant dose because of the competition between sorbed and micellar surfactants for HOC partitioning: distribution coefficients increased initially with increasing surfactant concentrations before decreasing at higher doses. Overall results demonstrated that surfactant sorption to the solid phase can lead to increases in HOC retardation when equilibrium conditions are applicable (e.g., slow advection rates), a desirable effect when the treatment objective is to immobilize HOCs by removing them from water but an undesirable effect in SEAR applications. Therefore, appropriate consideration must be given to surfactant sorption and HOC partitioning to immobile versus mobile phases when using surfactants to remediate contaminated subsurface systems.Solution chemistry effects on surfactant micelle formation, surfactant sorption on kaolinite, and phenanthrene partitioning to surfactant micelles and sorbed surfactants were studied. For the anionic surfactant SDS, cmc values decreased with increasing ionic strength but were unaffected by pH changes. For the nonionic surfactant Tween 80, the cmc was unaffected by pH and ionic strength changes. SDS sorption on kaolinite showed strong pH and ionic strength dependency: sorption increased as pH decreased and ionic strength increased, respectively. For Tween 80, only pH changes affected its sorption on kaolinite. Phenanthrene Kmic values increased with increasing ionic strength for SDS but were not affected by changes in pH. For Tween 80 Kmic values, no pH or ionic strength effect was observed. Phenanthrene distribution coefficients (KD) between the solid and aqueous phases varied as a function of solution chemistry and were primarily dependent on the concentration of surfactant that was sorbed. Organic carbon-normalized partition coefficients (KOC) of the sorbed surfactants showed a much greater affinity for phenanthrene than that predicted for natural organic matter (NOM). For sorbed SDS aggregates, KOC values fell into two general regions depending on whether the pH was above or below the point of zero charge (pzc) of kaolinite. Plausible structural differences for sorbed SDS aggregates were used to explain these regional KOC values. A one-dimensional numerical model was developed to simulate the performance of SEAR applications for saturated subsurface systems containing adsorbed HOCs. The model incorporated temporally and spatially dependent HOC and surfactant mass balance equations to compute distributions in the aqueous, micellar, sorbed surfactant, and subsurface solid phases. In particular, the model accounted for losses of surfactant by sorption to the subsurface media and for the subsequent partitioning of HOCs to sorbed surfactant. Parameter values for the model were estimated from experimental rate and equilibrium data from the literature, and sensitivity analysis was conducted to evaluate the model performance and potential SEAR applications. Simulation results showed that the relative affinity of HOCs and surfactants for the immobile subsurface solid phase (i.e., the respective retardation factors) is critical for determining whether contaminant desorption can be enhanced by surfactants. For example, under the conditions simulated, removal of phenenthrene and naphthalene from a representative sandy (i.e., low organic carbon) aquifer was actually hindered by flushing with surfactant solutions, whereas for more hydrophobic contaminants (e.g., pyrene) surfactant addition enhanced HOC removal. Likewise, an increase in the organic carbon content of the subsurface solid phase increased the effectiveness of SEAR processes. The important rate and equilibrium model parameters evaluated provided useful guidelines for the design and application of SEAR processes for contaminated subsurface systems and for interpreting SEAR-related studies.Partitioning studies of HOCs to hydroxypropyl-beta-cyclodextrin (HPCD) and one-dimensional transport simulations were conducted to evaluate the feasibility of using HPCD to remove sorbed HOCs in SEAR applications. HOC partitioning to HPCD was very fast, with over 95% of the complexation occurring within 10 min. Some influence of solution chemistry and HOC concentration on HOC-HPCD complex formation coefficients was observed; in general, the magnitude of the effects was similar to that observed for Tween 80 but much less than that for SDS. HPCD sorption on kaolinite as quantified by both a fluorescence technique and total organic carbon measurements was negligible, indicating no significant affinity of HPCD for the solid phase. Although the HOC solubilization capability of HPCD was lower than that of conventional surfactants such as SDS and Tween 80, transport simulations showed that HPCD can be effective in removing sorbed HOCs from a model subsurface environment, primarily because of its negligible sorption to the solid phase (i.e., all HPCD added facilitates HOC elution). However, in contrast with SDS and Tween 80, HPCD becomes relatively less effective for HOC partitioning with increasing HOC size and hydrophobicity. Therefore, comparisons between HPCD and conventional surfactants for enhanced remediation applications must consider the specific HOC(s) present and the potential for surfactant material losses to the solid phase as well as other generally recognized considerations such as material costs and potential toxicological effects. Removal of HOCs from saturated low-permeability subsurface environments using a solubility-enhanced EK remediation process was demonstrated for a model system. Phenanthrene, HPCD, and kaolinite were selected as a representative HOC, HOC solubility-enhancing agent, and model clay soil, respectively. EK column experiments were conducted under various operating conditions, and the results were interpreted in terms of the EK properties and expected phenanthrene solubilization of the test systems. No significant effects of HPCD on the EK properties of kaolinite were observed. Initial pore solution pH values dictated the initial electroosmotic flow (EOF) and charge flow rates through the test samples. However, with increasing EK operating times, low pH values (i.e., near or below the pzc of kaolinite) dominated over most of the column length in unbuffered systems, thereby decreasing the EOF and charge flow rates with time. To minimize these adverse effects, pH control of the anode reservoir with a Na2CO3 buffer was used to keep EOF and charge flow rates high. EK experiments using HPCD solutions showed greater phenanthrene removal from the kaolinite samples, and the removal efficiency depended on the HPCD concentration used. Longer EK operating times without pH control were generally not beneficial for removing phenanthrene because of the low EOF rates obtained after 3 days. The best overall phenanthrene removal was obtained by flushing the anode reservoir with a high HPCD concentration prepared in the Na2CO3 buffer solution. The results obtained showed that an EK process combined with HPCD flushing and pH buffering may be a good remediation alternative for removing HOCs from low-permeability subsurface environments. To parallel the work using Tween 80, SDS and HPCD, experiments were conducted to determine if naturally-occurring organic matter (NOM) can be utilized to remediate contaminated subsurface environments. When NOM adsorbs to mineral surfaces, it undergoes both a fractionation process and macromolecular structural/conformational changes. Therefore, estimating organic carbon-normalized partition coefficients (Koc) for pollutants based on a bulk extracted NOM will not give accurate Koc values in a remediation process. Instead, different Koc values must be considered, such as Koc(ads) derived from mineral-bound NOM, Koc(bulk) using bulk NOM, and Koc(res) from the residual NOM left in solution after NOM sorption has been completed. HOC binding coefficients by NOM size fractions and the sorption capacities of different NOM size fractions onto minerals were determined to provide background information for the effect of NOM sorption on Koc and to validate the variance of Koc by NOM size fractionation. In addition, NOM fractionation upon sorption to minerals was examined in terms of NOM size (e.g., molecular weight) and NOM sorption mechanisms. For organic contaminant sorption to mineral-bound NOM in low organic carbon systems, possible NOM conformational changes were examined by comparing the Koc values of the adsorbed vs. nonadsorbed original NOM. Finally, solution chemistry effects on the above processes were examined in a series of systematic studies.NOM sorption isotherms looked similar to Langmuir-type isotherms, consistent with previous studies. NOM size fractionation upon adsorption was investigated using size exclusion chromatography (SEC) by comparing the molecular weight of NOM remaining in solution after sorption (residual NOM) with that of the original bulk NOM. For kaolinite, the larger NOM fractions were preferentially adsorbed to the mineral and the lower molecular weight fractions were left behind in the residual aqueous phase, consistent with hydrophobic bonding. Binding coefficients of pyrene by residual NOM as a function of the equilibrium residual concentration were determined. In general, lower pyrene binding by the residual NOM was observed compared to the original bulk NOM. A lower extent of binding occurred because the lower molecular weight fractions were left behind in solution which then exhibited lower Koc values. Koc values for adsorbed NOM were determined as a function of foc. Generally, the values were lower than the one obtained by the original NOM prior to adsorption, suggesting that conformational changes occurred upon adsorption and that this structural change resulted in decreased pyrene binding.
Journal Articles on this Report: 5 Displayed | Download in RIS Format
| Other subproject views: | All 13 publications | 6 publications in selected types | All 5 journal articles |
| Other center views: | All 472 publications | 140 publications in selected types | All 123 journal articles |
| Type | Citation | ||
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Ko SO, Schlautman MA, Carraway ER. Effects of solution chemistry on the partitioning of phenanthrene to sorbed surfactants. Environmental Science & Technology November 15, 1998; 32(22): 3542-3548. |
R826694C635 (Final) R822721C635 (1999) |
not available |
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Ko SO, Schlautman MA, Carraway ER. Partitioning of hydrophobic organic compounds to sorbed surfactants. 1. experimental studies. Environmental Science & Technology September 15, 1998; 32(18): 2769-2775. |
R826694C635 (Final) R822721C635 (1999) |
not available |
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Ko SO, Schlautman MA. Partitioning of hydrophobic organic compounds to sorbed surfactants. 2. model development/predictions for surfactant-enhanced remediation applications. Environmental Science & Technology 1998; 32(14): 2776-2781. |
R826694C635 (Final) R822721C635 (1999) |
not available |
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Ko SO, Schlautman MA, Carraway ER. Partitioning of hydrophobic organic compounds to hydroxypropyl b-cyclodextrin: experimental studies and model predictions for surfactant-enhanced remediation applications. Environmental Science & Technology 1999; 33(16): 2765-2770. |
R826694C635 (Final) R822721C635 (1999) |
not available |
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Ko SO, Schlautman MA, Carraway ER. Cyclodextrin-enhanced electrokinetic removal of phenanthrene from a model clay soil. Environmental Science & Technology 2000; 34(8): 1535-1541. |
R826694C635 (Final) R822721C635 (1999) |
not available |
organic contaminants, clay soils, surfactants, cyclodextrins, NOM, electrokinetic remediation. , POLLUTANTS/TOXICS, Water, Scientific Discipline, Waste, Remediation, Engineering, Chemistry, & Physics, Chemicals, Environmental Engineering, Environmental Chemistry, Chemistry and Materials Science, Contaminated Sediments, heavy metal contamination, heavy metals, chlorinated hydrocarbons, soil remediation, lead, chemical transport, surfactants, groundwater, contaminated sediment, DNAPLs, contaminant transport, contaminant removal, mercury, contaminated soil, hydrophobic pollutants, sediment treatment, electrokinetics, low permeability, chemical contaminants, vadose zone, electrode technology, chlorinated organic compounds
Progress and Final Reports:
Original Abstract
Main Center Abstract and Reports:
R828598 Gulf Coast HSRC (Lamar)
Subprojects under this Center:
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R822721C529 Environmentally Acceptable Endpoints: Risk Based Remediation Using Bioremediation
R822721C552 Degradative Solidification/Stabilization Technology for Chlorinated Hydrocarbons
R822721C569 Treatment and Product Recovery: Supercritical Water Oxidation of Nylon Monomer Manufacturing Waste
R822721C620 Colloidal Fouling of Membranes: Implications in the Treatment of Textile Dye Wastes and Water Reuse
R822721C626 Catalytic Hydroprocessing of Chlorinated Organics
R822721C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
R822721C630 Microbial Cometabolism of Recalcitrant Chemicals in Contaminated Air Streams
R822721C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R822721C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
R822721C636 Transformation Reactions of Nitroaromatic and Nitrogen Heterocyclic Compounds on Granular Activated Carbon (GAC) Surfaces: Enhancement of GAC Adsorption in Natural and Engineered Environmental Systems
R822721C640 Environmentally Friendly Organic Synthesis in Supercritical Fluids
R822721C645 Development and Evaluation of an Integrated Model to Facilitate Risk-Based Corrective Action at Superfund Sites
R822721C651 Adjustable Biopolymer Chelators for Cadmium, Lead and Mercury
R822721C653 New Electrochemically Smart Catalysts for Hazardous Waste Management and Development of Capillary Electrophoresis for Analysis of their Products
R822721C655 Soil Sampling in South Alabama Oil Fields
R822721C659 Subsurface Contamination Site Characterization via a Computer-Aided Visual Tool
R822721C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R822721C663 Soil Remediation with Ultra-High-Efficiency Hydrocyclones
R822721C669 Solid Acid Catalyzed Alkylation in Supercritical Fluids
R822721C679 Regeneration/Reactivation of Carbon Adsorbents by Radio Frequency (RF) Induction Heating
R822721C687 Improved Halogen Resistance of Catalytic Oxidation
R822721C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R822721C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R822721C700 Effects of Natural and Cyclic Variations on Contaminant Fate and Transport
R822721C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C620 Colloidal Fouling of Membranes: Implications in the Treatment of Textile Dye Wastes and Water Reuse
R826694C625 Enhanced Treatment of DNAPLs Contaminated Soils and Groundwater Using Biosurfactants: In-Situ Bioremediation
R826694C626 Catalytic Hydroprocessing of Chlorinated Wastes
R826694C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
R826694C629 Biofiltration of BTEX in Petroleum-Contaminated Soil Remediation Off-Gas
R826694C630 Microbial Cometabolism of Recalcitrant Chemicals in Contaminated Air Streams
R826694C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R826694C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
R826694C636 Transformation Reactions of Nitroaromatic and Nitrogen Heterocyclic Compounds on Granular Activated Carbon (GAC) Surfaces: Enhancement of GAC Adsorption in Natural and Engineered Environmental Systems
R826694C640 Environmentally Friendly Organic Synthesis in Supercritical Fluids
R826694C645 Development and Evaluation of an Integrated Model to Facilitate Risk-Based Corrective Action at Superfund Sites
R826694C651 Adjustable Biopolymer Chelators for Cadmium, Lead, and Mercury Remeidation
R826694C659 Subsurface Contamination Site characterization Via a Computer-Aided Visual Tool
R826694C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R826694C669 Solid Acid Catalyzed Alkylation in Supercritical Reaction Media
R826694C679 Regeneration and Reactivation of Carbon Adsorbents by Radio Frequency Induction Heating
R826694C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R826694C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R826694C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R826694C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R826694C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R826694C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R826694C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R826694C731 Development and Application of a Real-Time Optical Sensor for Atmospheric Formaldehyde
R826694C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C001 Field Study Abstract: A Model of Ambient Air Pollution in Southeast Texas Using Artificial Neural Network Technology
R828598C002 Hollow Fiber Membrane Bioreactors for Treating Water and Air Streams Contaminated with Chlorinated Solvents
R828598C003 Fugitive Emissions of Hazardous Air Pollutants from On-Site Industrial Sewers
R828598C004 Biofiltration Technology Development
R828598C005 A Risk-Based Decision Analysis Approach for Aquifers Contaminated with DNAPLs
R828598C006 In-Situ Remediation for Contaminated Soils Using Prefabricated Vertical Drains
R828598C007 Membrane Technology Selection System for the Metal Finishing Industry
R828598C008 Sequential Environments for Enhanced Bioremediation of Chlorinated Aliphatic Hydrocarbons
R828598C009 Waste Minimization in the Magnetic Tape Industry: Waterborne Coating Formulations for Magnetic Tape Manufacture
R828598C010 Soil Remediation by Agglomeration with Petroleum Coke
R828598C011 Recovery of Dilute Phosphoric Acid in Waste Streams Using Waste Gas Ammonia: The Regenerative MAP/DAP Process
R828598C012 Stochastic Risk Assessment for Bioremediation
R828598C013 Selective Removal of Heavy Metals from Wastewater by Chelation in Supercritical Fluids
R828598C014 Optimization of Treatment Technologies for Detoxification of PCB Contaminated Soils
R828598C015 Wastewater Remediation by Catalytic Wet Oxidation
R828598C016 Permanence of Metals Containment in Solidified and Stabilized Wastes
R828598C017 Combustion Enhancement by Radial Jet Reattachment - Low Generation of Hazardous Gases and High Thermal Efficiency
R828598C018 A Process To Convert Industrial Biosludge and Paper Fines to Mixed Alcohol Fuels
R828598C019 Homogeneous Catalysis in Supercritical Carbon Dioxide
R828598C020 Ultrasonic Enhancement of the Removal of Heavy Metals
R828598C021 The Binding Chemistry and Leaching Mechanisms of Advanced Solidification/Stabilization Systems for Hazardous Waste Management
R828598C022 Development of an Air-Stripping and UV/H2O2 Oxidation Integrated Process To Treat a Chloro-Hydrocarbon-Contaminated Ground Water
R828598C023 A Comparative Study of Siting Opposition in Two Counties
R828598C024 Sonochemical Treatment of Hazardous Organic Compounds II: Process Optimization and Pathway Studies
R828598C025 Laser Diagnostics of the Combustion Process within a Rotary Kiln Incinerator
R828598C026 Use of Inorganic Ion Exchangers for Hazardous Waste Remediation
R828598C027 Kaolinite Sorbent for the Removal of Heavy Metals from Incinerated Lubricating Oils
R828598C028 Destruction of Chlorinated Hydrocarbons in Process Streams Using Catalytic Steam Reforming
R828598C029 Integrated Process Treatment Train (Bioremediation {Aerobic/Anaerobic} and Immobilization) for Texas Soils Contaminated with Combined Hazardous Wastes
R828598C030 Photo-Oxidation by H2O2/VisUV of Off-Gas Atmospheric Emissions from Industrial and Environmental Remediation Sources
R828598C031 Concentrated Halide Extraction and Recovery of Lead from Soil
R828598C032 Biodegradable Surfactant for Underground Chlorinated Solvent Remediation
R828598C033 A Software Guidance System for Choosing Analytical Subsurface Fate and Transport Models Including a Library of Computer Solutions for the Analytical Models
R828598C034 Hydrodynamic Modeling of Leachate Recirculating Landfill
R828598C035 Measurement of Oxygen Transfer Rate in Soil Matrices
R828598C036 Sorbent Technology for Multipollutant Control During Fluidized Bed Incineration
R828598C037 Pollution Prevention by Process Modification Using On-Line Optimization
R828598C038 Pollution Prevention by Process Modification
R828598C039 Water Solubility and Henry's Law Constant
R828598C040 Transferring Technical Information on Hazardous Substance Research by Publishing on the World Wide Web
R828598C041 Stress Protein Responses to Multiple Metal Exposure in Grass Shrimp
R828598C042 Life-Cycle Environmental Costing for Managing Pollution Prevention in the Chemical and Petroleum Refining Industries: A Cross-Border Approach
R828598C687 Improved Halogen Resistance of Catalytic Oxidation Through Efficient Catalyst Testing
R828598C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R828598C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R828598C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R828598C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R828598C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R828598C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R828598C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R828598C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R828598C731 Development and Application of a Real Time Optical Sensor for Atmospheric Formaldehyde
R828598C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C743 Field Demonstration of Ultrasound Enhancement of Permeable Treatment Walls
R828598C744 Optical Fibers Coated With Titania Membrane/UV-Generating Crystal in a Distributed-Light Photoreactor for VOC Oxidation
R828598C749 Characterization and Modeling of Indoor Particulate Contaminants In a Heavily Industrialized Community
R828598C753 Adsolubilization and Photocatalysis in a Semiconducting Monolithic Reactor for Wastewater Treatment
R828598C754 Remote Detection of Gas Emissions in Industrial Processes
R828598C759 Searching for Optimum Composition of Phosphogypsum: Fly ash: Cement Composites for Oyster Culch Materials
R828598C761 Development of a Phytologically-Based Biosorptive Water Treatment Process
R828598C766 Chlorinated Solvent Impact and Remediation Strategies for the Dry Cleaning Industry
R828598C769 Soil/Sediment Remediation by Hot Water Extraction Combined with In-Situ Wet Oxidation
R828598C771 Fluoracrylate Polymer Supported Ligands as Catalysts for Environmentally Benign Synthesis in Supercritical Fluids
R828598C774 The Feasibility of Electrophoretic Repair of Impoundment Leaks
R828598C777 Surfactant Enhanced Photo-oxidation of Wastewaters
R828598C778 Stationary Power Generation Via Solid Oxide Fuel Cells: A Response to Pollution and Global Warming
R828598C786 Photocatalytic Recovery of Sulfur and Hydrogen From Hydrogen Sulfide
R828598C787 Biosurfactant Produced from Used Vegetable Oil for removal of Metals From Wastewaters and Soils
R828598C789 Genetic Engineering of Enzymatic Cyanide Clearance
R828598C791 Characterizing the Intrinsic Remediation of MTBE at Field Sites
R828598C799 Simultaneous Water Conservation/Recycling/Reuse and Waste Reduction in Semiconductor Manufacturing
R828598C801 Building Defined Mixed Cultures To Biodegrade Diverse Mixtures Of Chlorinated Solvents
R828598C802 Engineering of Nanocrystal Based Catalytic Materials for Hydroprocessing of Halogenated Organics
R828598C807 Commercial Demonstration of Hydrogen Peroxide Injection to Control NOx Emissions from Combustion Sources
R828598C809 Evaluating Source Grouting and ORC for Remediating MTBE Sites
R828598C810 Application of Total Cost Assessment To Process Design In the Chemical Industry
R828598C846 Quantitative Demonstration of Source-Zone Bioremediation in A Field-Scale Experimental Controlled Release System
R831276C001 DNAPL Source Control by Reductive Dechlorination with Fe(II)
R831276C002 Arsenic Removal and Stabilization with Synthesized Pyrite
R831276C003 A Large-Scale Experimental Investigation of the Impact of Ethanol on Groundwater Contamination
R831276C004 Visible-Light-Responsive Titania Modified with Aerogel/Ferroelectric Optical Materials for VOC Oxidation
R831276C005 Development of a Microwave-Induced On-Site Regeneration Technology for Advancing the Control of Mercury and VOC Emissions Employing Activated Carbon
R831276C006 Pollution Prevention through Functionality Tracking and Property Integration
R831276C007 Compact Nephelometer System for On-Line Monitoring of Particulate Matter Emissions
R831276C008 Effect of Pitting Corrosion Promoters on the Treatment of Waters Contaminated with a Nitroaromatic Compounds Using Integrated Reductive/Oxidative Processes
R831276C009 Linear Polymer Chain and Bioengineered Chelators for Metals Remediation
R831276C010 Treatment of Perchlorate Contaminated Water Using a Combined Biotic/Abiotic Process
R831276C011 Rapid Determination of Microbial Pathways for Pollutant Degradation
R831276C012 Simulations of the Emission, Transport, Chemistry and Deposition of Atmospheric Mercury in the Upper Gulf Coast Region
R831276C013 Reduction of Environmental Impact and Improvement of Intrinsic Security in Unsteady-state
R831276C014 Integrated Chemical Complex and Cogeneration Analysis System: Greenhouse Gas Management and Pollution Prevention Solutions
R831276C015 Improved Combustion Catalysts for NOx Emission Reduction
R831276C016 A Large-Scale Experimental Investigation of the Impact of Ethanol on Groundwater Contamination
R831276C017 Minimization of Hazardous Ion-Exchange Brine Waste by Biological Treatment of Perchlorate and Nitrate to Allow Brine Recycle
R831276C018 Integrated Chemical Complex and Cogeneration Analysis System: Greenhouse Gas Management and Pollution Prevention Solutions