Tech Brief Fact Sheets
The National Drinking Water Clearinghouse (NDWC)
Download Latest Tech Brief:
Biofilm Control in Distribution Systems, Summer 2008 |
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NDWC's drinking water "Tech Briefs" are four-page fact sheets included
in On Tap magazine. Each fact sheet provides concise, technical
information about a drinking water treatment technology or issue relevant
to small systems."Tech Briefs" are written for drinking water professionals,
particularly small system operators. Tables and descriptive illustrations
are provided, as well as sources for more information.
Download Our Tech Brief Fact Sheets, Free
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How To Order
A Tech Brief Fact Sheets Package is available. The package holds all the current Tech Briefs in print and new selections can be added to the package as they become available. To order the packet request item Product # DWPKOM36. Price varies and shipping charges apply. e-mail us at info@mail.nesc.wvu.edu or call (800) 624-8301.
PDF files may be downloaded for free below.
- Biofilm Control in Distribution Systems (Order #DWFSOM124) / Summer 2008 - A biofilm is a surface deposit of bacteria, other microorganisms, and organic and inorganic materials that accumulate within a slime layer. Biofilms can form on solid and liquid surfaces when nutrients and water are present. Much like the plaque that forms on teeth, biofilms also form inside drinking water distribution systems and can sometimes cause a number of problems.
- Calibrating Liquid Feed Pumps (Order #DWFSOM105) / Spring 2008 - Liquid feeder pumps are used to inject various chemicals needed for effective water and wastewater treatment. Calibrating these pumps helps control and optimize feeding rates, which in turn provides better water quality at a lower cost. This Tech Brief discusses how to calibrate liquid feed pumps.
- Basic Water and Wastewater Formulas (Order #DWFSOM103) / Winter 2008 - Operators obtaining or maintaining their certification must be able to calculate complex formulas and conversion factors. This Tech Brief provides basic examples of these formulas and conversion factors.
- Please Note: The fact sheets below are listed in alphabetical order. Click on the link to download the pdf file of the fact sheet listed. The product order numbers are provided if you wish to order a hard copy.
- To order any or all fact sheets call (800) 624-8301 or e-mail us at info@mail.nesc.wvu.edu.
- Chlorination (Order #DWFSOM68) - Many water treatment plants have altered their disinfection strategies because of regulation changes concerning disinfection byproducts. Nevertheless, chlorination remains the most cost-effective and reliable disinfection method available.
- Corrosion Control (Order #DWFSOM52) - This fact sheet discusses various methods for controlling corrosion, including design considerations, water quality modifications, corrosion inhibitors, cathodic protection, and coatings and linings.
- Cross Connection and Backflow Prevention (Order #DWFSOM58) - Examinesthe problems associated with cross connections and backflow and provides practical solutions for eliminating them with this fact sheet.
- Cross-Connection Poster (Order #DWFSOM98) - Plumbing cross connections can link a potable water supply to a contamination source, causing a serious public health hazard. Cross connections can be controlled, but it takes vigilance and knowledge to carry out a good crossconnection control program. This poster illustrates some mechanical devices and methods used to control cross connections in commercial and industrial applications as well as for homeowners.
- Development of Low-Cost Treatment Options for Arsenic Removal in Water Treatment Facilities (Order #DWFSOM94) - Illinois State Water Survey and University of Illinois researchers experimented with different combinations of chemical additives and steps along the treatment process.
- Diatomaceous Earth (DE) Filtration for Drinking Water (Order #DWFSOM39) - This fact sheet discusses DE filtration, giving an explanation of the process, its history, monitoring and operating requirements, and sources of more information.
- Disinfection (Order #DWFSOM50) - The NDWC provides an explanation of disinfection as a drinking water treatment, the regulations governing it, the advantages and disadvantages of using it, and disinfection methods.
- Filter Backwashing (Order #DWFSOM83) - Backwashing a water system's filters is not only vital to the life of the filter, it's fundamental to the quality of the water coming out of the filter. Sooner or later, all filters need to be backwashed or replaced.
- Filtration (Order #DWFSOM51) -Filtration is the process of removing suspended solids from water by passing the water through a permeable fabric or porous bed of materials. Surface water and groundwater under the influence of suface water are subject to contamination from many sources, so federal and state laws require many water systems to filter their water. Several methods of filtrations are discussed.
- Fire Hydrant O and M Program How To (Download Only) - The single most important thing about having fire hydrants is that they advertise "Fire Protection!" Communities expect that at a moment's notice, day or night, in any weather, the hydrant will supply sufficient water to extinguish a fire.
- How to Operate and Maintain Manganese Greensand Treatment Units (Download Only) - As one remote West Virginia school discovered, these treatment units are effective in removing iron and manganese from drinking water—provided that they are installed correctly and maintained properly.
- Ion Exchange and Dimineralization (Order #DWFSOM46) - Natural organic materials and synthetic organic chemicals might be present in water supplies, especially from surface water sources, causing taste, odor, or color problems in a community's drinking water. This Tech Brief discusses technologies most suited for removing organic contaminants in drinking water systems.
- Iron and Manganese Removal (Order #DWFSOM42) - Iron and manganese are common in groundwater supplies used by many small water systems. Exceeding the suggested maximum contaminant levels usually results in discolored water, laundry, and plumbing fixtures. This, in turn, results in consumer complaints and a general dissatisfaction with the water utility. Examine iron and manganese with an overview of removal techniques.
- Jar Testing (Order #DWFSOM73) - Jar testing is a pilot-scale test of the treatment chemicals used in a particular water plant. It simulates the coagulation/flocculation process in a water treatment plant and helps operators determine if they are using the right amount of treatment chemicals, and, thus, improves the plant's performance.
- Leak Detection and Water Loss Control (Order #DWFSOM38) -Utilities can no longer tolerate inefficiencies in water distribution systems and the resulting loss of revenue associated with underground water system leakage. Increases in pumping, treatment and operational costs make these losses prohibitive. To combat water loss, many utilities are developing methods to detect, locate, and correct leaks.
- Lime Softening (Order #DWFSOM41) - Hard water causes scaling problems in water heaters, and soap does not lather well in hard water. Therefore, some water utilities soften water to improve its quality for domestic use.
- Line Pigging (Order #DWFSOM96) - Line pigging is an internal pipe-cleaning process used to remove biofilms or other foreign matter from the inside of water pipes. If performed correctly, line pigging will renew the flow rates to restricted piping systems and reduce pumping pressures
- Locating Distribution Lines (Order #DWFSOM85) - Finding water distribution lines can be a daunting task. Fortunately, there are several techniques for finding your pipes. As-built drawings, locating devices, geophones, and tapping the expertise of previous employees as useful methods for locating distribution lines are all part of this TB.
- Membrane Filtration (Order #DWFSOM43) - A semipermeable membrane is a thin layer of material capable of separating substances when a driving force is applied across the membrane. Once considered a viable technology only for desalination, membrane processes are increasingly employed for removal of bacteria and other microorganisms, particulates, and natural organic material, which can impart color, taste, and odors to water and can react with disinfectants to form disinfection byproducts.
- Organic Removal (Order #DWFSOM47) - Natural organic materials and synthetic organic chemicals might be present in water supplies, especially from surface water sources, causing taste, odor, or color problems in a community's drinking water. Technologies most suited for organic contaminant removal in drinking water systems are discussed.
- Ozone (Order #DWFSOM44) - New water treatment goals for disinfection byproducts (DBP) and for microbial inactivation increase the need to consider new disinfection technologies. Ozone is an attractive alternative. This technology has evolved and improved in recent years, thereby increasing its potential for successful application.
- Package Plants (Order #DWFSOM48) - Small communities that face financial problems purchasing and maintaining conventional drinking water treatment systems often opt to install a package plant, an alternative to conventional in-ground treatment technology.
- Point-of-Use/Point-of-Entry Systems (POU/POE) - Numerous households use point-of-use/point-of-entry (POU/POE) systems primarily to deal with aesthetic concerns, such as taste and odor. In certain situations, using POU/POE systems to provide safe drinking water to a system's customers is not an individual's choice, but that of the water system cooperating with regulatory authorities. This Tech Brief only discusses POU/POE treatment options that meet Safe Drinking Water Act (SDWA) water quality requirements.
- TB Poster: Treatment Technologies for Small Drinking Water Systems (Order #DWFSOM37)- This poster, provided by the NDWC, discusses many of the small system treatment technologies reviewed in the Tech Briefs, including membrane filtration, disinfection, and iron and manganese removal. The poster also includes tables that further explain the technologies.
- Preventing Well Contamination (Order #DWFSOM57) - Wells need to be sited and built to prevent groundwater contamination. This Tech Brief presents tips about how to site a well and includes information about design issues; material selection and location, such as screens and filter pack; appropriate well sealing methods; and using pitless adaptors.
- Pumps (Order #DWFSOM56) - Whether moving source water to the treatment plant, getting treated water to storage facilities, or injecting chemicals during the treatment process, pumps fulfill a vital role in any water system.
- Quality Control in Construction Projects (Order #DWFSOM81) - Utility systems need infrastructure to last as long as possible. One way to ensure longevity is through quality control. To have good quality control in construction projects is to perform good inspections. You can inspect it now or fix it later.
- Repairing Distribution Line Breaks (Order #DWFSOM60) - Occasionally, water systems encounter situations where they must repair distribution system pipes. Corrosion and tuberculation (i.e., buildup of sediment, dirt, or rust) may have caused small leaks in the lines, or worse, a major line break may occur, creating an emergency situation. This Tech Brief discusses ways to manage these situations and outlines steps a utility may take to repair the distribution system.
- Radionuclides (Order #DWFSOM45) - Radionuclide contamination of drinking water is a significant health issue. Until now, manmade radioactivity in drinking water has not been a major problem; natural sources have been the primary cause of contamination. However, the potential for contamination exists throughout the country as releases from medical facilities or nuclear power plants may wind up in drinking water. Because of their potential health effects and widespread occurrence, natural radionuclides-including radon, radium, and uranium-cause much concern.
- Reservoirs, Towers, and Tanks (Order #DWFSOM15) - After water leaves the treatment plant but before it reaches the customer, it must be adequately and safely stored. Read this to explore the various aspects of water storage.
- Sanitary Surveys (Order #DWFSOM74) - A sanitary survey is an inspection of a water system, including the water source, facilities, equipment, operation, and maintenance. Usually conducted by a member of the state primacy agency, the purpose of these mandatory surveys is to help prevent and correct water system deficiencies.
- Simultaneous Compliance with Drinking Water Regulations (Order #DWFSOM95) - Certain U.S. drinking water regulations, in particular the Stage 1 and 2 Disinfectants/Disinfection By-Products Rules and the Long-Term 1 and 2 Enhanced Surface Water Treatment Rules, have the potential to conflict with each other, as well as with other regulations such as the Lead and Copper Rule and the Total Coliform Rule. This means that small system operators cannot simply comply with these mandates individually, but must consider how changing their treatment process to meet one rule might affect compliance with other rules. Read this to find information and strategies that effectively comply with those regulations that are most likely to conflict with one another.
- Slow Sand Filtration (Order #DWFSOM40) - First used in the U.S. in 1872, slow sand filters are the oldest type of municipal water filtration. Today, they remain a promising treatment method for small systems with low turbidity or algae-containing source waters. Slow sand filtration does not require pretreatment or extensive operator control, which can be important for a small system operator with several responsibilities.
- System Control and Data Acquisition (Order #DWFSOM20) - SCADA systems are recognized as reliable and efficient methods of information management in water treatment facilities. Functions they perform include remote monitoring of well levels and pump control, flows, tank levels, pressures in storage tanks, and water quality characteristics, such as pH, turbidity, and chlorine residual.
- Taste and Odor Control (Order #DWFSOM88) - Complaints about the taste and smell of drinking water are all too common for many systems. This Tech Brief examines common taste and odor problems and provides techniques for dealing with them in the treatment plant.
- Turbidity Control (Order #DWFSOM89) - Describes treatment technologies and issues for drinking water professionals, discusses turbidity control. Often described as the cloudiness observed in source water, turbidity can hinder treatment methods. Examine turbidity and implications with the phenomenon from source to distribution.
- Ultraviolet Disinfection (Order #DWFSOM53) - Using ultraviolet (UV) light for drinking water disinfection dates back to 1916 in the U.S. UV disinfection involves exposing contaminated water to radiation from UV light. The treatment works because UV light penetrates an organism's cell walls and disrupts the cell's genetic material, making reproduction impossible.
- Valves (Order #DWFSOM21) - Valves direct, start, stop, mix, or regulate the flow, pressure, or temperature of a fluid. Many types of valves exist. This Tech Brief examines the most common types of valves, problems that may be encountered (such as cavitation, flashing, choked flow, and water hammer effects), operation and maintenance requirements, and safety issues with respect to security.
- Valve Exercising (Order #DWFSOM97) - Every water system has valves--devices that regulate, stop, or start the flow of water in the distribution lines. Being able to operate these valves at a moment's notice is extremely important. In an emergency, sections of a distribution system may need to be shut down without delay. However, if a valve is not used over a period of time it can seize-up from corrosion and get stuck, making the valve inoperable.
- Water Conservation Measures (Order #DWBLPE74) - This fact sheet considers the role of water conservation as an integral part of long-term resource planning. It might be more appropriate to use the term "water demand management." Traditional water supply management seeks to provide all the water the public wants, which, in some sections of the country, translates to a constant search for untapped sources.
- Water Hammer (Order #DWFSOM27) - This phenomenon is the momentary increase in pressure that occurs in a water system when there is a sudden change of direction or velocity of the water. These pressure fluctuations can be severe enough to rupture a water main.
- Water Meters (Order #DWFSOM67) - Any viable business must be able to determine how much product it is making and selling and if that product is profitable. Water is a business. And, the best way for a water utility to measure or account for the water produced and then sold is by using water meters. Explore different types of meters, their applications, and their importance for a water utility business.
- Water Quality in Distribution Systems (Order #DWFSOM25) - Water producers need to understand the sources of water quality degradation during the distribution process because, in addition to taste and odor problems that can occur, research also suggests that degraded water quality increases the risk of gastrointestinal illnesses.
- Water Treatment Plant Residuals Management (Order #DWFSOM49) - Water treatment plants produce a wide variety of waste products as well as safe drinking water. Examine residuals categories, major treatment processes, and the regulations that govern management of residuals in this TB.