\'/. United States Environmental Protection Agency Risk Reduction Engineering Laboratory Cincinnati OH 45268 Research and Development EPA/600/S2-89/027 Feb. 1990 £EPA Project Summary Point-of-Entry Drinking Water Treatment Systems for Superfund Applications Catherine D. Chambers and Thomas A. Janszen The U.S. Environmental Protection Agency (EPA) and State Superfund agencies need a technical assistance manual to assist their personnel in the selection of an effective drinking water treatment system for individual households in areas where the drinking water has been adversely affected by Superfund site con- taminants and no other alternative water supply is available or feasible. Commercially available water treat- ment systems for Individual house- holds are of two basic types: point-of- use (POU) and polnt-of-entry (POE). A POU device consists of equipment applied to selected water taps to reduce contaminants at each tap. A POE device consists of equipment to reduce the contaminants in the water distributed throughout that structure. This study was Initiated to collect monitoring, operation and mainte- nance, performance, and design data on existing Superfund POE water treatment systems. Evaluation of the collected data showed that existing data are not sufficient for the preparation of a technical assistance document to meet the objectives of EPA and State Superfund personnel. There is a need for additional study to develop a technical assistance document. Because most of the existing data and field experience related to POE water treatment is concerned with granular activated carbon filters and air strippers for the treatment of organic contaminants, the authors recommend that further detailed study center around these two technologies. This Project Summary was devel- oped by EPA's Risk Reduction En- gineering Laboratory, Cincinnati, ON, to announce key findings of the re- search project that Is fully docu- mented In a separate report of the same title (see Project Report or- dering information at back). Introduction Point-of-entry (POE) systems can take a variety of forms, entail the use of various technologies, and be used either singularly or in combination to address numerous water quality problems. Gen- erally, the three contaminant categories of concern are organic compounds, inorganic compounds, and microbio- logical agents. The most common POE systems for removal of organic chemicals involve the use of granular activated carbon (GAC) and/or aeration. Those used for removal of inorganic contam- inants can involve reverse osmosis (RO) or deionization (Dl). Systems used to eliminate microbiological agents may in- clude filtration (through ceramic filters), chemical disinfection, and ultraviolet (UV) irradiation. When properly selected, operated, and maintained, POE systems can be both effective and safe. Often, the operation and maintenance of installed units is critical to health protection. For example, GAC filters can act as a growth medium for bacteria. In some cases, water being treated with GAC may also require some type of disinfection (e.g., UV irradiation). Superfund-financed POE water treat- ment systems have been installed on individual household wells in which the well water has been contaminated with ------- toxic compounds from a Superfund site. These installations have been made on a case-by-case basis depending on the ability and resourcefulness of the persons involved. This report presents the findings of the study to evaluate POE water treatment systems for Superfund applications. It involved an assessment of the status of currently operating POE systems at Superfund or comparable sites and the collection and evaluation of available operating, performance, and design data for these systems. Based on this assessment, recommendations are made concerning the development of a technical assistance manual. Data collection consisted of contacting EPA Regional Superfund offices to identify sites where POE treatment is being used. Several State and local agencies also were contacted to obtain information related to State-supervised POE system installations. The available information consisted of monitoring data, system descriptions, some system de- sign details, and operation and main- tenance practices. Several suppliers/ manufacturers of the POE treatment systems also were contacted to obtain information on the design and operation of their systems. Data on GAG filter sys- tems and aeration systems were obtained from these sources. Conclusions Data collection activities resulted in the following general findings: • Existing Superfund applications of POE treatment systems are pri- marily located in EPA Regions 2, 3, and 5. • State and local agencies in Florida, Maine, New York, and New Jersey are also applying POE water treat- ment at sites with types and levels of contaminants similar to those found as a result of Superfund site contamination. • The application of POE treatment has occurred primarily at sites where organic contamination (i.e., chlorinated solvents, pesticides, and petroleum products) has affected drinking water supplies. • Granular-activated-carbon (GAG) filters and air stripping are the two most common POE technologies used for treating organic contaminants. • The use of GAG filters, either single units or two units in series, is successful in treating water contaminated with chlorinated sol- vents and pesticides. • Air stripping, either diffused or packed-tower aeration, is more effective than GAG for treating water contaminated with petroleum products. • In some cases, air stripping is used to pretreat water with elevated levels of solvents before the water passes through a GAG filter. This is done to extend the effective life of the carbon filter. • On individual wells in which radon contamination is a problem, POE treatment by air stripping is being used. Most of the existing Superfund appli- cations of POE water treatment were identified during this phase of the study. Some information relative to system de- sign and operation was identified; how- ever, the level of detail of the design in- formation (i.e., unit specifications) is somewhat lacking. System suppliers and designers have been either reluctant or unable to provide the type of information needed. In most cases, no quality control (QC) data on the analytical data obtained dur- ing Phase I were available, including test methods, protocols, and QC samples. Some samples were analyzed by field gas chromatographs to determine the presence or absence of contaminants. Although these data are useful for deter- mining contaminant exposure, they may not provide the level of confidence re- quired for the development of a technical assistance document. Recommendations Although the POE systems being ap- plied at Superfund or comparable sites are capable of effective treatment of the contaminants of concern, the design, de- velopment, operation, maintenance, and monitoring of these systems varies from site to site. There is a need for additional study to develop a technical assistance document. Because most of the existing data and field experience related to POE water treatment are concerned with GAG filters and air strippers for treatment of organic contaminants, it is recommended that further detailed study center around these two technologies for treatment of organics. The document user may need specific guidance on the following technical issues: • Design flow requirements for operating the POE system. • Sampling points of interest for t POE treatment systems. • Design life of activated carbon 1 the contaminants of concern. • Effect of contaminant mixtures i carbon life. • Cost-effectiveness of changing a tivated carbon frequently versi sampling and analysis to monitor f breakthrough. • Design considerations for spac restrictions in homeowner basements. • Minimum contact time for raw wati with GAG or air stripping systems. • Properties of activated carbon cril cal to designing a POE treatmei system (e.g., pore size, carbo mass, particle size). • Ground-water constituents that a feet GAG filter or air stripper effec tiveness or operation (e.g., dis solved solids, pH, heavy metal; hardness). • Spent carbon disposal practices. The full report was submitted in fulfill ment of Contract No. 68-03-3413 by PE Associates, Inc., under sponsorship of th< U.S. Environmental Protection Agency. ------- Catherine D. Chambers and Thomas A. Janszen are with PEI Associates, Inc., Cincinnati, OH 45246. tH?ry K. Stlnson is the EPA Project Officer (see below). The complete report, entitled "Point-of-Entry Drinking Water Treatment Systems for Superfund Applications," (Order No. PB 89-195 010/AS; Cost: $15.95, subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Risk Reduction Engineering Laboratory U.S. Environmental Protection Agency Cincinnati, OH 45268 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati OH 45268 BULK RATE POSTAGE & FEES PAID EPA PERMIT No. G-35 Official Business Penalty for Private Use $300 EPA/600/S2-89/027 000085836 DWRD OSIEPA REGION V LIBSftRY 230 S DEARBORN ST BW 1670 CHICAGO IL 60604 ------- |