United States Environmental Protection Agency Water Engineering Research Laboratory Cincinnati OH 45268 Research and Development EPA/600/S2-85/112 Jan. 1986 SER& Project Summary Point-Of-Use Treatment to Control Organic and Inorganic Contaminants in Drinking Water Gordon E. Bellen, Marc Anderson, and Randy A. Gottler Several communities using point-of- use (POU) treatment technology for drinking water contaminant removal were studied under a cooperative agreement between the U.S. Environ- mental Protection Agency (EPA) and the National Sanitation Foundation (NSF). Study sites included communi- ties in Pennsylvania and New Jersey using POU activated carbon devices for reduction of volatile halogenated or- ganics; Arizona and Illinois communi- ties using POU activated alumina devices for fluoride reduction; and an Illinois community using POU reverse osmosis devices for fluoride and dis- solved solids reduction. In addition, central treatment with activated alu- mina for fluoride reduction was evalu- ated at two operating plants in Arizona. At all locations, POU devices pro- vided effective treatment for several months of operation. Average esti- mated monthly costs per site for pur- chase, installation, and maintenance of treatment devices ranged from $4.25 to $6.23 for activated alumina and acti- vated carbon treatment, and were $12.48 for reverse osmosis. Although most POU installations operated with- out problems from the time of installa- tion, a few devices required unplanned service. Management of POU devices is necessary to ensure ongoing, effective treatment. This Project Summary was devel- oped by EPA's Water Engineering Re- search Laboratory, Cincinnati, OH, to announce key findings of research projects that are fully documented in three separate reports: "Defluoridation of Drinking Water in Small Communi- ties" {EPA/600/2-85/110). "Point-Of-Use Reduction of Volatile Halogenated Organics in Drinking Water" (EPA/600/ 2-85/109), and "Management of Point- Of-Use Drinking Water Treatment Sys- tems" (EPA/600/2-85/111} (see Project Report ordering information at back). Introduction Small communities with contami- nated drinking water supplies often lack the financial resources and technical ex- pertise to effectively deal with the prob- lem. High initial capital costs can pro- hibit construction of a central treatment system for contaminant removal in many cases. Constructing a new well or connecting to a neighboring water sup- ply may not be feasible. One alternative solution is treatment of contaminated water at the point-of-use (POU). Although POU treatment may present an efficient, cost effective solution to drinking water contamination, there may be potential problems associated with losing the level of control associ- ated with central treatment systems. When POU treatment is the selected al- ternative, a sound program for manage- ment of POU drinking water treatment systems is necessary to ensure that all sites receive the desired quality of drink- ing water. Procedures POU treatment was studied in several communities by monitoring existing in- stallations or by installing and monitor- ------- »ti ing new devices. All POU study sites used a form of the line-bypass approach to treatment. Line-bypass devices are designed to treat only water intended for consumption. With this approach, the cold water line is tapped to provide influent to a treatment device. A sepa- rate tap for treated water is provided at the sink. Site selection was based on commu- nity interest, quality of source water, lo- gistics for water sampling, and the ap- proach to treatment. POU devices were purchased from equipment manufac- turers or distributors and installed by licensed plumbing contractors. Water sample collectors were selected and trained by NSF. Collection, preserva- tion, and analysis of water samples were in accordance with prescribed EPA methods. Bacteriological quality of predevice and postdevice water was monitored at all POU sites with Standard Plate Counts (SPCs) and coliform enumera- tion. To simulate water that would be consumed if the faucet were not al- lowed to run before water was drawn, samples were collected from unflushed, undisinfected taps. For comparative purposes, samples were collected from disinfected taps that were flushed for 2 to 3 min. In some cases, samples were also collected from taps that were flushed for 1L. Cost information for POU treatment in the Illinois and Pennsylvania commu- nities was based on actual cost data col- lected during the project. Cost data from other sites were supplied by equipment manufacturers and/or municipalities. Maintenance costs for POU devices were calculated using manufacturers' rated service volumes and the average volume of treated water. In the Village of Silverdale, PA, 49 POU activated carbon (AC) devices, rep- resenting products from several manu- facturers, were installed and monitored for 14 months of operation for control of volatile organic chemicals (VOCs), most notably trichloroethylene (TCE) and tet- rachloroethylene (PCE). In the Lake Telemark subdivision of Rockaway Township, NJ, the township health de- partment and a manufacturer of POU AC devices began a pilot demonstration in 1981 by installing and monitoring devices in 12 homes with wells contam- inated with organics. Performance veri- fication and review of cost data were included in this study. Arizona communities using POU acti- vated alumina (AA) devices for fluoride reduction included Thunderbird Farms and Papago Butte Ranches, where sepa- rate distribution systems are provided for irrigation and domestic water. A por- tion of the domestic water is bypassed and treated with AA for potable uses. Domestic water boards for both com- munities provide installation, monitor- ing, and maintenance of treatment devices. POU treatment with AA for ar- senic and/or fluoride reduction was studied at two Arizona institutions, the Ruth Fisher Elementary School located near Tonopah and the You & I Trailer Park located new Wintersburg. At the three Illinois project sites, the public water systems are supplied by well water with high fluoride, alkalinity, and dissolved solids. Project demon- strations included installation and mon- itoring of 10 POU AA devices in Parkers- burg and 40 POU AA devices in Bureau Junction. In Emington, 47 low-pressure POU reverse osmosis (RO) devices were installed and monitored for 8 mo. These sites were the first applications of POU fluoride reduction at the community level in Illinois. Central AA treatment plants, located at Gila Bend and Palo Verde, AZ, pro- vided a basis for comparison of two small, but different sized, central facili- ties. The Gila Bend plant has been oper- ating since May 1978; the Palo Verde plant has been operating since Decem- ber 1979. In addition, a pilot study was performed in North Myrtle Beach, SC, to estimate AA central treatment costs. A •summary of all project sites appears in Table 1. Table 1. Site Summary Results and Discussion Volatile Halogenated Organics Reduction The major VOCs in Silverdale's water supply were TCE and PCE. POU devices reduced concentrations of these con- taminants to nondetectable levels (<0.001 mg/L) in 87 percent of the sam- ples collected over 14 mo. The mean volume treated during this period was 340 gal; maximum volume treated was 1130 gal. Devices were still in operation at the end of the study. Breakthrough, defined as detection of the same VOC in consecutive post- device samples from the same site at concentrations above 0.001 mg/L, did not occur for any device for TCE or PCE during 14 mo of sampling. However, trace concentrations of VOCs were de- tected intermittently in postdevice sam- ples from each model type; concentra- tions were generally below 0.005 mg/L. The most frequently measured post- device VOC was chloroform. Although the mean influent chloroform concen- tration was 12 times less than the mean TCE concentration, chloroform may break through before TCE. This is sup- ported by isotherm data typical for acti- vated carbon. The capital cost for POU AC treatment in Silverdale ($289) was an average cost of purchasing devices from several manufacturers (in quantity) and equip- ping them with product water meters. Maintenance costs included an average monthly repair cost per site of $1.43. Some POU devices required no mainte- nance during the study. In the Lake Telemark subdivision of Rockaway Township, 12 POU AC devices were installed on private well Site Gila Bend, AZ Palo Verde, AZ North Myrtle Beach, SC Thunderbird Farms, AZ Papago Butte, AZ Ruth Fisher School, AZ You & 1 Trailer Park, AZ Parkersburg, IL Bureau Junction, IL Emington, IL Silverdale, PA Rockaway Township, NJ Treatment Approach Central Central Central POU POU POU POU POU POU POU POU POU Treatment Process AA AA AA AA AA AA AA AA AA RO AC AC Application Fluoride Reduction Fluoride Reduction Cost Estimate for Fluoride Reduction Fluoride Reduction Fluoride Reduction Fluoride Reduction Fluoride & Arsenic Reduction Fluoride Reduction Fluoride Reduction Fluoride & Dissolved Solids Reduction Organics Reduction Organics Reduction ------- water supplies in October 1981. Only one of 21 postdevice samples collected from October 1982 through October 1983 contained detectable VOCs (0.004 mg/L TCE and 0.002 mg/L PCE). Eight sites were sampled during the 24th month of operation with no detectable VOCs in effluent samples. After 2 yr of service, the average cumulative volume treated was approximately 1650 gal, based on readings taken from a flow in- dicator on the device. A device sampled after reaching its estimated treatment capacity of 2000 gal produced water with no detectable VOCs. Equipment costs of POU AC devices in Rockaway ($225) were negotiated by the community during an initial phase of the pilot demonstration. No mainte- nance was reported during the 2-yr pilot demonstration period. A summary of results from demonstrations of POU AC devices in Silverdale and Rockaway Township appears in Table 2. Activated Alumina Defluoridation Several treatment runs from the AA central treatment plants were evaluated by collecting and analyzing water sam- ples and by reviewing plant records. Fluoride exchange capacities ranged between 1840 and 2600 grains/ft3 (4210- 5950 grams/m3) for Gila Bend and be- tween 2260 and 3540 grains/ft3 (5170- 7890 grams/m3) for Palo Verde. Average media attrition rates per regeneration were 1.2 percent of bed volume for Gila Bend and 2.8 percent for Palo Verde. Most media attrition appeared to occur during regeneration. Although the plant at Palo Verde demonstrated higher fluoride exchange capacity than at Gila Bend, operating costs were also higher. Central treat- ment production costs (amortized capi- tal costs plus operating costs) per 1000 gal were $0.45 for Gila Bend and $5.37 for Palo Verde. Higher chemical con- sumption rates (i.e., stronger regener- ant) and very low production con- tributed to the higher cost. The use of part-time, inexperienced operators at Palo Verde resulted in inefficient opera- tion at times. At North Myrtle Beach, a pilot demon-. stration was performed to develop a cost estimate for construction and oper- ation of central treatment facilities. Be- cause North Myrtle Beach's water sup- ply consists of 10 wells in dispersed locations, the proposed system was a Table 2. POU Activated Carbon Studies Participating Sites Service Area Type Mean Treated Water Use (gpd) Trichloroethylene (mean mg/L) 1 Predevice Postdevice 1,1,1-Trichloroethane (mean mg/L)1 Predevice Postdevice Costs Capital ($)2 To Customer ($/month)3 Silverdale, PA 49 central system with single family homes 1.0 0.080 <0.007 0.007 <0.007 289 5.98 Rockaway Township, NJ 12 private wells at single family homes 2.3 est. 0.125 <0.001 0.092 <0.007 255 4.23 ^Samples containing <0.001 mg/L were assigned a value of 0.0009 mg/L for calculation of the mean. 2Average of five manufacturers; includes equipment + installation costs. 3Capital, amortized at 10% for 20 years + maintenance. group of 10 small (200,000 gpd) central plants. Estimated production costs were $0.57 per 1000 gal. At Thunderbird Farms, several POU AA devices reduced influent fluoride levels effectively for periods exceeding 2 yr. Other AA devices operating at Thunderbird Farms had shorter service lives, attributed to media cementing and/or short-circuiting. At the You & I Trailer Park, raw water fluoride concen- tration was 15.7 mg/L and arsenic was 0.086 mg/L. A POU AA device effectively treated 2500 gal (330 bed volumes) be- fore fluoride breakthrough, demonstrat- ing the highest exchange capacity observed for POU devices (2300 grains/ ft3). Influent arsenic and silica concen- trations at Arizona POU sites generally were reduced to nondetectable levels beyond fluoride breakthrough. POU AA devices installed in Parkers- burg and Bureau Junction were equipped with valves; this allowed par- tial bypassing of raw water to provide optimal fluoride concentrations by blending treated and untreated water. Valve settings were controlled with a colorimetric test kit during sample col- lection. The effect of raw water alkalinity is demonstrated in the data from Illinois sites, which included a pilot demonstra- tion in Emington. The higher alkalinity at Parkersburg caused fluoride break- through at a lower mean cumulative bed volume (110 bed volumes) than at Emington (190 bed volumes). Break- through at Bureau Junction, with the lowest alkalinity, was not observed until 350 bed volumes. Part of the reduced capacity at Emington must be attributed to the accelerated flow (370 gpd) during the pilot study. Maintenance costs for POU AA devices were based on replacing the alumina cartridge when treated water fluoride levels reached the local Maxi- mum Contaminant Level (MCL). For Ari- zona, the MCL was 1.4 mg/L, and for the Illinois communities, it was 1.8-2.0 mg/ L. Summaries of results from Arizona and Illinois POU AA sites appear in Table 3 and Table 4, respectively. Low-Pressure Reverse Osmosis POU RO systems installed in Eming- ton used a spiral-wound polyamide RO membrane operated at line pressure. Pretreatment included granular acti- vated carbon (GAC) followed by a 5-|A prefilter. Product water was stored in a 2-gal pressurized tank. Reject water was bled through a capillary tube to the home drain line. Product water from the storage tank passed through a GAC pol- isher before being dispensed. Fluoride rejection averaged 86 per- cent, with total dissolved solids rejec- tion (TDS) averaging 79 percent. Rela- tively large ranges of rejection percentages were observed for all ana- lytes. This phenomenon did not corre- late with site, use rate, or collection date, but appeared to be due in part to a pressure drop across the prefilter as- sembly. Flow rates were measured for several RO devices during a site visit. Ranges of product and reject flow rates were 1.3 to 4.4 gpd and 16.1 to 27.8 gpd, respectively. Water temperatures and ------- pressures (measured at hose connec- tions) did not correlate with flow rates. Iron deposits in the well and distribution system fouled some GAC prefilters, cre- ating head loss across the pretreatment assembly. One GAC prefilter which had been fouled with iron deposits was re- moved, flushed, and reinstalled. The resulting 33 percent production rate increase was accompanied by a 29 percent increase in solids rejection, implying a constant flux of solids across the RO membrane, i.e., more water was produced for essentially the same mass of solids, resulting in higher quality water. The capital cost for POU RO at Eming- ton ($540) was an average of several manufacturers' quotes for devices, with and without pressurizing pumps, based on purchase of 40 to 50 units. The aver- age installation cost per unit of $68 (per- formed by an equipment dealer) was in- cluded. Costs for central RO treatment at Em- ington were estimated by soliciting a quote; they included approximately $60,000 for a central RO system (includ- ing mechanical and electrical installa- tion) and $60,000 for a concrete block building. Estimated operating costs per 1000 gal of product water included chemicals ($0.10), power for pumps ($0.36), membrane replacement every 5 yr ($0.18), and prefilter cartridge re- placement ($0.02). Monthly customer costs were based on the design flow of 16,500 gpd. A summary of the Emington RO demonstration appears in Table 5. Bacteriological Sample Results Standard Plate Counts (SPCs) from the AC sites indicated microbial colo- nization of the carbon bed. In Silverdale, unflushed postdevice samples had mean densities two orders of magni- tude higher than corresponding pre- device samples. If 1L of water was flushed from the line before sampling, postdevice samples had mean densities only one order of magnitude higher than predevice samples. Samples of water collected after 2 min of flushing had SPC densities comparable to sam- ples of water from the distribution sys- tem. In Rockaway, flushing and disin- fecting the tap reduced SPCs by one order of magnitude. Data collected dur- ing the study did not indicate coloniza- tion of AC devices by coliform orga- nisms. Positive coliform results in Silverdale were obtained from 4 of 176 postdevice samples collected from flushed, disinfected taps. Postdevice re- Table 3. Arizona POU Activated Alumina Studies Participating Sites Service Area Type Influent Fluoride (mg/L) Influent Alkalinity (mg/L as CaCO3) Mean Treated Water Use (gpd) Volume to Breakthrough1 (gallons) (bed volumes) Costs Capital ($) To Customer ($/month)2 Thunderbird Farms 8 central system with single family homes 2.6 200 1.4 >1540 >4W 225 4.44 Papago Butte 1 subsystem for several families 2.6 200 18.5 9500 1270 350 4.60 Ruth Fisher School 1 institution 4.4 80 8.5 WOO 270 360 12.00 You&l Trailer Park 1 institution 75.7 40 5.5 2500 330 230 6.27 1 Defined as the point where postdevice fluoride concentration reached the local MCL. 2Capital, amortized at 10% for 20 years + maintenance. Table 4. Illinois POU Activated Alumina Studies Parkersburg Participating Sites Service Area Type Influent Fluoride (mg/L) Influent Alkalinity (mg/L as CaCO3) Mean Treated Water Use (gpd) Volume to Breakthrough1 (gallons) (bed volumes) Costs Capital ($) To Customer ($/month)2 10 central system with single family homes 6.6 1000 0.6 400 110 273 6.23 Bureau Junction 40 central system with single family homes 6.0 540 0.8 1300 350 285 4.25 Emington 1 pilot study 4.5 880 370 700 190 273 est. 5.38 est. 1 Defined as the point where postdevice fluoride concentration reached the local MCL. 2Capital, amortized 10% for 20 years + maintenance. Table 5. Emington, Illinois, POU Reverse Osmosis Study Participating Sites Service Area Type Mean Treated Water Use (gpd) Mean Flow Rates (gpd) Product Water Reject Water Fluoride (mean mg/L) Predevice Postdevice Total Dissolved Solids (mean mg/L) Predevice Postdevice POU Treatment Costs Capital ($)1 To Customer ($/month)2 Estimated Central Treatment Costs Capital ($) To Customer ($/month)2 47 central system with single family homes 0.8 2.9 22.5 4.5 0.6 2530 520 540 12.48 122,000 28.80 1 Average of six manufacturers; includes equipment + installation costs. 2Capital, amortized at 10% for 20 years + maintenance. ------- samples were negative for coliform or- ganisms. No conforms were detected in postdevice samples collected in Rock- away. Bacteriological samples collected at AA POU sites indicated microbial colo- nization of the alumina bed, though not as great as with activated carbon. At the Arizona sites, slight increases in SPCs through AA devices Were observed. Flushing reduced SPCs by a small mar- gin. No coliforms were detected in Ari- zona AA postdevice samples. In Bureau Junction, postdevice SPCs were highest when devices were first placed in opera- tion, and decreased with use. There was no evidence of colonization of AA devices by coliform organisms. Out of 153 samples, coliforms were detected in 9 predevice samples and 4 postdevice samples. One unit maintained consis- tent positive coliform results and was removed from service. Resamples from other units were negative for coliforms. In Parkersburg, postdevice SPCs were highest when no influent chlorine resid- ual was detected. Flushing and disin- fecting taps reduced postdevice SPCs by an order of magnitude. No coliforms were detected in 80 Parkersburg post- device samples. SPC results from Emington (RO & AC) demonstrated an order of magnitude in- crease through the treatment system. Limited sampling from stages in the RO & AC system indicated that most bacte- rial growth was occurring in the AC pol- isher. Of 92 samples, coliforms were de- tected in 4 predevice and 11 postdevice samples. One site was resampled twice before postdevice samples were clear, and another site required disinfection of the RO system twice before resamples were acceptable. Resamples from other units were acceptable. Summary and Conclusions Both central and POU AA treatment are effective in reducing fluoride levels in otherwise potable water. POU treat- ment with AA appears to be cost com- petitive with central treatment for com- munities having 330 to 710 service connections. Raw water quality (i.e., al- kalinity) and water comsumption deter- mine the operational life of the POU AA device and have significant impact on costs. Low-pressure POU RO treatment was effective in reducing fluoride and total dissolved solids from a brackish groundwater supply. POU AC treatment devices effectively reduced concentra- tions of trichloroethylene, tetra- chloroethylene, carbon tetrachloride, 1,1,1-trichloroethane, 1,1-dichloro- ethylene, 1,1-dichloroethane, and chlo- roform at influent concentrations studied. Monitoring is required to ensure con- sistent performance on a community level. For AA devices, monitoring may be accomplished with field tests. For VOC reduction in most cases, it is more cost effective to replace AC cartridges prematurely than to pay for frequent analysis. For this method to be effective, relatively consistent source water qual- ity is required. Microorganisms, measured by the standard plate count method, were present in higher numbers in post- device water than in predevice water. Variation of sampling techniques for collecting bacteriological samples from POU devices significantly affected re- sults. Flushing taps can significantly im- prove bacteriological quality. The oc- currence of coliforms in postdevice samples appeared to be associated with the bacteriological quality of the source water. Recommendations A sound program for management of POU treatment systems is necessary to ensure that the desired level of treat- ment is provided to all sites, that pre- scribed monitoring and maintenance are carried out, and that the system is in compliance with applicable regulations. This may be accomplished through for- mation of a water quality district, an in- dependent corporate body. The district obtains funding, incurs costs, and as- sumes responsibility for the treatment system. The district may resemble ex- isting districts created for water supply, wastewater discharge, or solid waste disposal. For POU treatment to be con- sidered as a means of compliance with regulations, regulatory agencies may require the establishment of a clearly defined body to assume responsibility for the system. Formation of an offi- cially sanctioned district may also open avenues for funding not otherwise available. The basic management func- tions of a water quality district include determination of the best treatment ap- proach, equipment selection, coordina- tion of equipment installation, monitor- ing and maintenance, district admin- istration, and education and public noti- fication. The full reports were submitted in partial fulfillment of Cooperative Agree- ment R809248 by the National Sanita- tion Foundation under the sponsorship of the U.S. Environmental Protection Agency. U. S. GOVERNMENT PRINTING OFFICE: 1986/646-116/20762 ------- Gordon E. Bellen, Marc Anderson, and Randy A. Cottier are with the National Sanitation Foundation, Ann Arbor, Ml 48106. Steven Hathaway is the EPA Project Officer (see below). This Project Summary covers three separate reports, entitled: "Point-of-Use Reduction of Volatile Halogenated Organics in Drinking Water,"(Order No. PB 86-107 711/AS; Cost: $11.95) "Defluoridation of Drinking Water in Small Communities," (Order No. PB 86-109 337/AS; Cost: $16.95) "Management of Point-of-Use Drinking Water Treatment Systems." (Order No. PB 86-105 285/AS; Cost: $11.95) The above reports will be available only from: (cost subject to change) National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Water Engineering Research Laboratory U.S. Environmental Protection Agency Cincinnati, OH 45268 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati OH 45268 Official Business Penalty for Private Use $300 EPA/600/S2-85/112 0000329 PS U S ENVIR PROTECTION AGENCY REGION 5 LI8R*RY 230 S DEARBORN STREET CHICAGO It 60604 ------- |