Treatment of Water by Granular Activated Carbon - ACS Publications

1 Overview: Role of Activated Carbon in EPA's Regulatory Program JOSEPH A. C O T R U V O , H U G H F. HANSON, and THOMAS P. T H O R N T O N

Downloaded by 80.82.77.83 on May 18, 2017 | http://pubs.acs.org Publication Date: March 15, 1983 | doi: 10.1021/ba-1983-0202.ch001

Environmental Protection Agency, Washington, D.C. 20460

Past EPA actions affecting the water utility industry and the basis for EPA regulatory actions are reviewed. Ongoing regulatory efforts of the Office of Drinking Water are focusing on implementation of the trihalomethane regulations, development of an Advance Notice of Proposed Rulemaking for volatile organic chemicals, and National Revised Primary Drinking Water Regulations. Current research needs of the EPA, including a call for participation in the EPA Competitive Grants Program, are outlined.

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OTH PAST AND FUTURE EPA ACTIONS may influence the use of granular

activated carbon (GAC) as a potable water treatment technology. Past EPA actions affecting the water utility industry include the promulgation of the National Interim Primary Drinking Water Regulations (NIPDWR) (1), the simultaneous proposals to control both trihalomethanes (THMs) and synthetic organic chemicals (SOCs) in drinking water (2), and the subsequent promulgation of the T H M regulations (3) and the subsequent withdrawal of the proposal on SOCs. Present and future Office of Drinking Water (ODW) actions impacting the water supply industry include the implementation of the T H M regulations and the development of the comprehensive National Revised Primary Drinking Water Regulations (NRPDWR). The first phase of this latter activity may be the publication of regulations for certain synthetic volatile organic chemicals (VOCs) commonly found in groundwater supplies.

Basis for EPA Regulatory Actions EPA's O D W operates under the authority of the Safe Drinking Water Act (SDWA) (4), which is quite explicit in its intent to protect the public health to the maximum extent possible. Thus, the EPA Administrator is empowered to take action concerning any substance in drinking water 0065-2393/83/0202-0001/$06.00/0 © 1983 American Chemical Society

McGuire and Suffet; Treatment of Water by Granular Activated Carbon Advances in Chemistry; American Chemical Society: Washington, DC, 1983.


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TREATMENT OF WATER BY GRANULAR ACTIVATED CARBON

which he determines may have an adverse effect on human health. Such actions, however, must take into account both technical feasibility and cost. EPA has initiated five major national monitoring surveys to gain perspective on the frequency and intensity of the organic chemical pollution reaching U.S. citizens through their drinking water. These surveys have focused on different sources of water, different segments of the population, and different contaminants of concern. The results of four surveys [National Organics Reconnaissance Survey (NORS), National Organic Monitoring Survey (NOMS), National Screening Program for Organics in Drinking Water (NSP), and Community Water Supply Survey (CWSS)] form the basis of EPA's current knowledge about the occurrence of organics in the nations drinking water. Data from the fifth survey, the National Rural Water Survey (NRWS), are now becoming available. In addition, EPA has initiated another national survey that will further assess the contamination of groundwater sources by VOCs. The Ground Water Supply Survey (GWSS) is a joint venture between EPA and the individual states. Specific segments of this study are geared toward developing a method of predicting the location of potential contamination sites and improving the federal/state response to incidents of contamination. It is hoped that this new study will markedly increase the level of knowledge on the nationwide occurrence and intensity of groundwater contamination. The results of the GWSS should be particularly interesting in light of the changing perceptions of groundwater quality which the previous studies have fostered. Previous studies detected the presence of a wide range of synthetic organic chemicals in finished drinking waters. Historically, groundwater had been viewed as a relatively uncontaminated resource, unspoiled by the human activities that affect surface waters. Traditional attention of public health officials was focused on those surface waters subject to wastewater discharges, industrial discharges, and nonpoint source run-off. However, data from the described studies are beginning to indicate that, while many surface waters are subject to contamination by a broad spectrum of SOCs at relatively low (microgram per liter) levels, a small percentage of groundwater supplies also are contaminated by one or more discrete compounds, sometimes at much higher concentrations (i.e., 1001000 /xg/L) than have been experienced in surface water. While the data from these surveys may not be representative of the total national picture, significant contamination has been found to occur in numerous locations. Finding even trace quantities of synthetic organics in drinking water supplies should be a cause of concern since this is a direct indication that a mechanism exists for contamination of that supply by man-made pollutants. To date, the various surveys have detected the presence of more than 1000 individual chemicals in some drinking waters. Concern over the


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COTRUVO ET AL.

Activated Carbon and EPA's Regulatory Program

presence of these chemicals arises from the potential human health risks exposure to these chemicals may introduce. Many are suspected carcinogens, while, in some test systems, certain of these chemicals have been shown to be either mutagenic or teratogenic. Vinyl chloride, for example, is a known human carcinogen and has been found in some public water supplies. Also, chloroform has been identified as an animal carcinogen by the National Academy of Sciences (5).


Current Regulatory Efforts Given these facts and concerns, the ongoing regulatory activities of O D W are focused in the following areas: • •

Implementation of the trihalomethane regulations Development of an Advance Notice of Proposed Rulemaking for volatile organic chemicals • National Revised Primary Drinking Water Regulations

The T H M regulations were published in the Federal Register on November 29, 1979. Those regulations set an enforceable Maximum Contaminant Level (MCL) of 0.10 mg/L for total THMs in drinking water and imposed various monitoring/reporting requirements on affected systems. The effective dates of the individual segments of these regulations vary according to system size, with monitoring requirements for only the largest systems (those serving greater than 75,000 persons) having become effective to date. However, the remaining segments of these regulations (covering systems serving 10,000-75,000 persons) will become effective soon. To comply with this M C L , it is anticipated that only a small number of affected systems throughout the country will choose to install either granular- or powdered-activated carbon. Such installations will either remove T H M precursors from source waters or remove the actual THMs after their formation. The other half of the original joint proposal, the use of GAC as a required treatment for SOC contaminated systems, was not finalized. The GAC proposal was withdrawn by Federal Register Notice in March 1981. The proposal envisioned GAC as a comprehensive treatment technique for removing contaminants from those surface water supplies considered to be vulnerable to SOC pollution. Comments received on that proposal, as well as new data made available from EPA-sponsored research projects, caused O D W to reconsider the G A C proposal and eventually to withdraw it.


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O D W is presently re-evaluating that original proposal based upon concerns over the definition of a vulnerable water system, the performance levels, regeneration frequencies and costs of GAC, and the specific criteria for alternate treatment techniques. Future O D W actions will emphasize MCLs for individual chemicals or groups of chemicals rather than a general treatment technique requirement. O D W s more immediate focus is on the development of the National Revised Primary Drinking Water Regulations (NRPDWR) that are intended by law to "contain a comprehensive program of control of drinking water contamination" (6). These regulations are intended to provide a set of enforceable standards that will assure the healthfulness of the drinking water provided at the taps of American consumers. These regulations are intended to be an evolution of the already promulgated NIPDWR. The first phase of the NRPDWR is anticipated to be the determination of whether MCLs are needed for VOCs such as trichloroethylene and carbon tetrachloride. An Advance Notice of Proposed Rulemaking (ANPRM) on this subject is being developed for Federal Register publication. The alleviation and/or prevention of groundwater contamination problems is currently capturing much of EPA's attention, as evidenced by the Underground Injection Control (UIC) regulations, the Resource Conservation and Recovery Act (RCRA) regulations, the Ground Water Strategy Initiative, and the ongoing Superfund activities. Since the chief drinking water related contamination problems appear to involve VOCs in groundwater-supplied systems, O D W s concentration on possible regulatory action for those VOCs is largely consistent with EPA's current outlook. Current data suggest that aeration and/or G A C will provide effective controls in many cases of VOC-contaminated groundwater. Adsorption of organics by synthetic macroreticular resins also is a promising treatment technique. Given the nature of the VOC contamination problem, package plants or even home treatment devices in very small communities also might be an appropriate removal method.

Current Research Needs In addition to many ongoing in-house research projects, EPA is currently supporting several pilot and field scale projects to evaluate the feasibility of and obtain operating and cost data for GAC. These field projects are located in: New Orleans, Shreveport, and Jefferson Parish, La.; Passaic Valley, N.J.; Philadelphia, Pa.; Kansas City, Mo.; Miami, Fla., Cincinnati, Ohio; Glen Cove, N.Y.; Manchester, N.H.; and Evansville, Ind.



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Activated Carbon and EPA's Regulatory Program

O D W s Technical Support Division (TSD) is currently conducting a survey of existing G A C water treatment plant units (used mostly for control of tastes and odors) to determine their applicability for removing a broad spectrum of organics from source waters. This study will specifically attempt to determine the reasonable service life to be expected from such a filter. Limited data indicate that GAC, when utilized in the sandreplacement mode at an existing conventional water treatment plant, can be useful in removing certain SOCs. Also, O D W recently funded a project at the University of North Carolina which will attempt to develop an analytical technique that can identify and quantify the individual chemicals adsorbed by GAC filters during long periods of usage. These are two areas where O D W s current knowledge concerning GAC is not extensive. O D W needs advice on exactly what role the activated-carbon technology can play in EPA's comprehensive approach to implementing the SDWA. Ideally, those aspects of activated-carbon treatment that require additional explanation or further research will be identified. Relevant technical information should be provided to assist O D W in evaluating the performance and practicality of G A C in potable water treatment Finally, O D W encourages participation in EPA's Competitive Grants Program in those areas for which they have interest This program is a relatively new mechanism for funding long-range research activities which support ongoing EPA regulatory efforts. Through this competitive process, EPA hopes to increase the number of proposals available for consideration, stimulate greater competition among proposal writers, and improve the quality of any research grants eventually funded. Many significant aspects of GAC treatment technology would seemingly be eligible for such funding. Qualified individuals or organizations that desire to conduct research into areas of concern to EPA are encouraged to submit formal proposals to the appropriate EPA research office. All grant applications will be reviewed by the appropriate Science Peer Review Panel, composed primarily of non-EPA scientists. That review will evaluate the scientific merit of each proposal, rank each according to its merit, and result in a recommendation to EPA.

Conclusion O D W currently perceives that G A C will become an increasingly important weapon in the fight to protect the quality of drinking water. GAC, when employed with other unit treatment operations, has demonstrated a capability for groundwater contaminant removal. However, questions remain regarding this technology's drinking water applications, e.g., frequency of required regeneration and chromatographic effects.


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Literature Cited 1. National Interim Primary Drinking Water Regulations, U.S. EPA-570/9-76003, Office of Water Supply, December 24, 1975. 2. Federal Register, February 9, 1978, pp. 5756-5780. 3. Federal Register, November 29, 1979, pp. 68,624-68,707. 4. The Safe Drinking Water Act, as amended (42 U.S.C., §300 fet.seq.). 5. "Drinking Water and Health," National Academy of Sciences: Washington, D.C., June 1977; p 6-256. 6. The Safe Drinking Water Act (42 U.S.C., §1401).


RECEIVED for review August 3, 1981. ACCEPTED for publication March 4, 1981.


Treatment of Water by Granular Activated Carbon - ACS Publications

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