National Academy Press
2101 Constitution Avenue, NW Washington, DC20418
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competencies and with regard for appropriate balance.
Support for this project was provided by the American Water Works Association Research Foundation, County Sanitation Districts of Los Angeles County, National Water Research Institute, Phoenix Water Services Department, San Diego County Water Authority, U.S. Bureau of Reclamation under grant nos. 1425-6-FG-81-07010 and 1425-6-FG-3000740, U.S. Environmental Protection Agency under cooperative agreement no. CX 82434001-0, and Water Environment Research Foundation.
Library of Congress Cataloging-in-Publication Data
Issues in potable reuse: the viability of augmenting drinking water supplies with reclaimed water / Committee to Evaluate the Viability of Augmenting Potable Water Supplies With Reclaimed Water, Water Science and Technology Board, Commission on Geosciences, Environment, and Resources, National Research Council.
Includes bibliographical references and index.
1. Water reuse. 2. Drinking water. I. National Research Council (U.S.). Committee to Evaluate the Viability of Augmenting Potable Water Supplies with Reclaimed Water.
TD429 .184 199 98-19686
Issues in Potable Reuse: The Viability of Augmenting Drinking Water Supplies With Reclaimed Water is available from the
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Cover art by Y. David Chung. Chung is a graduate of the Corcoran School of Art in Washington, D.C. He has exhibited his work throughout the country, including at the Whitney Museum in New York, the Washington Project for the Arts in Washington, D.C., and the Williams College Museum of Art in Williamstown, Massachusetts.
Copyright 1998 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America
COMMITTEE TO EVALUATE THE VIABILITY OF AUGMENTING POTABLE WATER SUPPLIES WITH RECLAIMED WATER
JAMES CROOK, Chair,
Black and Veatch, Boston, Massachusetts (from August 1996)
RICHARD S. ENGELBRECHT, Chair,
University of Illinois, Urbana Champaign (through August 1996)
MARK M. BENJAMIN,
University of Washington, Seattle
RICHARD J. BULL,
Pacific Northwest National Laboratory, Richland, Washington
BRUCE A. FOWLER,
University of Maryland, Baltimore
HERSCHEL E. GRIFFIN,
San Diego State University, California
CHARLES N. HAAS,
Drexel University, Philadelphia, Pennsylvania
CHRISTINE L. MOE,
University of North Carolina, Chapel Hill
JOAN B. ROSE,
University of South Florida, St. Petersburg
R. RHODES TRUSSELL,
Montgomery Watson, Inc., Pasadena, California
DAVID A. DOBBS,
JACQUELINE A. MACDONALD, Study Director (from July 1997)
GARY D. KRAUSS, Study Director (until July 1997)
ELLEN A. DE GUZMAN, Senior Project Assistant
WATER SCIENCE AND TECHNOLOGY BOARD
HENRY J. VAUX, Jr., Chair,
University of California, Division of Agriculture and Natural Resources, Oakland
CAROL A. JOHNSTON, Vice-Chair,
University of Minnesota, Duluth
JOHN S. BOYER,
University of Delaware, Lewes
The World Bank, Washington, D.C.
University of New Mexico, Albuquerque
University of Minnesota, St. Paul
THOMAS M. HELLMAN,
Bristol-Myers Squibb Company, New York, New York
CHARLES D. D. HOWARD,
Charles Howard and Associates, Ltd., Victoria, British Columbia
WILLIAM A. JURY,
University of California, Riverside
WILLIAM M. LEWIS, JR.,
University of Colorado, Boulder
RICHARD G. LUTHY,
Carnegie Mellon University, Pittsburgh, Pennsylvania
JOHN W. MORRIS,
J. W. Morris, Ltd., Arlington, Virginia
CHARLES R. O'MELIA,
The Johns Hopkins University, Baltimore, Maryland
REBECCA T. PARKIN,
American Public Health Association, Washington, D.C.
FRANK W. SCHWARTZ,
Ohio State University, Columbus
ERIC F. WOOD,
Princeton University, Princeton, New Jersey
STEPHEN D. PARKER, Director
JACQUELINE A. MACDONALD, Associate Director
CHRIS ELFRING, Senior Staff Officer
LAURA J. EHLERS, Staff Officer
JEFFREY W. JACOBS, Staff Officer
M. JEANNE AQUILINO, Administrative Associate
MARK GIBSON, Research Assistant
ANITA A. HALL, Administrative Assistant
ELLEN A. DE GUZMAN, Senior Project Assistant
KIMBERLY A. SWARTZ, Project Assistant
COMMISSION ON GEOSCIENCES, ENVIRONMENT, AND RESOURCES
GEORGE M. HORNBERGER, Chair,
University of Virginia, Charlottesville
PATRICK R. ATKINS,
Aluminum Company of America, Pittsburgh, Pennsylvania
JERRY F. FRANKLIN,
University of Washington, Seattle
B. JOHN GARRICK, PLG,
Inc., Newport Beach, California
THOMAS E. GRAEDEL,
Yale University, New Haven, Connecticut
Progressive Foundation, Washington, D.C.
KAI N. LEE,
Williams College, Williamstown, Massachusetts
JUDITH E. MCDOWELL,
Woods Hole Oceanographic Institution, Massachusetts
RICHARD A. MESERVE,
Covington & Burling, Washington, D.C.
HUGH C. MORRIS,
Canadian Global Change Program, Delta, British Columbia
RAYMOND A. PRICE,
Queen's University at Kingston, Ontario
H. RONALD PULLIAM,
University of Georgia, Athens
THOMAS C. SCHELLING,
University of Maryland, College Park
VICTORIA J. TSCHINKEL,
Landers and Parsons, Tallahassee, Florida
University of Maryland, College Park
MARY LOU ZOBACK,
United States Geological Survey, Menlo Park, California
ROBERT M. HAMILTON, Executive Director
GREGORY H. SYMMES, Assistant Executive Director
JEANETTE SPOON, Administrative and Financial Officer
SANDI S. FITZPATRICK, Administrative Associate
MARQUITA S. SMITH, Administrative Assistant/Technology Analyst
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.
The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. William A. Wulf is president of the National Academy of Engineering.
The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine.
The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. William A. Wulf are chairman and vice chairman, respectively, of the National Research Council.
This book is dedicated to Dr. Richard Engelbrecht, who chaired the Committee to Evaluate the Viability of Augmenting Potable Water Supplies With Reclaimed Water from its inception until September 1, 1996, when he passed away.
Dr. Engelbrecht was a pioneer in environmental pollution control, particularly in issues related to water quality management and microbiological contamination of drinking water. A dedicated educator, he had been a professor of environmental engineering at the University of Illinois since 1954. He was also extremely active in the professional community, both nationally and internationally. Dr. Engelbrecht was elected to the National Academy of Engineering in 1976.
Dr. Engelbrecht found significant time between his teaching and research responsibilities and his professional involvements to volunteer his knowledge and expertise to further the work of the Water Science and Technology Board. A founding member of the board in 1982, Dr. Engelbrecht served on several of its study committees, including the Panel on Water Quality Criteria for Reuse, which in 1982 published the first independent review of potable reuse of reclaimed water. From 1988 until 1990, he chaired a committee that reviewed the U.S. Geological Survey's National Water Quality Assessment Program. He was a member of the Committee on Mexico City's Aquifer from 1992 until 1995 and the Panel on Sustainable Water and Sanitation Services for Megacities in the Developing World from 1995 until 1996.
Dr. Engelbrecht will long be remembered as one of the most influential figures in water quality and public health.
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The National Research Council (NRC) first provided guidance on potable reuse of reclaimed wastewater in the report Quality Criteria for Water Reuse, developed in 1982 to provide input to an experimental program commissioned by Congress to study the wastewater-contaminated Potomac Estuary as a potential new water source for the District of Columbia. That report focused on the scientific questions concerning what quality criteria should be applied if a degraded water supply is to be used as a source of drinking water. At the time, only a few communities in the United States—notably Denver, Colorado; Los Angeles and Orange Counties, California; and Washington, D.C.—were considering water reuse to augment drinking water supplies.
The 1982 report produced a number of findings regarding the application of existing drinking regulations as applied to a reuse situation, the importance of treatment reliability and confirmatory data, and limitations concerning the identification, measurement, and long-term health risks from trace organic chemicals. The panel that wrote the report recommended that in the absence of an absolute, ideal water standard, the ability of a water reclamation facility to produce potable water should be judged—chemically, microbiologically, and toxicologically—in comparison with conventional drinking waters that are presumed to be safe. The panel suggested that all new projects develop an experimental pilot plant facility and recommended comprehensive toxicological testing to evaluate the potential health risks of unidentified trace organic chemicals. The report also "strongly endorse[d] the generally accepted concept that drinking water should be obtained from the best quality source avail-
able" and noted that "U.S. drinking water regulations were not established to judge the suitability of raw water supplies heavily contaminated with municipal and industrial wastewater." The report suggested that planners should consider "the much greater probability that adequately safe [reclaimed] water could be provided for short-term emergencies rather than for long-term use."
Since then, a number of factors have changed the way people think about drinking water and wastewater. The demand for water in some parts of the country is now so great that the best available sources have already been developed to their maximum extent, forcing municipalities to consider ways to creatively and inexpensively augment drinking water supplies. In addition, changes in water and wastewater treatment technologies have occurred since 1982, with advanced technologies such as advanced-oxidation (including ozone), membrane, and biofilm processes seeing increasing use in the United States and Europe. Finally, several public health concerns have surfaced over drinking water in general, and these concerns may affect the use of reclaimed water for drinking purposes. These include the control of Cryptosporidium and other potentially dangerous human pathogens, increased awareness of the potential dangers of disinfection by-products and other unidentified trace organic chemicals, and the problem of biological instability of wastewaters. When degraded water from whatever source is used, such issues complicate the challenge of meeting acceptable quality standards and ensuring that the water maintains its quality during distribution.
Since the 1982 NRC report, studies on the health implications of using reclaimed water for potable purposes have been completed at a number of projects in the United States. Many of the projects have used a comparative approach, testing both reclaimed and conventional drinking water sources. More advanced methods have been developed and tested for identifying organic chemicals and microbiological agents in reclaimed water, and some have involved whole-animal toxicological studies. A series of epidemiological studies was completed in Los Angeles County, where indirect potable reuse through ground water recharge has been practiced since 1962. None of the studies detected significant effects from chemical toxicants or infectious disease agents; all found the quality of highly treated reclaimed water as good as or better than the current drinking water sources for most or all measures of physical, chemical, and microbiological parameters.
However, limitations in methodology and testing have prevented many within the scientific and technical community from issuing absolute statements that planned potable reuse carries no adverse health-effect implications. Opponents of the use of reclaimed water for potable use point out that communities involved in the practice are subject only
to existing drinking water standards that have been developed exclusively for natural sources of water. No national standards exist for the variety of contaminants (many of them poorly characterized) that may be present in potable water derived from treated municipal wastewater. Meanwhile, proponents have argued that the planned reuse situation is no different (and possibly safer because of tighter controls) than that faced by many communities using water supplies that receive significant upstream discharges of wastewater.
In conducting the review presented in this report, the Committee to Evaluate the Viability of Augmenting Potable Water Supplies With Reclaimed Water based its evaluation on published literature and the expertise of committee members and others consulted during this project. The committee used as its starting point the findings and recommendations of the 1982 NRC report. To gather further information, the committee hosted a two-day workshop in Irvine, California, with principal investigators and project managers of several of the potable reuse projects that have conducted analytical and health-effect studies.
I would personally like to thank my colleagues and fellow committee members for their cooperation, hard work, mutual respect, and enthusiasm. I would also like to thank the staff of the NRC's Water Science and Technology Board (WSTB), especially Gary Krauss and Jackie MacDonald, study directors, and Ellen de Guzman, senior project assistant. On behalf of the committee and WSTB, I would like to thank several people who provided important insight and contributed valuable information to the committee. These include Margie Nellor, Robert Baird, and Bill Yanko of the County Sanitation Districts of Los Angeles County; Michael Pereira of the Medical College of Ohio; Bill Lauer of the Denver Water Department; Bob Bastian of the Environmental Protection Agency; Joe Smith of the U.S. Bureau of Reclamation; Michael Wehner of Orange County Water District; and Adam Olivieri of the Western Consortium for Public Health. Finally, I would like to acknowledge the committee's deep appreciation to Richard Engelbrecht, the original chair of this committee, whose spirit and inspiration continued to help direct our efforts.
This report has been reviewed by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the NRC's Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the authors and the NRC in making the published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The content of the review comments and draft manuscripts remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their participation in the review of this report:
Takashi Asano, University of California, Davis
Rebecca Calderon, Environmental Protection Agency
Russell Christman, University of North Carolina, Chapel Hill
Peter Gleick, Pacific Institute
Adel A. Mahmoud, Case Western Reserve University
Perry McCarty, Stanford University
Daniel Okun, University of North Carolina, Chapel Hill
Vernon Snoeyink, University of Illinois, Urbana-Champaign
Robert Spear, University of California, Berkeley
While the individuals listed above provided many constructive comments and suggestions, responsibility for the final content of this report rests solely with the authoring committee and the NRC.
JAMES CROOK, Chair
Committee to Evaluate the Viability of Augmenting
Potable Water Supplies With Reclaimed Water