RECLAIMED WATER and the uncertainties

NRC 1998,"reclaimed waste water can be used to supplement drinking-water sources, but only as a last
resort and after a thorough health and safety evaluation."

This is a follow up to the 1996 NRC study - (National Academy of Science)  USE OF RECLAIMED WATER & SLUDGE
ON FOOD CROPS --Review.  Based on the report, it was only a matter of time before bacterial food and water
poisoning incidents exploded!

Committee to Evaluate the Viability of Augmenting                             
Potable Water Supplies with Reclaimed  Water  
Microbial Contaminants in Reuse Systems

                                                                                                           Health-effect studies excerpts
Read Full Report
Date: March 11, 1998
Contacts: Ellen Bailey Pippenger, Media Relations Associate
Dumi Ndlovu, Media Relations Assistant
(202) 334-2138; e-mail <>


Publication Announcement

Reclaimed Waste Water Can Augment Municipal Drinking-Water Supplies
But Uncertainties Must Be Addressed

The demand for drinking water in cities and the lack of new water sources have spurred water conservation and
recycling measures over the last 30 years. Need, coupled with advances in water treatment technology, is motivating
a small but growing number of cities to use reclaimed waste water to supplement drinking-water supplies. But,
important questions remain regarding the level of treatment, monitoring, and testing needed to ensure public safety.

In its new report,
Issues in Potable Water Reuse, a National Research Council committee concluded that reclaimed
waste water can be used to supplement drinking-water sources, but only as a last resort and after a thorough health
and safety evaluation. Municipalities first must fully assess health impacts from likely contaminants and develop
comprehensive systems for monitoring, testing, and treatment. Other water sources and conservation measures also
should be tried to the extent practical, before turning to reclaimed waste water.

Because regulations for safe drinking water were not developed with reclaimed water in mind, they may not be the
best standard for testing its quality, the committee said. Reclaimed water may contain sources of contamination that
cannot be determined through current testing or treatment processes.

When considering reclaimed waste water for public water supplies, the report distinguishes between direct and
indirect use. Adding highly treated waste water directly into a water supply without storing it first in a reservoir is not a
viable option. Indirect use is viable, however, and that approach was examined by the committee. Indirect use
augments the drinking-water supply by adding reclaimed treated water first to a lake, reservoir, or underground
aquifer. The mixture of natural and reclaimed water is then subjected to normal water treatment before it is distributed
as drinking water for the community. Since the 1960s, California's Los Angeles County has operated an indirect-use
system in which waste water, mixed with storm water and river waters, supplies about 16 percent of total flow into
ground-water basins. This mixture then is used as a source for drinking-water supplies.

The committee reviewed other reclaimed-water projects currently operating in the United States, including those
supplying Northern Virginia, Orange County, Calif., and Phoenix. It also examined feasibility studies conducted by the
cities of San Diego and Tampa. Limited data from projects and studies nationwide show that highly treated reclaimed
waste water produced drinking water of excellent quality, and that no obvious health effects have been found in
animal tests or in communities where reclaimed water has been used. These results are insufficient, however, and
more information is needed, the report says.

Given health and safety concerns, the committee identified key priorities for water agencies that add treated waste
water to their systems, or are considering doing so:

> Evaluate the potential health effects from possible contaminants. All major sources of household, industrial, and
agricultural chemical contaminants in reclaimed water should be documented and removed based on existing federal
clean-water standards. Since it is unclear whether or not highly treated waste water contains harmful levels of
byproducts from disinfection processes such as chlorination, this issue should be addressed by the research
community. The Environmental Protection Agency should sponsor a study to develop methods for better detection of
new pathogens. Most outbreaks of waterborne disease in the United States are caused by parasites and viruses, yet
few drinking-water systems monitor for the full range of such pathogens.

> Assess the health risks of drinking reclaimed water. After reviewing the few studies that have examined the health
implications of drinking reclaimed water, the committee said that different approaches are needed to test the safety of
reclaimed water. Conventional toxicology tests developed by the food and drug industries are not appropriate for
evaluating the risks from complex chemical mixtures that can be found in reclaimed water. Alternative studies, such as
tests using fish in source water, should be undertaken to provide a broader range of data about possible harmful
effects to living organisms. Research also is needed on the level of viruses and parasites in all waters and the
effectiveness of both conventional and advanced water treatment processes in removing these pathogens. The
federal government should undertake population studies that compare the disease rates over time among individuals
exposed to reclaimed water to the disease rates among individuals who use a different water source.

> Monitor the reliability and operation of water treatment systems. There are two essential keys to the safe, reliable
operation of a reclaimed-water treatment system: good design that provides redundant safety measures to prevent
contamination, and monitoring systems that detect variations in water quality and system performance. Other
measures should be implemented as well. Since waterborne viruses, bacteria, and parasites pose the greatest threat
to public safety, water treatment procedures for removing them should necessarily be the most stringent.
Communities using reclaimed water should implement well-coordinated, public health surveillance systems to
document and provide early warning of any adverse health effects associated with the ingestion of reclaimed water.

The study was funded by the American Waterworks Association Research Foundation, the County Sanitation Districts
of Los Angeles County, the Phoenix Water Services Department, the U.S. Bureau of Reclamation, the Environmental
Protection Agency, the Water Environment Research Foundation, and the National Water Research Institute. The
National Research Council is the principal operating arm of the National Academy of Sciences and the National
Academy of Engineering. It is a private, non-profit institution that provides science advice under a congressional
charter. A committee roster follows.

Read the full text of Issues in Potable Reuse:
The Viability of Augmenting Drinking-Water Supplies with Reclaimed
Waterfor free on the Web, as well as more than 1,800 other publications from the National Academies. Printed copies
are available for purchase from the
National Academy Press Web siteor at the mailing address in the letterhead; tel.
(202) 334-3313 or 1-800-624-6242. Reporters may obtain a pre-publication copy from the Office of News and Public
Information at the letterhead address (contacts listed above).


Commission on Geosciences, Environment, and Resources
Water Science and Technology Board

Committee to Evaluate the Viability of Augmenting
Potable Water Supplies with Reclaimed Water

James Crook (chair beginning August 1996)
Director of Water Reuse
Black and Veatch

Richard S. Engelbrecht (* †)(chair until August 1996)
Professor of Environmental Engineering
University of Illinois

Mark M. Benjamin
Professor of Engineering
Department of Civil Engineering
University of Washington

Richard J. Bull
Senior Research Scientist
Molecular Biosciences Resource
Pacific Northwest National Laboratory
Richland, Wash.

Bruce A. Fowler
Office of Collaborative Studies, Adaptive Responses, and Estuarine Species
University of Maryland

Herschel E. Griffin
Professor Emeritus of Epidemiology
Graduate School of Public Health
San Diego State University
San Diego

Charles N. Haas
Betz Chair Professor of Environmental Engineering
Department of Civil and Architectural Engineering
Environmental Studies Institute
Drexel University

Christine L. Moe
Assistant Professor
Department of Epidemiology
University of North Carolina
Chapel Hill

Joan B. Rose
Marine Science Department
University of South Florida
St. Petersburg

R. Rhodes Trussell (*)
Senior Vice President for Corporate Development
Montgomery Watson Inc.
Pasadena, Calif.


Jacqueline A. MacDonald
Study Director (beginning July 1997)

Gary D. Krauss
Study Director (until July 1997)

(*) Member, National Academy of Engineering