Catolico

Journal of Toxicology and Environmental Health, Part A, 71: 1133–1148, 2008
Copyright © Taylor & Francis Group, LLC
ISSN: 1528-7394 print / 1087-2620 online
DOI: 10.1080/15287390802182060

Integrated Disinfection By-Products Mixtures Research:
Disinfection of Drinking Waters by Chlorination and
Ozonation/Postchlorination Treatment Scenarios
UTEH

Richard J. Miltner1, Thomas F. Speth1,Susan D. Richardson2,
Stuart W. Krasner3, Howard S. Weinberg4, and Jane Ellen Simmons5
Preparation Of Disinfected Drinking Water

1

National Risk Management Research Laboratory, Office of Research and Development, U.S.
Environmental Protection Agency, Cincinnati, Ohio, 2National Exposure Research Laboratory,
Office of Research and Development, U.S. Environmental Protection Agency, Athens,Georgia,
3
Metropolitan Water District of Southern California, La Verne, California, 4Department of
Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina, and
5
National Health and Environmental Effects Research Laboratory, Office of Research and Development,
U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA

Thisarticle describes disinfection of the same source water by two
commonly used disinfection treatment scenarios for purposes of
subsequent concentration, chemical analysis, and toxicological
evaluation. Accompanying articles in this issue of the Journal of
Toxicology and Environmental Health describe concentration of these
finished waters by reverse osmosis techniques, chemical characterizationof the resulting disinfection by-product (DBP) concentrates,
in vivo and in vitro toxicological results, and risk assessment methods
developed to analyze data from this project. This project, called the
“Four Lab Study,” involved participation of scientists from four laboratories/centers of the U.S. Environmental Protection Agency Office
of Research and Development as well as extramuralcollaborators
from the water industry and academia. One of the two finished
waters was prepared by conventional treatment and disinfected by
chlorination. The other finished water was also prepared by conventional treatment and disinfected by ozonation followed by chlorination (ozonation/postchlorination). Chlorination conditions of dose,
time and temperature were similar for both treatmentscenarios,
allowing for a comparison. Both finished waters had acceptably low
levels of particulates and bacteria, representative pH and chlorine
levels, and contained numerous DBP. Known effects of ozonation
were observed in that, relative to the water that was chlorinated only,
the ozonated/postchlorinated water had lower concentrations of total
organic halogen, trihalomethanes (THM), haloaceticacids (HAA),
and higher concentrations of bromate, and aldehydes.

This article has been reviewed by the U.S. Environmental
Protection Agency and approved for publication. Approval does not
signify that the contents necessarily reflect the views and policies of
the agency, nor does mention of trade names constitute endorsement
or recommendation for use.
Address correspondence to Richard J.Miltner, U.S. EPA, 26 W.
M.L. King Jr. Dr., Cincinnati, OH, 45268. Email: miltner.richard@
epa.gov

The purpose of disinfection of water is control of microbes
and the prevention of outbreaks of waterborne disease. Complex mixtures of disinfection by-products (DBP) are formed
in drinking waters when chlorine or other oxidants (principally ozone, chloramines, or chlorine dioxide) are used asdisinfectants. The oxidants react with natural organic matter
(NOM) in source waters. Bromide, the principal halide in
source waters, also reacts, resulting in bromo-DBP. Many
factors affect DBP formation including pH, temperature, oxidant concentration, NOM concentration, the nature of the
NOM, halide concentration, and time. Hundreds of DBP were
identified in finished drinking waters;...