Effluents from wastewater treatment plants (WWTPs) contain disinfection byproducts (DBPs) of health concern when the water is utilized downstream as a potable water supply. The pattern of DBP formation was strongly affected by whether or not the WWTP achieved good nitrification. Chlorine addition to poorly nitrified effluents formed low levels of halogenated DBPs, except for (in some cases) dihalogenated acetic acids, but often substantial amounts of N-nitrosodimethyamine (NDMA). Chlorination of well-nitrified effluent typically resulted in substantial formation of halogenated DBPs but much less NDMA. For example, on a median basis after chlorine addition, the well-nitrified effluents had 57 μg/L of trihalomethanes [THMs] and 3 ng/L of NDMA, while the poorly nitrified effluents had 2 μg/L of THMs and 11 ng/L of NDMA. DBPs with amino acid precursors (haloacetonitriles, haloacetaldehydes) formed at substantial levels after chlorination of well-nitrified effluent. The formation of halogenated DBPs but not that of NDMA correlated with the formation of THMs in WWTP effluents disinfected with free chlorine. However, THM formation did not correlate with the formation of other DBPs in effluents disinfected with chloramines. Because of the relatively high levels of bromide in treated wastewater, bromine incorporation was observed in various classes of DBPs. © 2009 American Chemical Society.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors thank the Awwa Research Foundation and the U.S. Environmental Protection Agency (USEPA) for its financial, technical, and administrative assistance in funding and managing the project through which this information was discovered. The project manager was Alice Fulmer. The authors also acknowledge Zaid K. Chowdhury and Shahnawaz Sinha of Malcolm Pirnie, Inc. for setting up portions of the full-scale sampling survey. Thanks are given to the Metropolitan staff that conducted various analyses in support of this study. Finally, the participating utilities are acknowledged for their invaluable assistance and support.
ASJC Scopus subject areas
- Environmental Chemistry