Most drinking water treatment plants that treat surface waters use enhanced coagulationor enhanced softening to remove precursors for trihalomethanes (THMs) and haloacetic acids(HAAs). In addition, many plants use ozone and chloramines to minimize the formation of theregulated organic disinfection byproducts (DBPs). Although there is no federal standard for N-Nitrosodimethylamine(NDMA), California has a notification level of 10 ng/L and a public health goal of 3 ng/Lfor NDMA. Moreover, NDMA is in the U.S. Environmental Protection Agency's (USEPA's)Unregulated Contaminant Monitoring Rule 2 and is on the Contaminant Candidate List 3. Thus, there is concern over the source of NDMA precursors in drinking water supplies, aswell as treatment/disinfection practices to control NDMA formation. This paper addresses thesource of NDMA precursors in the source waters treated by Metropolitan Water District ofSouthern California (MWDSC) and how various treatment processes at MWDSC's plants impactNDMA precursors. Includes 12 references, tables, figures.
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Edition: Vol. - No. Published: 11/01/2008 Number of Pages: 39File Size: 1 file , 890 KB