AWWA JAW58673

N-Nitrosodimethylamine (NDMA) is a new disinfection byproduct (DBP) issue, and a particularly important one, because it affects chloramination, one of the principle means water utilities have for addressing other DBPs. This article shows how cationic polymers, widely used for coagulation, are also a source of trace levels of NDMA, which is formed when water treated with the polymer is chloraminated. The authors undertook this study because of elevated and variable levels of NDMA measured in a large distribution system. No previous similar cases were reported, and a comprehensive study was conducted to determine the sources of NDMA. This is a new field of investigations and will likely result in more studies and eventually the establishment of guidelines for application of organic polymers in drinking water. Water utilities can use the information in this article to minimize NDMA formation in chloraminated water systems that use cationic organic polymers to aid coagulation. The findings may also lead to more stringent treatment of filter backwash recycle streams. Includes 24 references, tables, figures.