Investigating the presence of HAAs and THMs in sodium hypochlorite feedstocks


Chlorate ion and perchlorate ion are examples of disinfection by-products (DBPs) that form in situ in sodium hypochlorite (NaOCl) feedstocks, not in the distribution system. Much less is known about the presence of organic DBPs, such as haloacetic acids (HAAs) and trihalomethanes (THMs) in NaOCl feedstocks. In a preliminary survey, the concentrations of trihalomethanes and haloacetic acids were measured in sodium hypochlorite feedstocks collected from five different utilities from the Southern and Midwestern United States. Significant concentrations of three of the five regulated haloacetic acids were quantified in four out of five of the utilities surveyed. Trihalomethanes were also detected in much lower concentrations. These species may be formed during the production process, during storage, during application or in a combination of all these times. Based on our limited survey, it appears that NaOCl feedstocks may be a significant source of three HAA species in finished water for utilities that use hypochlorite ion feedstocks. 2011 © American Water Works Association AWWA WQTC Conference Proceedings All Rights Reserved.

Publication Title

Water Quality Technology Conference and Exposition 2011

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