Management of hypochlorite solutions used for water treatment in small drinking water systems

Abstract

Hypochlorite solutions (HSs), also called liquid chlorine, are widely used as disinfectants during drinking water treatment and distribution. However, the decomposition of the hypochlorite ion results in the formation of undesirable inorganic contaminants such as chlorite, chlorate, bromate and perchlorate. While HS decomposition cannot be completely avoided, it can be minimized through applying adequate practices during the purchasing, handling and storage of such solutions. This article presents the results of an investigation of the management of HS in water treatment plants (WTPs) in small municipalities. The data concerning HS management were acquired through field visits and semi-structured interviews with operators and managers of the small WTPs. The information gathered about HS management practices was compared to best management practice guidelines. Results show that practices involving HS differ between WTPs and that there are important gaps in the application of the existing HS management guidelines. The research revealed that the implementation of specific guidelines for the purchasing, handling and storage of HS is difficult for small WTPs due to the lack of human resources, expertise, and education, as well as a lack of infrastructure capacity.