AWWA ACE61776

The Long Beach Water Department (LBWD) is conducting comprehensive research to evaluate seawater desalination integration issues. Although distribution system corrosion has historically been the main concern with integrating desalinated seawater, recent research has identified a detrimental phenomenon associated with rapid loss in disinfectant residual when chloraminating desalinated seawater. This residual instability not only reduces the system's ability to suppress microbial activity, it also raises concerns with nitrification. In addition, the need to rechlorinate to recover the residual loss can impact disinfection byproduct (DBP) formation, as presence of higher bromide coupled with natural organic matter in the system may result in substantial formation of DBPs. Extensive bench top evaluations were performed using various synthetic waters and end-quality desalinated seawaters to understand the behavior of chloramination of waters containing bromide and to quantify extent of the residual stability impacts. The results of these investigations are discussed in this paper. Includes 11 references, table, figures.