AWWA WQTC58851

This paper discusses how a utility and its bulk supplier have been working cooperatively on a pilot study of entry point chloramination to quench the formation of additional disinfection byproducts in the distribution system. The bulk supplier constructed chloramination facilities at the entry point and has been operating these facilities since June 2002. The utility and its bulk supplier have been monitoring relevant entry point and distribution system water quality parameters quarterly or monthly since 1998. The monitoring data illustrate the temporal and spatial extent of disinfection byproduct control achieved through entry point chloramination. The costs to construct and operate the pilot facilities provide benchmarks for other utilities facing a similar challenge. Chloramination of the entry point appears to have reduced the formation of additional disinfection byproducts significantly. Chloramination also appears to have other water quality benefits in the distribution system. The effort, financial and otherwise, needed to implement entry point treatment is one that utilities should consider only after implementing other strategies to minimize the formation of disinfection byproducts. Other systems with variable bulk water quality, competing water quality objectives, extensive reliance on unlined cast iron pipe, poorly configured pipe networks and limited funds may benefit from the experiences of this system. Benefiting systems include those considering boosting residuals in their distribution systems, as well as other consecutive systems. Includes 4 references, figures.