Case Study

East Bay Municipal Utility District Successfully Manages Chloramine Residual In Ten Million Gallon Reservoir With The Process Solutions, Inc. Monoclor® RCS Chloramine Management System


Located on the eastern side of the San Francisco Bay, the East Bay Municipal Utility District (EBMUD) treats and distributes water to over 1.3 million customers in Alameda and Contra Costa counties. As one of the largest utility districts in California, EBMUD is a leader in the water industry’s water quality, conservation and sustainability efforts.

EBMUD chloraminates water prior to distribution and uses chloramines for secondary disinfection in order to mitigate DBP (disinfection byproduct) formation. Chloramine, formed by reacting aqueous chlorine with ammonia, is a more stable disinfectant in distribution systems, but maintaining residual set‐points can be challenging for many utilities due to the complexities of chloramine chemistry in a distribution system. Once chloramine dosed water leaves a treatment plant, monochloramine degrades in distributions systems and free ammonia is released. Free ammonia is utilized by ammonia oxidizing bacteria which convert the ammonia into nitrites and nitrates further accelerating the monochloramine decay process. Additionally, the ongoing drought complicates water quality management for EBMUD and exacerbates residual and temperature stratification, nitrification, and taste and odor issues. All of these factors create the potential for the loss of increasingly precious quantities of stored water.