[Case Study] SAN JOSE WATER, CA Company Solves Chloramine Residual Problem with the Process Solutions Monoclor® RCS Chloramine Management System

Like many water utilities, San Jose Water has had to adapt to the challenges of using chloramines for secondary disinfection to mitigate potential DBP (disinfection byproduct) formation. Chloramine can be a more stable disinfectant in distribution systems and is formed by reacting aqueous chlorine with ammonia. While the optimal laboratory ratio of chlorine to ammonia is 5:1, “real world” water sources that
contain varying levels of ammonia can wreak havoc on residual concentrations.

Getting mix ratios of ammonia and chlorine wrong can not only result in reduced bacterial control in distribution systems but create nitrification or taste and odor problems as well. Storage tanks pose particular problems to operators as out-of-control chloramine residuals can require a utility to flush or dump an entire tank – an increasingly unacceptable outcome in water stressed California. San Jose Water’s Nitrification Monitoring Program identified the need to boost chloramine residuals in some of its tanks. A chloramine boosting pilot in one of San Jose Water’s 1 million gallon storage tanks was unable to correctly dose the tank with either free chlorine or ammonia to achieve the desired target residuals.