Monoclor RCS Chloramine Residual Management System Manages Residual for Problematic 5.5 Million Gallon Tank for Eastern Municipal Water District Case Study

Monoclor®RCS Chloramine Residual Management System Manages Residual for Problematic 5.5 Million Gallon Tank for Eastern Municipal Water DistrictEastern Municipal Water District (EMWD) serves about 142,000 customers in Riverside County, California. The EMWDservice area is one of the largest for any water district in arid southern California. On the drinking water side, EMWD manages two water treatment plants and over 15 reservoirs. With 70% of the district’s water coming from the Metropolitan Water District with chloramine disinfection, EMWD has become reliant on chloramine disinfection to manage long transmission lines and longer detention times due to on-going water scarcity.

As is common in systems utilizing chloramines for secondary disinfection, EMWD experiences chronically low disinfection residuals at certain points in their distribution system –especially in warmer months. In2016, UGSI Solutions partnered  with  EMWD  to  pilot the Monoclor® RCS chloramineresidual management system at one of the two 5.5 million gallon Landmark reservoirs. The site has two 5.5 million gallon tanks with a common inlet and outlet. The site was ideal for performance comparison as one tank could act as a control to the other tank utilizing the trailer mounted Monoclor® system.

The EMWD Monoclor® RCS trailer used a skid‐mounted Microclor® onsite sodium hypochlorite generator (OSHG) thatprovidedup to 40 pounds per day of chlorineequivalent, a liquid ammonium sulfatefeed system, and a Tank Shark® reservoir mixing system which provided 150 gallons per minute of mixing energy inside of the reservoir. A water booster pump was not required because EMWD had water pressure available at the site.  The maintenance of the tank’s chemical equilibrium was aided by the use of liquid ammonium sulfate and a constant concentration of 0.8% sodium hypochlorite from the OSHG for monochloraminegeneration. The chemical metering pumps were all located inside the trailer with chemical feed tubing leading to the Tank