Disinfection Byproduct Reduction With A Novel Multi-Contaminant Treatment Approach

Treatment train includes ozone, BAC, and ion exchange

The Central Valley of California has many potable groundwater systems operating on subsurface wells that have primary and secondary regulatory drinking water issues. Given the very challenging water quality as recognized the Division of Drinking Water, the City of Lemoore, CA water supply (consisting of multiple well clusters) is exceeding the compliance targets for disinfection byproducts (DBPs), mainly total trihalomethanes (TTHMs). 

The City, under a compliance order from the State of California to bring their system into compliance, considered multiple options for treatment in accordance with their Corrective Action Plan (CAP). A 10-month extensive small-scale field pilot study was undertaken to test a unique combination of ozone, granular activated carbon (GAC)/biological activated carbon (BAC), and ion exchange on what was considered the worst water quality on one of the City’s well clusters of to achieve the primary and secondary water quality objectives with the primary goal of TTHM compliance. With this treatment train via physical/chemical and biological means, TTHMs were reduced by over 75 percent, ammonia reduced by 95 percent, color reduction of 90 to 95 percent, and final chlorine demand of the treated water was reduced by over 80 percent.

With all primary and secondary water quality objectives being achieved, the technology was selected and awarded a progressive design-build contract for full-scale implementation at two well clusters that serve the city’s entire population of 26,000. The two treatment systems will provide over 14 MGD of new treatment capacity, representing one of the largest groundwater treatment plants in the U.S. to be constructed in 2020. This webinar will present the results of this work, including details on piloting, methodology, treatment techniques, design parameters, lessons learned, and operating costs.