Chloride Compliance Alternatives Evaluation

The City of Brentwood Wastewater Treatment Plant faced challenges with complying with effluent limitations for chloride. To help their client find a feasible solution to this problem, RBI conducted a study that evaluated several alternatives to achieve compliance with the new chloride limitations. Suggested alternatives included alternative water supplies, such as varying the blending of surface water and groundwater seasonally; residential self-regenerating water softener controls (i.e., reduced reliance on water softeners); reduced effluent discharge to Marsh Creek (including maximizing use of recycled water, and a zero discharge land application assessment); reverse osmosis treatment; and conveyance of treated wastewater to an existing outfall in the Delta.

RBI staff drew upon a wide range of technical services to evaluate the feasibility of these alternatives.  Modeling was used to simulate chloride and hardness in the potable water distribution system and wastewater collection system to assess the optimal blending of surface and groundwater supplies and the impact of reduced reliance on water softeners. RBI also prepared preliminary designs of pumps and a pipeline that would be necessary to convey treated wastewater to an alternative discharge point. Preliminary design calculations were also made by RBI for a zero discharge land application facility, in addition to preliminary cost estimations of feasible alternatives.

RBI was able to use this study to recommend a viable approach that provided a cost-effective solution that the City is currently developing for future implementation to bring the wastewater treatment plant into compliance for chloride.