West Basin MWD awards $537k contract for Carson recycling plant chemical tank replacement

West Basin MWD awards $537k contract for Carson recycling plant chemical tank replacementThe district selected MMC, Inc. to install a new 9,100-gallon fiberglass tank, resolving a 2022 structural failure and ensuring reliable recycled water treatment for the nearby Marathon Refinery.

MMC, Inc. secured the construction contract with a low bid of $467,300, plus a 15% contingency.

The new 9,100-gallon fiberglass-reinforced plastic tank replaces an original 8,000-gallon tank that suffered a critical failure in August 2022.

The project is fully funded by the Marathon Refinery through fixed capital recovery payments.

Sodium hypochlorite is essential at the facility for microfiltration, reverse osmosis, and nitrification processes.

The West Basin Municipal Water District (WBMWD) is moving forward with a permanent fix for its bulk chemical storage at the Juanita Millender-McDonald Carson Regional Water Recycling Plant (JMMCRWRP). During an August 19, 2026 meeting, the district's Engineering and Operations Committee advanced a $467,300 construction contract, plus a 15% contingency, to La Palma-based MMC, Inc. The project will install a new 9,100-gallon fiberglass-reinforced plastic (FRP) sodium hypochlorite tank. It replaces an original 8,000-gallon FRP tank built in the 1990s that experienced a non-repairable structural failure and leak in August 2022. Since the failure, the district has relied on a temporary 6,900-gallon high-density polyethylene rental tank to maintain uninterrupted operations. Sodium hypochlorite is a critical chemical at the advanced treatment facility, used to minimize microfiltration membrane fouling, support reverse osmosis membrane cleaning, and provide breakpoint chlorination for the nitrification process. The treated product water is supplied directly to the Marathon Refinery for boiler-feed and cooling tower applications. A district engineer noted that the project design was temporarily placed on hold while WBMWD negotiated a funding agreement with the Marathon Refinery. With the agreement now fully executed, the refinery is fully funding the tank replacement project through fixed capital recovery payments. MMC, Inc. was selected as the lowest responsive and responsible bidder among four competitors, beating out bids ranging from $659,860 to $836,413. While the original engineer's estimate was $300,000, staff noted that the variance was primarily driven by fluctuations in the manufacturing cost of the fiberglass tank itself. Staff requested an elevated 15% contingency—totaling $70,095—due to the age of the 27-year-old chemical containment area. The higher contingency provides a buffer to address any unforeseeable underground wiring or field conditions during the short, three-month construction window, ensuring the project remains on schedule.