Robert A. Skinner Water Treatment Plant

In operation since 1976, the Skinner Plant is one of five filtration plants in the Metropolitan Water District, serving 2.5 million customers. The plant features both conventional and direct filtration and consists of seven treatment modules, eleven flocculation basins, eight settling basins, 124 filters, and a 110 million gallon finished water reservoir.

Under this contract, Shimmick increased the plant’s capacity from 520 MGD to 630 MGD, and enabled the owner MWD to disinfect raw water from Lake Skinner. Shimmick retrofitted the existing plant with a new oxygen/ozone disinfection system. The upgraded plant included the following new major facilities:

• Six ozone contactors and five 4,000-pound-per-day ozone generators.
• Three 37,000 gallon liquid oxygen (LOX) storage tanks with feed equipment.
• 630 MGD plant influent structure.
• Three chemical storage and feed systems to control pH, taste and odor.
• New power substation and electrical switchgear building.
• 60 MGD coal removal system.
• 34 MGD washwater clarification system.
• 60 MGD washwater return pump station.
• Interconnecting pipelines with diameters ranging from five to twelve feet.

Three other expansion contracts were also under construction at the same time. Shimmick led the effort to maintain the project schedule alongside other contractors’ work by staging intermediate milestones to assure smooth coordination between jobs. The Skinner Plant remained in operation throughout the construction of the project.