Overlooking the San Francisco Bay, the Sausalito-Marin City Sanitary District’s (SMCSD) wastewater treatment plant has a major challenge wrapped up in a million-dollar view. The area’s treatment facility needed upgrades, but sits on a highly-constrained site on the water’s edge leased from the National Park Service. Woodard & Curran applied innovative approaches to design a suite of improvements to the facility along with facilitating the relevant permitting requirements needed to operate within the limited space.
Woodard & Curran’s improvements to SMCSD’s WWTP improved the plant’s performance, provided additional redundancy, and decreased maintenance and operator labor requirements. The design phase consisted of a new headworks (screening and grit), primary clarifier, pumps, fixed film reactor upgrades, dewatered sludge handling, equalization and tertiary filtration and roadway improvements to allow trucks easy access for sludge removal.
MAKING USE OF SPACE WITH TURNTABLES
Typically used in high rise buildings and by transportation systems like BART, Woodard & Curran used truck turntables to preserve scarce land for treatment facility improvements instead of vehicle turn-around space. To make room for the equalization basin, primary clarifier, and access road, Woodard & Curran designed a soil nail retaining wall to stabilize the nearby hillside. Since the retaining wall is visible from passing boats, it is designed with a rock texture and planting pockets to improve aesthetics.
NAVIGATING THE REGULATORY ENVIRONMENT
Woodard & Curran obtained project approval from the National Park Service and a permit amendment from the San Francisco Bay Conservation and Development Commission. The upgraded wastewater plant will improve treatment reliability by eliminating wet weather blending for up to a five-year event, increase trickling filter capacity, provide equalization storage, and replace secondary polishing.