The City of Richmond is located 16 miles northeast of San Francisco on the western shore of Contra Costa County. the City’s Water Pollution Control Plant, which was constructed in 1958, treats wastewater for reuse and discharge. The plant uses a combination of treatment processes including influent pumping, grit removal, and disinfection.
It was determined that during peak wet weather flows, the plant had insufficient capacity to meet these demands. To alleviate the strain on the existing water infrastructure without having to increase the capacity of all the unit processes, the City decided to build a wet weather equalization structure to adequately treat incoming flows and reduce the risk of harming public health and the environment.
To implement this $18 million Wet Weather Storage Basin Project, the City selected the Carollo Engineers led design-build team which included Overaa Construction and DN Tanks. Key elements of the project include a new 40-mgd submersible pump station, 5-million-gallon above grade, prestressed concrete storage tank, a biofilter for odor control, a new electrical feed and standby generator, and over 1,500 feet of pipeline connecting the storage tank and pump station.
During significant storm events, peak wet weather flows from the collection system are diverted and stored in the storage tank which prevents back-up or overflow situations at the City’s wastewater treatment facility. After plant influent flows normalize, the stored wet weather flow is diverted to the treatment plant for processing.