Facing years of aging infrastructure and inadequate sewer system capacity, the City of San Mateo was issued a Cease & Desist Order by the State of California Regional Water Quality Control Board to eliminate sanitary sewer overflows caused by rain induced inflow and infiltration. The city evaluated two options: conveying peak design storm flows to the wastewater treatment plant (WWTP) and building in-system storage within the sewer system. The in-system storage approach was selected as it eliminated the need for larger capacity at the WWTP, reducing overall capital costs. After an evaluation of 50+ locations for a 5.3 million gallon underground wet weather flow storage structure, the city pursued the acquisition of easements and embarked on an expansive public outreach effort. The design for the in-system storage approach is based on a real-time control strategy to operate the new structure and the pumping systems within the collection system. Weather forecasting will determine the activation of storage and the wet weather treatment mode at the WWTP, an approach that has required in depth training of the operations team. Overall, coordination with residents, developers, multiple city departments, and an outside agency for the easements has been essential for a successful project.

Proficiency Level

Applied

Learning Objectives
  1. Develop an objective evaluation method and criteria to guide programmatic and project specific decisions which account for technical, environmental, social, and economic considerations.
  2. Communicate engineering and science to the general public and convince governing bodies of adopting alternative operational approaches.
  3. Prepare a community outreach and engagement strategy to obtain input to align the needs of community stakeholders with the goals of a project.

Contributor/Source

Deryk Daquigan;Azalea Mitch;Dan O’Leary

Claim CEUs

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