San Francisco Southeast Water Pollution Control Plant SEP 020 Headworks Project
Project Overview
Space is extremely limited, flows are widely varied, and performance goals and grit loading is very high at the Southeast Treatment Plant (SEP), where the San Francisco Public Utilities Commission (SFPUC) is currently constructing a new state-of-the-art, 250-mgd headworks to treat flow from the Bayside combined sewer system. The SEP is San Francisco’s largest and oldest wastewater facility, serving the Bayside Watershed on the east side of the city and nearly two-thirds of the San Francisco’s residents. It receives 80 percent of the city’s total annual flow.
This new all-weather headworks will replace the capacity of two existing aging headworks and address the needs of various stakeholders including the community. Key features include:
- Improving the removal efficiency of screenings and grit from influent wastewater to protect downstream processes.
- Reducing operations and maintenance requirements and costs over the life of the project.
- Increasing operational flexibility to address varied operating conditions (e.g., varied flow and load conditions).
- Increasing reliability and resilience.
- Protecting the community from odor and noise impacts.
- Benefiting the neighborhood both functionally and aesthetically.
- Accommodating climate change, including expected sea level rise.
Carollo’s design and construction services teams are working in close collaboration with SFPUC and construction manager general contractor Sundt-Walsh to deliver this award-winning, sustainable project, which is the first headworks project in the country to earn an Envision Gold Award. The Envision system examines the impact of sustainable water infrastructure projects as a whole, through five distinct categories, which contribute to the positive social, economic, and environmental impacts on a community. These include quality of life, leadership, resource allocation, natural world, and climate and resilience. In addition, the project was featured twice as the cover article in the Water Environment Federation (WEF) publication Water Environment and Technology (WE&T).
Major challenges posed by this project include very tight site space, high groundwater, poor soils, a heavy urban setting, and extremely high influent grit loads from the combined sewer system. In response, the design team developed several innovative solutions in the areas of hydraulics, flow distribution, vertical (stacked) construction, and foundation design.
To address market conditions and keep this $400 million project on budget despite the rapidly rising costs of construction in the Bay Area, the SFPUC-Carollo-Sundt-Walsh team implemented a number of innovative design features to control cost without sacrificing stakeholders’ goals or impacting the overall completion schedule.
Results and Highlights
The new headworks handles extreme grit loads, more than 10 times the national average, resulting from San Francisco’s combined sewer system
A wide range of flows (30 to 250 mgd) is accommodated by an innovative hydraulic design and stacked configuration within an extremely tight space
As part of the preliminary design, selecting the grit and handling technology involved the most comprehensive pilot testing in the country over a one-year period
The project fulfills several commitments to the community, including minimizing odor and noise impacts, enhancing aesthetics, and providing educational opportunities through designated areas for public tours
Project Awards and Accolades
Institute for Sustainable Infrastructure