South San Francisco-San Bruno Water Quality Control Plant

Upgrading from conventional digestion to Omnivore® high-solids digestion saves money, space and delivers future flexibility

South San Francisco-San Bruno Water Quality Control Plant (WQCP) is a nine million gallon per day (MGD) facility that serves 100,000 people in California’s Bay Area. Master planning indicated a need to overhaul or rebuild its five aging digesters to maintain regulatory compliance and allow for projected load growth—all while maintaining its existing physical footprint.

Rather than re-build all five digesters, third-party engineering analysis indicated that the most cost-effective way to revamp the facility’s digesters would be to leverage Anaergia Omnivore high-solids digestion technology to build just three new digesters: two conventional and one Omnivore. The high-solids approach effectively offset the need to re-build two additional digesters . The third-party analysis projected this solution would reduce lifecycle costs by more than 11%.

The Omnivore system combines Anaergia’s powerful and energy-efficient OmniMix submersible mixer and service box with our robust recuperative thickening technology to triple digester capacity—providing three times the digestion capacity and three times the biogas production in the same tank volume.

The high-solids digestion enhancement has reduced biosolids management costs, and provided the plant with redundancy, operational flexibility, and future-proofing to accommodate load growth as well as external waste streams. The WQCP tapped the added digester capacity and high-solids mixing capability to partner with neighboring solid waste agency, South Bayside Waste Management Authority (SBWMA). SBWMA delivers landfill-diverted organic waste to the WQCP Omnivore digester for co-digestion. This win-win approach enhances WQCP energy neutrality, promotes solid waste recycling, and supports local greenhouse gas reductions initiatives.

  • Project Location: South San Francisco, California
  • Startup: 2020
  • Turnkey Omnivore® high-solids anaerobic digestion system

Key Technologies

OmniMix™ mixer with patented service box

Sludge Screw Thickener


  • Municipal Wastewater Biosolids, Organic slurry from Anaergia OREX™ and OPS
  • Organic slurry from Anaergia OREX™ and OPS
  • Outputs

  • 3x biogas production
  • Impacts

  • Eliminated the need to rebuild 2 new digesters.
  • Tripled solids handling capacity & provided redundancy.
  • Reduced landfill methane emissions
  • Enhanced compliance with state regulations
  • Carbon-negative biogas and electricity production

    Chat with us to discuss how we can work together to help communities, cities, industries to turn their waste into renewable fuel.