San Francisco Bay Summer 2022 Algal Bloom
and
SFPUC’s Plans for Nutrient Reduction
SFPUC Wastewater Enterprise
December 13, 2022
1Presentation for San Francisco Public Utilities Commission SUMMER 2022 ALGAL BLOOM
2 Summer 2022 Algal Bloom:
Nature and Extent of Event
• Algal blooms are overgrowths of
algae in water
• Major event in August 2022
• Started around Alameda & Oakland
• Spread to the South Bay and Lower South
Bay with additional impacts in Central Bay
and San Pablo Bays
• Species: Heterosigma akashiwo
• Toxic to fish
• No recorded health effects to humans
3 chlorophyll-a
Summer 2022 Algal Bloom:
Cause
• Trigger unknown
• Research is ongoing
• Potential factors:
• sunny days
• less turbid water
• calm winds
• High nutrient loads resulted in
more severe impacts
• Nutrient compound of concern is nitrogen
• Bloom died off after consuming nitrogen
• Nutrients did not cause the event
4 WASTEWATER TREATMENT PLANTS:
ROLE, RESEARCH, AND REGULATION
5 Nutrient Research in San Francisco Bay
6 • 37 wastewater treatment plants are the largest
contributor of nutrients (2/3 of contribution)
• For 10+ years, wastewater agencies (BACWA*),
NGOs, regulators, and scientists are
collaborating on an ongoing stakeholder-
driven science program to inform regulation
• Since 2013, wastewater agencies have
contributed >$14M towards the science program
*Bay Area Clean Water Agencies (BACWA) = joint powers
authority of wastewater agencies
Nutrient Regulation in San Francisco Bay:
Nutrients Watershed Permit
• Nutrients Watershed Permit
requirements:
• Monitoring nutrients in wastewater
• Special studies on wastewater treatment,
recycled water, and nature-based solutions
• Funding further science in SF Bay
(currently $2.2 million /year from
wastewater agencies)
7 WASTEWATER TREATMENT PLANTS:
NUTRIENT REDUCTION PROCESSES
8 Simplified Wastewater Treatment Process
9 Preliminary + Primary Secondary Disinfection
Biosolids
Re-use
Sidestream Treatment
10 Sidestream
Treatment
Biosolids
Re-use
Preliminary + Primary Secondary Disinfection
Nitrogen Removal
Preliminary+ Primary Secondary Nitrogen Removal
Fullstream Treatment
11 Nitrification/
Denitrification
Disinfection
Biosolids
Re-use
SFPUC’S PLANS FOR NUTRIENT
REDUCTION
• Treasure Island
• Southeast Water Pollution Control Plant
12 13
Technology Evaluations
SBR - Sequencing batch
reactor
MBBR - Moving bed
biofilm reactor
IFAS - Integrated fixed
film activated sludge
New Treasure Island Water Resource
Recovery Facility
14 • Facility will produce high
quality recycled water
• Full stream nitrogen removal
(Membrane Bioreactor)
• Anticipated Completion: 2026
Draft facility layout for discussion purposes
Southeast Treatment Plant:
Planning for Future Nutrient Removal
15 Southeast Treatment Plant:
Planning for Future Nutrient Removal
16 LEGEND
Future
nutrient
treatment
facility:
QUESTIONS?
17