Bay Area Regional Nutrient Planning Update

Presentation Description: The Bay Area Clean Water Agencies, working on behalf of the 37 major municipal wastewater treatment plants discharging to San Francisco Bay (Bay), has been leading studies for more than 10 years to advance a nutrient management strategy. The vision has been to use science to evaluate the health of the Bay ecosystem coupled with strategies for nutrient management by wastewater treatment facilities Recent algal blooms in August 2022 and 2023 have accelerated the need to develop such a strategy as nutrient limits across the Bay are looming.

The vision from the onset has been to develop a menu of nutrient management options to inform decision making. The menu includes treatment plant improvements (optimization, sidestream, and plant upgrades), water recycling, and nature-based solutions.

The session will begin with an update on the nutrient watershed permit, followed by details on the recently completed recycled water study that will inform the overall strategy (HDR and Woodard & Curran, 2023). The recycled water component will include current and projected recycled water volumes, costs, nutrient loads diverted from the Bay, drivers and barriers for implementing reuse projects. Potable reuse (emphasis on groundwater recharge and surface water augmentation) is expected to expand with most projects being implemented after year 2035.

Following the regional overview, a case study will be presented by the City of San Jose on past, present and future nutrient management efforts at the San-José-Santa Clara Regional Wastewater Facility. The case study will include the facility’s previous upgrades that incorporated denitrification decades ago, ongoing plant optimization efforts, current and future recycled water plans, as well as the potential for nature-based solutions to manage nutrients.

The session will conclude with a comparison (both economic and non-economic) of the nutrient reduction potential for reuse projects to the other options in discussion: treatment plant improvements or nature-based solutions. This watershed-based approach that considers science along with development of a menu of nutrient management options has the potential to serve as a template for other watersheds.