PUC workshop recommends new off‑site Class A biosolids facility; staff frames SSIP as $7 billion program with affordability guardrails

San Francisco — In a long afternoon workshop on July 10, the San Francisco Public Utilities Commission and staff moved through the first of three SSIP validation workshops and recommended a path forward on the city—s biosolids treatment needs while framing the larger sewer system improvement program (SSIP) as a roughly $7 billion, multi‑decade capital program.

Karen Kubith, director of the service management program, told the commission that staff and the program manager validated facility conditions and identified four biosolids options: 1) continue repairing and maintaining the existing in‑place facilities; 2) rebuild in place using similar technologies; 3) build a new off‑site facility to produce Class A biosolids with modern digestion, dewatering and cogeneration and accommodate fats/oils/grease and food‑waste co‑digestion; and 4) a longer‑term advanced drying/energy‑recovery option that would produce a drier end product or ash.

After briefing the commissioners on condition assessments, operational reliability gaps and community impacts near the Southeast plant, staff recommended Option 3 as the preferred near‑term approach: a new site, modern treatment trains and state‑of‑the‑art odor controls, with the program staged so Option 4 could be added later if market and technology conditions justify the extra investment. Staff cited a capital cost range of roughly $1 billion to $2 billion for the biosolids component depending on the chosen scope and phasing.

Staff stressed the importance of affordability in the SSIP decision. Todd Reistrom, chief financial officer, placed the SSIP inside a larger 20‑year capital framework and told the commission that a program of roughly $7 billion over two decades would, under the financial plan adopted in February, translate to a multi‑year rate path that staff has modeled to hold average combined water and sewer bill increases to single digits annually (the plan calls for a larger near‑term increase during the first 12 years and lower increases thereafter). Reistrom said staff—s financial plan aims to keep the combined bill under roughly 2.5% of median household income over time and that community assistance programs would continue to provide discounts for qualifying customers.

On technical drivers, program management adviser Marty Dorworth summarized nine months of on‑the‑ground validation work, highlighting grit intrusion in headworks and tanks, corrosion and limited redundancy at pump stations and key electrical equipment as recurring causes that pushed projects into the recommended package. Staff also committed to pilot testing UV disinfection and other technologies before recommending adoption as part of the base SSIP package.

Commissioners asked for more detail on flood‑control benefits, green infrastructure performance and how projects would be staged to control near‑term rate impacts. Karen Kubith said staff would present additional modeling, cost‑benefit comparisons and implementation schedules in subsequent workshops and at the August meeting.

What happens next: Staff will return to the commission with project‑level scoring under the triple‑bottom‑line framework, refined cost estimates and implementation timelines. Any rate proposals that implement the SSIP will come back to the commission with required affordability analyses and updates to community assistance programs.