The Sunol Valley Water Treatment Plant Ozonation Project will improve water quality for the San Francisco Public Utility Commission’s 2.7 million Bay Area residential, commercial and industrial customers by implementing a raw water ozonation system to mitigate taste and odor events. The plant treats raw water mainly from its two local source water reservoirs that have experienced increasing algal levels. Climate change effects from drought are increasing the frequency, size and duration of the algal growth and blooms that are at the heart of the taste and odor events.

After evaluating several alternatives, the San Francisco Public Utilities Commission (SFPUC) selected raw water ozonation as the long-term solution. Ozonation removes taste and odor by breaking down compounds into harmless substances, then reverts safely to oxygen. By implementing this system, the goal is to reduce the concentration of taste and odor-causing compounds in the raw water such that the respective concentrations of geosmin, MIB and TCA are no greater than 5 ng/L in the finished water.

Beyond taste and odor control, the project will achieve several secondary objectives, including additional primary disinfection with ozone as part of a multi-barrier disinfection strategy alongside the existing disinfection process, improved treatment reliability, additional control of chlorinated disinfection by-products and oxidation of emerging contaminants.

The plant is in the Sunol Valley of Alameda County, California on land owned by SFPUC. The project includes several primary components to be constructed on site: a liquid oxygen and nitrogen facility, an ozone generation building, an ozone contactor structure, an open-loop cooling water pump station and a calcium thiosulfate facility. In addition, the project incorporates supportive improvements such as yard piping, a new access road and electrical work.

Quotes

“The Sunol Valley Water Treatment Plant Ozonation Project will help us ensure that high-quality water can be delivered to our customers year-round. Our design for this new facility is a sign of our commitment to sustainability, not only in our infrastructure, but in how we manage the watershed lands of the region.”
— San Francisco Public Utilities Commission

“Receiving the ISI Envision Silver Award reflects CDM Smith’s commitment to provide sustainable and forward-thinking water solutions to our clients. Our team’s SVWTP ozonation design showcases our innovative approach to deliver an advanced water treatment solution to support SFPUC.”
— Servando Molina, CDM Smith Client Service Leader

“Congratulations to the SFPUC and the entire project team behind the Sunol Valley Water Treatment Plant Ozonation Project. By implementing advanced raw water ozonation, this project will improve regional water system reliability and quality, address climate change impacts, and create additional opportunities to benefit the local environment and community.”
— Anthony Kane, President & CEO of the Institute for Sustainable Infrastructure (ISI)

Verified Sustainability Achievements

San Francisco Environment Code Chapter 7 Municipal Green Building Requirements mandate that large construction projects pursue verification through a comparable sustainability system when pursuit of LEED Gold Certification is not appropriate. For this project, SFPUC chose the Envision Framework, administered by the Institute for Sustainable Infrastructure (ISI). Verification through ISI resulted in strong performance across multiple sustainable categories, with several notable achievements highlighted below. 

Enhanced Community Quality of Life – This project delivers significant benefits to the community. The plant supplies treated water to the San Francisco Regional Water System, which serves as a critical resource for the Bay Area. The Bay Area Water Supply and Conservation Agency (BAWSCA) provides regional water planning and conservation services through this system, supporting over 1.8 million residents and more than 40,000 businesses across 26 member agencies in Alameda, Santa Clara and San Mateo counties.

Resource Allocation – The project involves conveying large quantities of both raw and treated water without increasing potable water use at the plant. The ozonation system incorporates flowmeters and water level measurements at multiple stages to monitor and control operations, as well as to identify and address process inefficiencies. In addition, the project supports key energy sustainability goals, with at least 95 percent of its energy requirements being met through renewable sources.

Minimize Light Pollution  – The project carefully considered lighting needs and impacts including ensuring compliance with backlight, uplight and glare (BUG) standards. To minimize glare from the solar panels that will be installed on the ozonation building roof, a parapet was added as part of the design. All new lighting fixtures required for safety will be directed downward and strategically sited and shielded to prevent nuisance lighting from affecting offsite areas.

Enhance View and Local Character – While the site is in a remote area, portions of the project site are visible from Calaveras Road, which Alameda County designates as a scenic route. To preserve and enhance views and local character, the new buildings are designed to complement existing structures and blend with the surrounding environment. New trees and landscaping will be planted to replace those removed at the plant during construction, providing natural screening for the new facilities.

Assess Climate Change Vulnerability – A long-term vulnerability assessment (LTVA) and adaptation plan for SFPUC identifies climate change threats to the Hetch Hetchy Regional Water System, including the the Sunol Valley facility. Multiple models were used to evaluate how climate change, combined with external drivers such as water demand, may impact the system over a 50-year horizon. These simulations incorporated project changes in climate and weather patterns, watershed hydrology, system operations, long-term demand, water quality, and financial considerations.

Infrastructure Integration – The project will be fully integrated with the regional water system to support regional water supply and distribution performance and reliability. The ozonation control system will also connect to the San Francisco Water SCADA System, enabling remote monitoring and faster response times in the event of issues with the water conveyance portions of the process. The project team also sought to mitigate the potential for power outages to cause cascading failures. It incorporated electrical system upgrades to improve reliability, protect equipment from power surges, protect existing facilities from voltage fluctuations and provide emergency power backup.