Groundwater PFAS Treatment Facility

Groundwater PFAS Treatment Facility

Alameda County Water District (ACWD) blends local groundwater with purchased water from the San Francisco Public Utilities Commission (SFPUC) at ACWD’s Blending Facility in Fremont, California. The groundwater is from ACWD’s onsite Peralta-Tyson (PT) wellfield and the nearby Mowry wellfield, which each have eight production wells (total 16). The groundwater is blended with low-hardness SFPUC water to meet ACWD’s hardness goals. Per- and Polyfluoroalkyl Substances (PFAS) have recently been detected in the Mowry and PT production wells. The California State Water Resources Control Board’s Division of Drinking Water (DDW) has established notification levels (NLs) and response levels (RLs) for four PFAS: perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorobutanesulfonic acid (PFBS), and perfluoroctanesulfonic acid (PFHxS). California regulatory standards for PFAS are expected in the future, including NLs and RLs for PFAS and maximum contaminant levels (MCLs) for a class of PFAS including PFOA and PFOS. Additionally, a federal MCL for PFOA and PFOS is expected in 2023. While the Blending Facility has a capacity of 48 million gallons per day (MGD), current groundwater production is limited by hardness and PFAS goals. Meeting a 150-milligrams per liter hardness goal limits production to 32 to 36 MGD, while achieving a PFOS concentration below the NL further limits production to 22 to 24 MGD. Achieving the PFHxS NL would further limit the production to approximately 18 MGD. In light of the impact that PFAS has had on production at the Blending Facility and the anticipated MCLs, ACWD is designing a PFAS treatment system that will provide sufficient treated groundwater below the detection limit for both PFOS and PFOA and produce drinking water below the NL and RL requirements. The project includes the installation of a 15 MGD groundwater PFAS treatment system to bring PFAS concentrations below detection limits, to be constructed in two or more phases. The treatment technology to be implemented is ion exchange (IX). The project will thus restore the Blending Facility to pre-PFAS detection flows.

Fremont

Alameda

Citywide

California Air Resources Board (ARB), California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW), California Department of Parks and Recreation, California Department of Toxic Substances Control (DTSC), California Department of Transportation, District 4 (DOT), California Department of Transportation, Division of Aeronautics (DOT), California Department of Transportation, Division of Transportation Planning (DOT), California Department of Water Resources (DWR), California Highway Patrol (CHP), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Public Utilities Commission (CPUC), California Regional Water Quality Control Board, San Francisco Bay Region 2 (RWQCB), California State Lands Commission (SLC), Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Drinking Water, District 4, State Water Resources Control Board, Division of Water Quality, State Water Resources Control Board, Division of Water Rights, State Water Resources Control Board, Divison of Financial Assistance

Water Facilities (PFAS Treatment)(Type Ion Exchange, MGD 15)

water treatment

Biological Resources, Cultural Resources, Mandatory Findings of Significance, Tribal Cultural Resources