San Francisco International Airport Recycled Water System

San Francisco International Airport (SFO) has a long-term goal of recycling 100 percent of the sanitary and industrial wastewater generated across its campus to reduce reliance on potable water supplies and advance environmental stewardship. To help achieve that vision, SFO launched the Recycled Water System Project, a major initiative that expands water reuse throughout the airport while improving the quality of water discharged to San Francisco Bay. The project builds on previous investments at the Mel Leong Treatment Plant and reflects SFO’s proactive approach to sustainability, resilience, and emerging water quality challenges.

As part of a progressive design-build partnership, Carollo Engineers is planning and designing an airport-wide recycled water system that will transform sanitary and industrial wastewater generated across the SFO campus into a reliable local water resource. The project includes a new advanced water treatment plant, a PFAS treatment demonstration facility, and the storage, pumping, conveyance, and distribution infrastructure needed to deliver recycled water throughout the airport. When complete, the system can provide up to 1.5 million gallons per day (mgd) of recycled water for terminals, administrative facilities, landscape irrigation, and other non-potable uses, helping expand water reuse across airport operations and reduce reliance on potable water supplies.

The project incorporates several innovative treatment strategies designed to maximize water recovery. By combining sanitary and industrial wastewater treatment, advanced purification, PFAS evaluation, and recycled water distribution, the project creates a fully integrated water reuse system tailored to the needs of a major international airport. A multi-barrier treatment process that includes dissolved air flotation, ozonation, biologically active carbon treatment, ultrafiltration, reverse osmosis, and ultraviolet disinfection will produce high-quality recycled water for a wide range of non-potable uses across the SFO campus. Additionally, a PFAS demonstration facility will evaluate treatment strategies for emerging contaminants and help inform future PFAS treatment approaches.

Once operational, the Recycled Water System Project will demonstrate how airports can transform wastewater into a valuable local resource while advancing ambitious sustainability goals. By reducing potable water demand, improving water quality, and supporting SFO’s vision of becoming a net-zero water campus, the project will deliver lasting benefits to both the airport and the surrounding environment. The project’s integrated approach to advanced treatment, PFAS evaluation, and airport-wide water reuse provides a model for how large, complex facilities can build more resilient and sustainable water systems.