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Treatment Process
Treatment Process
After wastewater enters the San José-Santa Clara Regional Wastewater Facility (Facility), it undergoes a three-step treatment process to remove solids, pollutants, and pathogenic bacteria. Machinery and gravity separate solids from the wastewater. Added bacteria clean the water pollutants before the flow enters the advanced filter process. The treatment process produces water that is 99% purified and is subsequently discharged into the Bay.

Did you know? The Facility's largest annual peak flows arrive on Super Bowl Sunday!

Headworks (Pretreatment)
Original structure
The original headworks structure has operated continuously for over 50 years. Large bar screens remove rags, sticks, rocks, and other debris that could otherwise clog machinery. The debris are then transported to the landfill.

The original structure system has never been taken out of service for maintenance. If this system failed, it could result in a raw sewage spill onto Facility grounds. Berms and other protections surround the system to prevent sewage from entering the Bay.

New structure
The new headworks structure is in its final testing phase. The system was built to avoid accidental sewage spills due to mechanical malfunction, earthquakes or other unexpected events.

Primary Treatment
This 24-hour physical process removes about 50 percent of wastewater contaminants. In large tanks, the flow is slowed to allow gravity to separate large particles. This process mimics the natural processes of creeks and rivers, where sediments settle to the bottom.

Fiberglass bars, or flights, move across the tank surface to skim off fats, oils, and grease. Flights gradually rotate from the top to the bottom and the settled solid particles are moved into the digesters.

The pollutants and solid material removed during the three treatment steps are separated from the liquid flows in digester tanks.

It takes 25 to 30 days for anaerobic bacteria to stabilize unwanted material and reduce the pathogens and other disease-causing organisms in the solids. Anaerobic bacteria operate best without oxygen and at about 98 degrees.

Digesters produce methane gas, which meets 35% of the Facility's energy needs.

Secondary & Tertiary Treatment