Oro Loma Sanitary District is nearing completion on an innovative upgrade project to improve the quality of the treated water returned to the San Francisco Bay.


Exceeds Standards of the Clean Water Act

The upgrade goes beyond the standards of the Clean Water Act to include removal of nutrients to the Bay. Oro Loma uses
a combination of mechanical, biological, and chemical methods to remove

solids and pathogens from incoming wastewater before returning the treated water to the Bay. The upgrade focuses on removing residual nutrients from the water.

Why too many nutrients are bad

In the right place, nutrients are good and help support the growth of plant life.

However, too many nutrients in the water can lead to undesirable cycles of algae growth and decay that deplete oxygen levels and hurt fish and other organisms that live in the Bay.

Oro Loma leads the way

With this project, Oro Loma becomes one of the first of 37 agencies in the Bay Area to take action in response to growing concerns about nutrient levels in the San Francisco Bay. Oro Loma Sanitary District and Castro Valley Sanitary District, which co-owns the treatment plant, have made the proactive decision to implement treatment enhancement to reduce nitrogen loads to the Bay before they become a more significant concern.