Biosolids to Amend California Soils

Oro Loma Initiates Use of Biosolids to Amend California Soils

The District’s 10-Year Strategic Plan includes exploring alternatives for the beneficial reuse of biosolids. The Strategic Plan goal is aligned with Governor Brown’s emphasis on healthy soils in the state.

Biosolids are the nutrient-rich organic byproduct of the wastewater treatment process. They contain essential plant nutrients and organic matter, which can be applied as fertilizer to improve and maintain productive soils and stimulate plant growth.

Oro Loma produces an average of 8,000 tons of biosolids each year. Presently, all this material is recycled as alternative daily cover at the Altamont Landfill. While this practice is the least costly, it neglects the benefits that biosolids can provide to replenish the state’s agricultural land.

Upon researching options, District staff recommended and the Board approved a pilot study to evaluate the use of biosolids for land application in the Central Valley. The pilot will be conducted in partnership with Synagro, a company that specializes in the management of biosolids throughout the United States. Synagro has partnerships with farmers throughout the Central Valley, employs a
professional approach to environmental compliance, and is the market leader in the San Francisco Bay Area.

During the two-year pilot, the District will supply approximately 50% of its biosolids to Synagro. Staff will visit the land application site, observe the benefits of land application on crop yields, and review
the application process.

Although the new alternative is slightly more expensive, staff anticipates managing the new option within the existing budget constraints.