Biosolids Program

Program Information

Biosolids have the potential to harm human health and cause environmental degradation due to the heavy metals, live pathogenic organisms, and chemical pollutants they may contain. The application of Biosolids to land is restricted to certain areas of the county to reduce the potential for human health impact. Biosolids storage, application, chemical and biological quality, and the method, rates and times of application are controlled through a permit process. Inspections and sampling are conducted by Environmental Health to assure that regulatory standards are met.

What Are Biosolids?

Biosolids are solid or semi-solid waste materials derived from the processing of municipal wastewater and/or septic waste. They can be applied to land as a soil additive or fertilizer. In addition to the potential threat to human health and the environment, when Biosolids are applied to lands in agricultural areas, there is concern that the value of crops produced and the land itself could be impacted.

Permit Information

What do I need to do to obtain approval to apply Biosolids to land in Yolo County?

A permit for application of Biosolids is required. Permits will only be issued after the applicant demonstrates that the site proposed meets the ordinance requirements. For example, no permit can be issued for land located within the Delta Primary Zone or any designated floodway. Contact the Yolo County Environmental Health Department for more information.

What Standards Must Be Met To Apply Biosolids To Land?

There are several requirements and restrictions that must be met by the applicator. Some of these requirements include:

Application is prohibited between November 15 and April 15. Water coming into contact with the land within 30 days of Biosolids application must be captured and disposed of on the application site.
Biosolids must meet specific pathogen and vector attraction reduction requirements, and chemical pollution limits.
Biosolids must be spread onto the land within 48 hours of arrival at the site, with few exceptions.
Biosolids staging areas must meet specific setback requirements from property lines, wells, roads, buildings, etc.
Application is prohibited where depth to groundwater is less than 5 feet, or where soils are saturated with water during periods of rainfall.
Biosolid application cannot create a nuisance condition.