Biosolids Program

What is a biosolid? Biosolids refer to the solid organic matter residuals generated by the biological wastewater treatment process. These residuals, or biosolids, contain essential nutrients that when properly treated and processed can be applied as fertilizer to farmland, improving soil health and fertility, and enhancing plant growth.

Why are biosolids important? Returning biosolids to farmland completes a natural food cycle where what farms produce is consumed by humans, who then produce biosolids, which - when treated appropriately to kill pathogens and enhance the fertilizer value - can then be returned back to the farms to offset costs and deliver remarkable results. This multi-use product can also be used for sod farming, soil remediation, horticulture and golf courses.

Nutrient-rich treated biofertilizer products include predictable nitrogen, phosphorous and potassium values as well as a variety of micronutrients such as iron, zinc, magnesium and copper, which are all essential for healthy agriculture soil and plant growth. In addition to rich nutrients, biosolids contain valuable organic matter which helps improve the overall health, structure and tilth of soil - which can't be replicated by synthetic, chemical fertilizers.

Class A Exceptional Quality Biosolids
To ensure maximum acceptability and safety, the City of Shelton treats biosolids to meet stringent standards imposed by the EPA for Class A Exceptional Quality (EQ) biosolids. The EPA-classified Class A (EQ) biosolids can be sold for commercial and residential use without any special permitting. In order to achieve this EQ standard, the City of Shelton uses the latest fertilizer manufacturing technology to heat treat the biosolids and eliminate all disease-causing bacteria.

The use of Class A EQ biosolids as fertilizer for both residential and commercial use is endorsed by the U.S. Environmental Protection Agency (EPA). The EPA promotes biosolid-based fertilizers as environmentally safe and beneficial for plant growth.

Regional Partnerships
As one of the only municipalities in the South Sound capable of producing Class A EQ biosolids, the City of Shelton has partnered with several local communities and businesses to process digested sewer sludge produced by other wastewater treatment facilities, including Mason County, Squaxin Island Tribe, Skokomish Tribe, Washington State Parks, Alderbrook Resort, City of Yelm and Thurston County.

Class A EQ biosolids are available for pickup, free of charge, at the City's Wastewater Treatment Plant, located at 1701 Fairmount Avenue in Shelton. Due to high demand, there is typically a 2-3 month waiting list. If you have questions or would like more information, please contact the Wastewater Treatment Plant at 360-426-6521.