Biosolids projects

King County's Biosolids are recycled in a variety of ways throughout Washington State. We focus on finding beneficial and sustainable uses for our biosolids, typically partnering with landowners in large-scale projects. Currently, King County biosolids are trucked to our project sites, where they are used in forestry, agriculture, garden compost (GroCo) and landscape restoration. More information on our projects is available below.

 

	Dryland Wheat Farming - Boulder Park  This project encompasses several thousand acres of dryland grain crops in North Central Washington, where biosolids have proven to be highly beneficial for crop yield enhancement and reducing soil erosion. The Boulder Park project includes more than 100 landowners and farmers interested in improving their soils and enhancing the economy of their rural environment. Biosolids from other agencies are also recycled at this site, helping to satisfy the demand for this soil amendment.
	Natural Selection Farms - Yakima Valley  This project in the Yakima Valley includes farmers who are using biosolids to enhance soil fertility and to improve tilth and moisture retention. More than 35,000 acres of irrigated hops, canola, grain, and orchards and dryland pasture are available, with the capacity to recycle more than 50,000 tons of biosolids annually. Natural Selection Farms, Inc. is the local land application company formed by the local farmers.
	Forestry - Eastern King County  King County's forestry projects are part of a unique program to protect and enhance forests and wildlife habitat along the scenic I-90 corridor east of Seattle. Biosolids make an excellent soil amendment and source of nutrients for trees. In 1987, we began fertilizing plantations on the Snoqualmie Tree Farm in east King County. The Greenway Biosolids Forestry agreement expanded the program in 1995 to include state forests in the county. The nonprofit Mountains to Sound Greenway Trust initiated this program which now includes several public and private partners: the state Department of Natural Resources, King County, the Hancock Timber Resources and the University of Washington (UW).
	Biosolids Compost (GroCo) - Seattle  King County contracts with a local private company to make a biosolids compost which is marketed in the greater Seattle area as GroCo. Three parts sawdust and one part biosolids are blended and composted to create a fine-textured, exceptional quality biosolids product. Biosolids compost improves soils and provides plant nutrients.
	Research & Demonstration  Demonstrating plant quality and improved growth response has been a key to developing markets and revenue for biosolids. King County collaborates on research and demonstration projects with other biosolids managers who are members of the the Northwest Biosolids Management Association (NBMA). The NBMA funds scientists at the University of Washington, Washington State University, Oregon State University and University of Arizona. This program provides consistent information for biosolids managers and has enhanced our ability to create cost effective biosolids programs. An active research and demonstration program has improved both public awareness and acceptance of biosolids recycling.