Biosolids are the organic residuals produced during wastewater treatment. An IASP biosolids composting study was performed at Central Valley in Salt Lake City, Utah in October 2006.

Once composted, biosolids look like other commercially available composts and are approved for use by the U.S. Environmental Protection Agency as a soil amendment by home gardeners, farmers and others. Biosolids provide soils with the nutrients that tend to be deficient. These products are used in landscaping and gardening in the following ways:

• As a fertilizer: Biosolids products improve plant vigor by adding nitrogen, phosphorus and other nutrients to soils. Biosolids reduce the amount of synthetic fertilizers required because they release nutrients as plants need them.

• As a soil amendment: Composts and other biosolids products available for public use improve the physical characteristics of the soil. Compact and clay-like soils are made lighter and more porous; sandy soils benefit from improved water retention.

• As a mulch: The addition of biosolids compost as a mulch reduces watering requirements, inhibits weed intrusion and adds beauty to the landscape.
  As a potting medium: When mixed with potting soil, biosolids products provide an ideal medium for potted plants and greenhouse containers. Biosolids compost makes an excellent substitute for manure composts, peat moss and other components of typical soil mixes.