Biosolids are the nutrient-rich organic materials resulting from the treatment of sewage sludge (the name for the solid, semisolid or liquid untreated residue generated during the treatment of domestic sewage in a treatment facility). When treated and processed, sewage sludge becomes biosolids which can be safely recycled and applied as fertilizer to sustainably improve and maintain productive soils and stimulate plant growth.

Only biosolids that meet the most stringent standards spelled out in the Federal and state rules can be approved for use as a fertilizer. Now, through a Voluntary Environmental Management System, being developed for biosolids (EMS) by the National Biosolids Partnership (NBP), community-friendly practices will also be followed.

Although cities decide how best to manage their biosolids, the U.S. Environmental Protection Agency (EPA) is obligated and continues to provide the public with educational information, based on the best science, about the safe recycling and disposal of biosolids. EPA strongly supports the ongoing efforts of the NBP to develop the EMS and to provide correct and timely information about biosolids via its new communications system.

Michigan's Biosolids Program
The Department of Environmental Quality (DEQ) encourages the use of Biosolids (also known as sewage sludge) to enhance agricultural and silvicultural production in Michigan. Almost all Biosolids that are land applied in Michigan are used to grow crops on sites at agronomic application rates approved by the DEQ. Biosolids are also used to provide nutrients and soil conditioning in mine reclamation programs, tree farms, and forest lands.