The Department of Environmental Quality (DEQ) encourages the use of  Biosolids (also known as sewage sludge) to enhance agricultural production in Michigan. Almost all Biosolids that are recycled in Michigan are land applied at agronomic application rates to grow crops on sites approved by the DEQ. Biosolids applications are controlled by Residuals Management Programs (RMPs) that are required by the provisions of a facility's National Pollutant Discharge Elimination System (NPDES) discharge permit for wastewater treatment or by a general permit.