Biosolids Definition

Biosolids means solid, semisolid, or liquid residues generated during primary, secondary, or advanced treatment of domestic sanitary sewage through one or more controlled processes that reduce pathogens and attractiveness to vectors (flies, mosquitos, rodents).  These processes include, among others, anaerobic digestion, aerobic digestion, and lime stabilization.  The term "Biosolids" is related to the definition of sewage sludge found in Part 31, Water Resources Protection of the Natural Resources and Environmental Protection Act, 1994 PA 451, as amended; however biosolids are only that portion of sewage sludge that have undergone adequate treatment to permit their application to land.  Rule 323.2405 of the Michigan Administrative Code excludes industrial sludge or septage from regulation as biosolids.