Applying Biosolids to Land in Michigan (E2780)
Biosolids are solid, semisolid and liquid residues generated during the treatment of sanitary sewage, or domestic sewage, in treatment works treating domestic sewage (TWTDS). The term was introduced by the wastewater treatment industry in 1991 to describe the residuals or solids created during the biological treatment of wastewater (hence “biosolids”). The wastewater treatment process that produces biosolids is schematically shown in Figure 1. The Michigan Department of Environmental Quality (MDEQ) has also adopted this term for rules made effective in November 1999.