ABSTRACT
The United States Environmental Protection Agency accepts the term biosolid for sewage sludge that is treated to meet the regulations in 40CFR503. Moreover, the term sludge is used for many different materials, both inorganic and organic. A better term would be sewage biosolids, because it indicates the biological nature of the residual and its origin. Biosolids are derived from the treatment of wastewater. The wastewater, primarily derived from domestic sources, is treated at a publicly owned treatment works. In the United States there are vast differences in the way biosolids or sewage sludge is utilized or disposed. Direct land application can be beneficially used in agriculture, forestry, and land reclamation. Direct land application for beneficial use involves some form of partial stabilization such as digestion or alkaline stabilization. Biosolids compost is primarily used as a soil amendment and is valued for the organic matter content.
