Biosolid

Biosolid refers to the solid organic matter that results from the treatment of domestic sewage in a wastewater treatment plant. Through processes like sedimentation, digestion, and dewatering, the sludge is stabilized and its volume reduced. This treated material is often nutrient-rich, particularly in nitrogen and phosphorus, and can be recycled for beneficial purposes. The most common beneficial reuse is as a soil amendment or fertilizer in agricultural applications, where it improves soil structure and provides nutrients for plant growth. Biosolids can also be used in land reclamation projects, such as covering landfills or restoring disturbed land. However, the application of biosolids is regulated to ensure public health and environmental protection. Regulations typically address the pathogen content and the presence of contaminants like heavy metals to prevent harm. The term "biosolid" was introduced to distinguish this treated, beneficial material from raw, untreated sewage sludge, emphasizing its potential for recycling and reuse.