What is sludge (industrial waste)?
Sludge is a type of substance wherein suspended solids either settle or float in water to create muddy chunks. This type of industrial waste is generated through the course of water treatment process in various industrial activities. There are two types of sludge: organic sludge and inorganic sludge. The former is generated by treatment facilities that treat organic contamination in wastewater; for example, sewage, food production, paper-making and pulp mills. The latter type is generated by wastewater treatment facilities that treat wastewater containing high volumes of sand and metal components such as civil engineering sites, water purification plants, and metal plating plants.