Sewage treatment is the process of removing contaminants from municipal wastewater, containing mainly household sewage plus some industrial wastewater. Physical, chemical, and biological processes are used to remove contaminants and produce treated wastewater that is safe enough for release into the environment. Sewage treatment is the process of removing contaminants from wastewater and household sewage water. Click here for our range of sewage treatment plants. Its aim is to produce an environmentally safe sewage water, called effluent, and a solid waste, called sludge or bio solids, suitable for disposal or reuse.