Sewage treatment is the process of removing contaminants from wastewater and household sewage, domestic, commercial and institutional. Sewage treatment includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants. Sewage treatment produces an environmentally safe fluid waste stream and a solid waste suitable for disposal or reuse, usually as farm fertiliser. Sewage is generated by residential, institutional, commercial and industrial establishments, such as household waste from toilets, baths, kitchens and sinks. Sewage also includes liquid waste from industry and commerce.