Sewage by the Environmental Protection Agency. Because of the total amount or concentration of pollutants contained in high, sewage treatment plants are discharged from the source of pollution. Failure to meet the requirements of the discharge standards or do not meet the requirements of the environmental capacity, thereby reducing the quality of the water environment and functional objectives, it is necessary to go through artificial enhanced treatment of the site.
Generally divided into urban centralized sewage treatment plants and decentralized sewage treatment plants for each source of pollution.