A wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water pollution from raw sewage discharges. Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water pollution. Typical pipe materials for small diameter sanitary sewers (8″ through 24″ diameter) include PVC, vitrified clay, and ductile iron. Our goal of wastewater treatment facilities is to protect people, as well as local ecosystems, from toxic elements found in wastewater. Water treatment facilities were designed to speed up the natural process of purifying water.  Our objective of sewage treatment is to remove solids and to reduce its biochemical oxygen demand (BOD) before returning the treated wastewater to the environment. Sewage sludge, increasingly referred to as biosolids, is an inevitable product of wastewater treatment.