In sewage treatment, sedimentation is divided into primary sedimentation and secondary sedimentation. The main structures for the first sedimentation are the primary sedimentation tank and the grit chamber, which are used to precipitate and remove suspended solids and gravel in the sewage, so as to avoid accumulation of the influent biological reaction tank, which leads to an increase in the inorganic content of sludge, which may lead to the biological reaction tank The sludge concentration is relatively high, and the organic content (MLVSS) is relatively low, which has an adverse effect on sewage treatment and sludge dewatering. Secondary sedimentation is usually called secondary sedimentation tanks, mainly amplitude-flow and vertical-flow sedimentation tanks. The function is to separate the sludge-water mixture in the biological reaction tank, realize sludge backflow, residual sludge discharge, and final effluent discharge.www.khnwatertreatment.com