The pre-treatment process of municipal wastewater treatment plant usually includes grating treatment, pumping pumping and sand sedimentation treatment. The purpose of grating treatment is to intercept the flow of large material to protect the subsequent pumping lines, the normal operation of the equipment. The purpose of pumping up the pumping station is to increase the head of water to ensure that sewage can flow by gravity through the subsequent treatment structures built on the ground. The purpose of sand treatment is to remove the sewage sand, stone and large particles, in order to reduce them in the subsequent structures in the settlement, to prevent the facility silt sand, affecting the effectiveness of the wear and tear caused by clogging, affecting the normal operation of the pipeline equipment. Primary treatment process: mainly primary sedimentation tank, the purpose is to remove the suspended solids in the sewage as much as possible settlement, the general initial sedimentation tank can remove about 50% of the suspended solids and 25% of the BOD5.
Secondary treatment
Mainly consists of the aeration tank and the secondary sedimentation tank, the use of aeration fans and special aeration devices to the aeration tank for oxygen supply, the main purpose of microbial metabolism of the sewage will be the main source of oxygen, the main purpose is to reduce the sewage in the aeration tank. The main purpose is to turn most of the pollutants in the sewage into CO2 and H2O through the metabolism of microorganisms, which is also known as oxygen consumption technology. Microorganisms in the aeration tank after the reaction with the water together with a steady flow into the secondary sedimentation tank, microorganisms sink to the bottom of the tank, and through the pipeline and pump back to the front of the aeration tank and the new inflow of sewage mixing; secondary sedimentation tank above the clarified water is a steady flow of treated water through the outlet weir out of the sewage plant.
Depth treatment: in order to meet the high standards of receiving water requirements or reuse for industrial and other special purposes and further treatment, the general process of coagulation and precipitation and filtration. The end of the depth of treatment often also have chlorination requirements and contact tanks. With the high level of urban socio-economic development, deep treatment is the need for future development.