Oily sewage from the dewatering station enters the high-water tank or the sewage sedimentation tank by the discharge pressure of the dewatering device or other containers. After natural sedimentation 2-3h, some oil droplets float up and gather.The sedimentation of sewage contains no more than 0.5% oil.It is pressurized by sewage pump and sent to oil removal tank.There are two kinds of oil tank removal: gravity type inclined plate removal oil tank and gravity type subsidence removal oil tank.After the oily water, the oil content should be less than 100mg/L, and the difference in liquid level between the oil tank and the filter tank is used to enter the gravity filter tank for filtration. The filtered water enters the clean water tank and is sent to the water injection station for reinjection by the external water pump.
The oil slick on the upper part of the subsidence tank and the oil slick on the oil removal tank received from the sewage tank, which was sent by the oil pump to the dewatering station for dewatering, ran treatment or as fuel.The gravity filter tank must be flushed back for a certain period of time. The water in the tank should be used to mill out the remaining oil in the filter layer to ensure the filtration capacity of the filter layer.The waste water after backwashing will flow into the underground recovery tank, which will be recycled by the lift pump and updated by the removal tank.