According to the characteristics of grain and oil processing oil wastewater, our company adopts the treatment process of "oil separation + air flotation" to remove suspended oil from oil separation, followed by air flotation to remove emulsified oil; The "hydrolysis +AO" process is adopted to reduce the pollutants in the wastewater, and the coagulation-precipitation process is adopted in the final depth to ensure that the wastewater treatment meets the discharge standards. The effluent can reach the following indexes: CODcr≤100mg/l, BOD5≤30mg/l, SS≤20mg/l, NH3-N≤15mg/l, TN≤25mg/l, TP≤1.0mg/l.