The production wastewater first enters the grid well, flows automatically to the regulating tank, is pumped into the phenol passivation equipment by the lifting pump, and undergoes drug phenol passivation decomposition treatment. After treatment, the water flows into the A/O secondary biological oxidation tank for deep biochemical treatment to achieve purification effect, and then flows into the sedimentation tank for secondary sedimentation. The clear water after sedimentation flows into the clear water tank through the drainage weir, and is filtered by the multi-media filtration equipment to meet the production reuse standard. The sludge at the bottom of the primary sedimentation tank and sedimentation tank is filtered by a sludge lift pump through a filter press, and the filtered sludge is squeezed into dry cakes for further processing;