The Oil Refining Wastewater Treatment Plant at Jinling Branch of Sinopec Corp was upgraded to meet strict water quality standards. The project improved the treatment of oily wastewater, reused water, and high-concentration wastewater. As a result, the treated water now meets the Jiangsu Provincial Discharge Standard for Chemical Industry pollutants. The levels of COD and NH3-N in the effluent are now below 60 mg/L and 15 mg/L respectively. The upgrade also enhanced the pre-treatment system and ensured the stable operation of the wastewater treatment plant, setting the stage for efficient wastewater reclamation and reuse.