In December 2021, our company won the bid for the renovation project of the Huan Si Lian Wastewater Treatment Station in Liaohe Oilfield. Under the constraints of original structures, the project upgraded and reconstructed the wastewater treatment station. The two sets of Corrugated Plate Interceptors suffering from severe corrosion and structural collapse of internal components have been thoroughly rectified and upgraded. The thickened Fiber-Reinforced Plastic (FRP) anti-corrosion process was adopted to solve the corrosion problem of original on-site equipment. Meanwhile, our company's efficient Dissolved Air Flotation (DAF) unit replaced the original corroded flotation equipment, thereby enhancing treatment efficiency. The equipment was shipped to the site in May 2022. Although the project had complex construction and a tight schedule, our on-site construction personnel actively cooperated with the owner and the oilfield construction team, carried out reasonable division of labor and overlapping construction processes, and completed the project tasks on schedule.