Abstract:Taking the sewage system in the southern part of a city in the middle and lower reaches of the Yangtze River as an example, the issues such as external water intrusion, high water level operation and low concentration of sewage quality into WWTP are analyzed. The targeted ideas for improving the quality and efficiency by sections, zones and stages are proposed, and the technical measures for investigating the precipitation levels in sewage pipelines, renovating the municipal pipeline systems, renovating the drainage units and optimizing the operation of sewage pipeline network are put forward. Through the above measures, the extruded external water volume of 1# pumping station area initially implemented is approximately 12 708 m3/d, the concentration of BOD5 in the sewage into WWTP has been increased from 69.6 mg/L to 78.3 mg/L, improved by 12.5% compared with that before renovation, and the centralized collection rate of urban sewage has been increased from 61.6% to 69.3%, which basically realizes the stage goal of improving quality and efficiency.