Systematic Governance Framework for Quality and Efficiency Improvement of Sewage Pipeline Networks in Rainy Cities of Southern China
To address the decline in operational performance of sewage pipeline networks in rainy cities of southern China caused by structural defects, stormwater-sewage cross-connections, and external water intrusion, a systematic governance framework comprising precise investigation, dynamic regulation, graded rehabilitation, and smart operation and maintenance was established. A zoned priority evaluation model was developed with comprehensive problem severity (P) and governance contribution (B) as core indicators, based on which differentiated governance strategies were formulated. Supported by a digital platform, monitoring, assessment, rectification, and verification data were integrated to develop a digital twin system for the pipeline network, and a correlation-based analysis and closed-loop operation and maintenance mechanism linking rainfall, groundwater level, and network hydraulic load was established. A typical urban area in Jiangxi Province was selected as the case study. After implementation, the mean COD concentration of terminal sewage in the study area increased steadily to above 230 mg/L, the average daily external water volume in the dry season decreased by 27.64%, and the sewage collection rate increased to 76%. The results indicate that the proposed framework can effectively support the quality and efficiency improvement of sewage pipeline networks in rainy cities of southern China, and provide a technical reference for similar cities.