Key Takeaways & Executive Findings
- •• • The zoned priority evaluation model, integrating structural defect density, cross-connection density, and pollution load, enables identification of high-risk zones, achieving a 27.64% reduction in dry-season external water inflow and raising terminal COD to above 230 mg/L. • • Full-chain governance, including over 42 km of structural renewal and rehabilitation and 3,552 cross-connection rectifications, improved sewage collection rate to 76%, demonstrating system-level efficacy. • • The smart O&M platform, with digital twin and closed-loop mechanisms, supports sustained performance by integrating monitoring, assessment, and rectification data, crucial for long-term operational stability. • • The framework's effectiveness in a rainy southern city validates its scalability, offering a replicable model for similar urban areas facing infiltration and inflow challenges.
Abstract
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.
1. Introduction
Urban sewage systems in rainy southern China suffer from chronic inefficiencies due to structural defects, illicit connections, and external water intrusion, exacerbated by high groundwater levels and abundant rainfall. Traditional approaches, focusing on point-source repairs, fail to address systemic interactions, leading to diluted influent, increased energy costs, and unmet pollution reduction targets. The industry lacks a decision-making framework to prioritize interventions under resource constraints.
This study introduces a systematic governance framework that integrates precise investigation, dynamic regulation, graded rehabilitation, and smart operation and maintenance. By developing a zoned priority model based on problem severity and governance contribution, and leveraging digital twin technology, the framework enables targeted, data-driven interventions. Case study results demonstrate significant improvements in effluent quality and inflow reduction, providing a robust solution for similar urban environments.
Loading authentic research manuscript (Pages 1–5)...
HAN Yuan, GUO Junting, SONG Shengnan, ZHANG Xianguo, WANG Zhengshu, FU Xitong (2026). Systematic Governance Framework for Quality and Efficiency Improvement of Sewage Pipeline Networks in Rainy Cities of Southern China. Journal of Environmental Engineering Technology. https://doi.org/10.13205/j.hjgc.202605004
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
How does the zoned priority model handle data uncertainty from heterogeneous sources?
The model integrates multiple indicators (structural defect density, cross-connection density, pollution load) into composite scores P and B. While the paper does not detail uncertainty quantification, the framework's reliance on comprehensive monitoring and digital twin suggests iterative calibration. For robust application, sensitivity analysis and probabilistic methods should be incorporated.
What are the scalability challenges when applying this framework to larger or different geographic contexts?
The framework's modular design allows adaptation, but scalability depends on data availability and infrastructure. In larger networks, the cost of CCTV inspection and monitoring may increase. However, the digital twin and closed-loop O&M can prioritize high-risk zones, optimizing resource allocation. Transferability to other rainy cities requires calibration of model parameters to local conditions.
How does the framework ensure long-term performance beyond the initial rehabilitation?
The smart O&M platform establishes a closed-loop mechanism with monitoring, early warning, work order management, and effect evaluation. Continuous data collection and analysis enable proactive maintenance, preventing recurrence of defects. The paper suggests further research on multi-source data fusion and dynamic regulation to enhance long-term stability.
What are the cost implications of implementing this framework compared to traditional methods?
The paper does not provide a cost-benefit analysis. However, by prioritizing high-impact zones and using digital tools, the framework likely reduces overall expenditure by avoiding unnecessary repairs and optimizing resource use. The 27.64% reduction in external water and improved COD levels indicate operational savings from reduced treatment loads.
How does the framework address combined sewer overflows during heavy rainfall?
The framework includes dynamic regulation and correlation analysis linking rainfall, groundwater, and network load. This enables real-time adjustments to mitigate overflow risks. The case study shows improved dry-season performance; wet-season performance is not detailed, but the digital twin can simulate scenarios to optimize storage and treatment.
Related Chinese Research & Cross-Citations
Synergistic Regulation by Long- and Short-Chain Quorum Sensing Signaling Molecules Enhances Sulfamethoxazole Metabolism in Electroactive Biofilms within a Microbial Electrolysis Cell Coupled Anaerobic Digestion System
High-strength sulfamethoxazole (SMX) wastewater severely inhibits anaerobic microorganisms, reducing organic degradation and methane yield. This study investigated the effects of short-chain (C6-HSL) and long-chain (C12-HSL) N-acyl-homoserine lactone (AHL) signaling molecules, individually and in combination, on the construction, performance, and antibiotic resistance gene (ARG) profiles of anaerobic electroactive biofilms within a microbial electrolysis cell coupled anaerobic digestion (MEC-AD) system. Compared to the control (no AHLs), SMX removal efficiency increased by 9.26%, 7.44%, and 10.67% for C6-HSL (T1), C12-HSL (T2), and combined (T3) treatments, respectively. Methane production rates rose by 20.4%, 16.9%, and 23.1% for T1, T2, and T3, respectively. AHLs promoted extracellular polymeric substance secretion, enhancing electroactive microbe attachment to the anode. Microbial community analysis revealed increased diversity and modulated key functional genera. Notably, Georgenia abundance increased by 16.77% (T1) and 36.47% (T3) but decreased by 15.99% (T2). ARG analysis showed that single AHLs elevated intI1, sul1, and sul2 abundances, whereas combined AHLs (T3) exhibited a milder response, with sul2 abundance reduced by 4.92% relative to control. This suggests synergistic AHLs suppress ARG host proliferation. This study first demonstrates that combined short- and long-chain AHLs enhance electroactive biofilm formation, maintain microbial community stability, and modulate ARG dissemination risk, offering a quorum sensing-based strategy for antibiotic wastewater treatment and risk management.
Preparation of Solid-Phase Carbon Sources with Different Ratios and Their Carbon Release Properties
Low C/N ratios in wastewater treatment plant effluent necessitate external carbon sources for denitrification, but conventional liquid carbon sources are costly and unstable. This study prepared nine composite solid-phase carbon sources by combining PHBV with natural cellulose materials (straw, sawdust, corncob) at different mass ratios. Dynamic release experiments, DOC analysis, UV-Vis spectroscopy, and EEM fluorescence were employed to characterize carbon release. Results showed that increasing cellulose proportion in corncob-based sources led to release patterns opposite to those of straw- and sawdust-based sources. For straw and sawdust, higher cellulose ratios accelerated release rates, increased total release and duration, reduced aromaticity and molecular weight of released DOM, and promoted protein-like components (tryptophan, tyrosine), indicating enhanced bioavailability. Under identical ratios, corncob-based sources exhibited moderate total release, release durations exceeding 134 h, lower DOM aromaticity and molecular weight, and lower humic substance proportion, indicating superior bioavailability and engineering potential. Among the nine sources, JG5, MX5, and CC4 (PHBV:cellulose mass ratios of 4:5, 4:5, and 1:1, respectively) showed optimal comprehensive performance with low theoretical maximum release, long release periods, and high mass transfer coefficients. EEM-PARAFAC identified three DOM components (protein-like C1, C2; humic-like C3), with protein-like components dominating. This study validates the relationship between cellulose proportion and release kinetics and reveals synergistic regulation of DOM components, offering guidance for designing effective solid-phase carbon sources.
Enhancement of Anaerobic Digestion Operational Efficiency for Guar Gum Production Wastewater Using a Microaerobic-Biochar Coupled System
Guar gum production wastewater contains 1,2-propanediol, which in conventional anaerobic treatment causes propionate accumulation and microbial inhibition. Microaerobic conditions foster fermentative bacterial metabolism, enhancing organic substrate conversion, while biochar promotes anaerobic microbial aggregation and oxygen tolerance. This study treated actual guar gum wastewater using three configurations: blank control, anaerobic, and microaerobic-biochar (O2/BC) coupled systems. Under mesophilic conditions (37 °C), with micro-aeration at 0.2 mL/(g VS·d) and biochar dosage of 15 g/L, the O2/BC system achieved a COD removal efficiency of 90%, 10.6 percentage points higher than the anaerobic control. Effluent COD and propionate concentrations dropped to 3800 mg/L and 0.15 g/L, respectively, representing reductions of 49.6% and 98.4% versus the control. Biogas production was 1.64 times that of the control, with a maximum methane concentration of 77.2%. Fourier transform infrared spectroscopy (FT-IR) indicated increased abundance of –OH, –CH2–, and C–O functional groups on sludge surfaces, revealing biochar's adsorption enhancement. Scanning electron microscopy (SEM) showed dense microbial aggregates dominated by long bacilli, distinct from conventional anaerobic sludge. Microbial community analysis revealed increased abundance of Clostridium and Comamonas, modulating the propionate-to-acetate ratio and optimizing acidification efficiency, thereby promoting complex organic degradation. This study provides a novel technical pathway for biological treatment of alcohol-rich organic wastewater.
Occurrence Characteristics, Source Apportionment, and Ecological Risk Assessment of Pesticides in Plateau Lakes: A Case Study of Dianchi Lake
This study systematically investigated the occurrence, spatial distribution, sources, and ecological risks of 160 pesticides in Dianchi Lake, a typical plateau lake impacted by agricultural activities. A total of 37 pesticides were detected in the water, with total concentrations ranging from 64.2 to 1132.8 ng/L (average 610.0 ng/L). Fungicides, including boscalid (BOS), fluopicolide (FPC), and dimethomorph (DMM), were dominant, contributing up to 65.0% of the total concentration. Spatially, the southern lake region exhibited significantly higher concentrations (672.5 ng/L) than the north, attributed to intensive facility agriculture. Highly hydrophobic pesticides, such as penconazole (PEN), showed a tendency to enrich in bottom layers. Source apportionment identified inflowing rivers and wastewater treatment plant effluents as primary input sources, with average concentrations 7 and 9 times higher than lake water, respectively. Ecological risk assessment revealed that pesticides posed the highest risk to algae, followed by daphnia and fish. Prometryn (PMT) was identified as a high-risk factor for algae, while profenofos (PFF) and carbendazim (CBD) posed potential threats to higher trophic levels. These findings provide fundamental data and technical support for understanding pesticide pollution in plateau lake ecosystems.
Microbiome Mechanisms of Composite Carbon Sources for Enhancing Denitrification and Reducing N2O Emissions
Biological nitrogen removal in wastewater treatment plants (WWTPs) is often limited by insufficient influent carbon sources, necessitating external carbon addition to enhance denitrification. Conventional single carbon sources, such as sodium acetate, frequently fail to meet the metabolic demands of complex microbial communities, compromising nitrogen removal efficiency and stability. Composite carbon sources, by providing multiple electron donors, can improve metabolic cooperation among microorganisms, yet their underlying microbial mechanisms remain insufficiently understood. In this study, activated sludge from a municipal WWTP was used to investigate the microbial mechanisms of composite carbon sources during denitrification. Batch denitrification experiments were conducted in combination with metagenomic and metatranscriptomic analyses to systematically characterize microbial community structure and functional gene expression under different carbon source conditions. Results showed that, compared with sodium acetate as the single carbon source, the composite carbon source system (sodium acetate: sodium succinate: ethanol = 2:1:3) increased the denitrification rate from (6.822 ± 0.141) mg/(L·h) to (8.370 ± 0.186) mg/(L·h), representing a 22.7% improvement, while reducing N2O accumulation by approximately 55%. Metagenomic analysis revealed that Ottowia, Rubrivivax, Thauera, and Zoogloea were the dominant denitrifying genera. Metatranscriptomic results further demonstrated that the composite carbon sources significantly upregulated the transcription of key denitrification genes, with nirS, norB, and nosZ increasing by 37.8%, 27.4%, and 48.6%, respectively. In addition, the composite carbon sources promoted complementary carbon metabolic strategies among different microbial communities, enhancing electron donor supply and improving denitrification efficiency. These findings indicate that composite carbon sources synergistically enhance denitrification performance through regulation of functional gene transcription in complex microbial communities, providing a theoretical basis for carbon source optimization in WWTPs.
Key Environmental Behaviors and Pollution Control Strategies of Tire Wear Particles in Aquatic Environments
Tire wear particles (TWPs) are emerging pollutants and constitute the dominant type of microplastics (MPs) in urban stormwater runoff, accounting for up to 90% of MPs in some cases. They are characterized by small size, high mobility, complex composition, and significant toxicity. Current research on TWPs remains fragmented, lacking a comprehensive understanding of their environmental behaviors and pollution control in aquatic systems. This review systematically analyzes the enrichment and vectoring roles of TWPs for coexisting pollutants, and their environmental fate, including ecotoxicological impacts, detection methodologies, release of intrinsic additives, and aggregation and sedimentation behaviors. Drawing on insights from other microplastic studies, the paper explores control technologies across the pollution pathway—source, transport, and terminal treatment—and proposes feasible management strategies. Key findings indicate that TWPs can adsorb heavy metals and organic contaminants, with adsorption capacities influenced by aging processes. Their aggregation is governed by solution chemistry, with critical coagulation concentrations varying with ionic strength and pH. The release of additives such as zinc and benzothiazoles is significant, posing ecological risks. Future research should focus on real-water aggregation mechanisms, additive release under natural conditions, long-term performance of treatment facilities like constructed wetlands under TWPs stress, enzymatic degradation pathways, and integration of AI, big data, and IoT for cost-effective detection and risk modeling. This review provides a scientific basis for developing targeted pollution control measures for TWPs in aquatic environments.