Current operation state of wastewater treatment plants in urban China

• Published in: Environmental research 2021-04, Vol.195, p.110843, Article 110843
• Main Authors: Zhang, Jingbing, Shao, Yuting, Wang, Hongchen, Liu, Guohua, Qi, Lu, Xu, Xianglong, Liu, Shuai
• Format: Article
• Language: English
• Subjects: Activated sludge; China; Energy and material consumption; Hydraulic loading rate; Operating conditions; Operational difficulties; Sewage - analysis; Waste Disposal, Fluid; Waste Water; Water Purification; WWTP
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2021.110843

Wastewater treatment plants (WWTPs) in urban China generally face operational difficulties. To comprehensively analyze the current operation status and determine the factors that caused difficulties in urban domestic WWTPs, we conducted a questionnaire survey, and 18 operating conditions of scale-level WWTPs in seven regions in China were investigated. The research results showed that, of the 467-urban domestic WWTPs surveyed in China, approximately 63.17% of the WWTPs' hydraulic loading rates (HLRs) are greater than 80%, 67.02% of the WWTPs have mixed liquor suspended solids (MLSS) concentrations greater than 4000 mg/L, and 95.93% of the WWTPs' mixed liquor volatile suspended solids to mixed liquor suspended solids (MLVSS/MLSS) ratios are lower than 0.7. The WWTP energy consumption accounts for approximately 1% of the national electricity consumption, and approximately 100,000 tons of various chemicals are consumed every year. A high HLR, a high activated sludge concentration and low sludge activity, design value mismatches with actual values, high energy and material consumption, etc. have become the main operational difficulties of urban domestic WWTPs. In this study, the main barriers that hinder improving the operating efficiency of WWTPs were investigated, the causes of operational dilemmas were analyzed, and pathways were jointly explored to solve them. This study may provide valuable implications for industry practitioners with a comprehensive grasp of the industry's current status and related policy formulation. •Current operation state of WWTPs in urban China was evaluated.•High HLR, Low MLVSS/MLSS, mismatch in design and actual, high energy consumption are main operation dilemmas.•Undeveloped sewers, inefficient treatment facilities, etc. were responsible for low efficiency of WWTPs.•The optimization of WWTP needs to start from the management of facilities and operation, establishment of supervision system.