Current state of sewage treatment in China

• Published in: Water research (Oxford) Vol. 66; pp. 85 - 98
• Main Authors: Jin, Lingyun, Zhang, Guangming, Tian, Huifang
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2014; Elsevier
• Subjects: Applied sciences; Biological and medical sciences; Biological Oxygen Demand Analysis; Biological treatment of waters; Bioreactors - microbiology; Biotechnology; Environment and pollution; Exact sciences and technology; Existing problems; Fundamental and applied biological sciences. Psychology; Future development; Geographical distribution; Industrial applications and implications. Economical aspects; Other wastewaters; Pollution; Scale; Sewage - microbiology; Treatment process; Waste Disposal, Fluid - methods; Wastewater treatment plants; Wastewaters; Water Purification - methods; Water treatment and pollution; Asia; China; Geographical distribution; Scale; Treatment process; Future development; Wastewater treatment plants; Existing problems; Water treatment; Geographic distribution; Urban waste water; Waste water purification; Sewage treatment plant; Biological purification
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2014.08.014

The study reported and analyzed the current state of wastewater treatment plants (WWTPs) in urban China from the aspects of scale, treatment processes, sludge handling, geographical distribution, and discharge standards. By 2012, there were 3340 WWTPs in operation in China with a capacity of 1.42 × 108 m3/d. The number of medium-scale WWTPs (1–10 × 104 m3/d) counted for 75% of total WWTPs. On average, the chemical oxygen demand (COD) removal efficiencies of small-scale, medium-scale, large-scale and super-large-scale WWTPs were 81, 85.5, 87.5 and 86.5%, respectively. Generally speaking, the nutrients removal instead of COD removal was of concern. As to the different processes, oxidation ditch, anaerobic–anoxic–oxic (A2/O) and sequencing batch reactor (SBR) were the mainstream technologies in China. These technologies had minor difference in terms of overall COD removal efficiency. The sludge treatment in WWTPs was basically “thickening-coagulation-mechanical dehydration” and the major disposal method was sanitary landfill in China. The distributions of WWTPs and their utilization showed significant regional characteristics. The sewage treatment capacity of China concentrated on the coastal areas and middle reaches of Yangtze River, which were the economically developed zones. Besides, most WWTPs enforced the Class 1 or Class 2 discharge standards, but few realized wastewater reuse. Finally, existing problems were discussed, including low removal efficiency of nitrogen and phosphorus, emerging contaminants, low reuse of reclaimed water, poor sludge treatment and disposal, low execution standard of effluent, and emissions of greenhouse gas from WWTPs. Suggestions regarding potential technical and administrative measures were given. [Display omitted] •Fully reported and analyzed the current state of sewage treatment in China.•Systematically summarized the existing problems of sewage treatment in China.•Detailed advices on corresponding technical and administrative methods were given.