Cao Y S, Tang J G, Henze M, Yang X P, Gan Y P, Li J, Kroiss H, van Loosdrecht M C M, Zhang Y, Daigger G T
41 Tian Jia Xian, Blk 6, 215006 Suzhou, China E-mail:
Shanghai Urban Construction, Design and Research Institute, No. 3447 Dong Fang Rd., 200125 Shanghai, China.
Water Sci Technol. 2019 Jan;79(2):334-341. doi: 10.2166/wst.2019.051.
China has achieved significant progress on wastewater treatment and aquatic environmental protection. However, leakage (in- and exfiltration) of sewer systems is still an issue. By using the statistical data of water and wastewater in 2016 in China, and the person loads (PLs) of water and wastewater in Singapore, the leakage fractions of hydraulic flow, organic carbon (COD), nitrogen (N) and phosphorus (P) mass loading, and in-sewer COD biological removal in the sewer systems of China (except Hong Kong, Macau and Taiwan), Shanghai, Guangzhou and Beijing were reported for the first time. The fractions of hydraulic flow infiltration (13%, Shanghai and Guangzhou) and exfiltration (39%, China) were calculated. Except Beijing, whose sewer networks are under appropriate management with small leakage fractions, the exfiltration fractions of COD (including in-sewer biological COD removal) ranged from 41% (Shanghai) to 66% (China) and averaged 55%; N ranged from 18% (Shanghai) to 48% (China) and averaged 33%; and P ranged from 23% (Shanghai and Guangzhou) to 44% (China) and averaged 30%. The exfiltrated sewage, COD, N and P not only wastes resources, but also contaminates the aquatic environment (especially groundwater) and contributes to 'black and odorous water bodies'. In- and exfiltration in the sewer network leads to low influent COD concentration, C/N ratio and high inorganic solids and inert particulate COD concentrations of many municipal wastewater treatment plants (WWTPs) causing high cost for nutrient removal, poor resource recovery, additional reactor/settler volume requirement and other operational problems. Therefore, tackling sewer leakage is of primary importance to today's environment in China. Recommendations for the inspection of sewer systems and the rehabilitation of damaged sewers as well as the development of design and operation guidelines of municipal WWTPs tailored to the specific local sewage characteristics and other conditions are proposed.
中国在污水处理和水环境保护方面取得了显著进展。然而，下水道系统的渗漏（包括内渗和外渗）仍是一个问题。利用2016年中国的水和废水统计数据以及新加坡的水和废水人均负荷，首次报告了中国（不包括香港、澳门和台湾）、上海、广州和北京下水道系统中水力流量、有机碳（化学需氧量，COD）、氮（N）和磷（P）质量负荷的渗漏率以及下水道内COD生物去除情况。计算了水力流量的内渗率（上海和广州为13%）和外渗率（中国为39%）。除北京的下水道网络管理得当、渗漏率较小外，COD的外渗率（包括下水道内生物COD去除）在41%（上海）至66%（中国）之间，平均为55%；N在18%（上海）至48%（中国）之间，平均为33%；P在23%（上海和广州）至44%（中国）之间，平均为30%。外渗的污水、COD、N和P不仅浪费资源，还污染水环境（尤其是地下水），并导致“黑臭水体”。下水道网络的内渗和外渗导致许多城市污水处理厂进水COD浓度、碳氮比低，无机固体和惰性颗粒COD浓度高，造成营养物去除成本高、资源回收差、需要额外的反应器/沉淀池体积以及其他运行问题。因此，解决下水道渗漏问题对当今中国的环境至关重要。本文提出了下水道系统检查、受损下水道修复的建议，以及针对当地特定污水特征和其他条件制定城市污水处理厂设计和运行指南的建议。
