中国城市污水处理的瓶颈, 缘由及可能的解决方案

Since about the 1990s China has achieved remarkable progress in urban sanitation. The country has built very extensive infrastructure for wastewater collection and treatment, with 94.5% coverage in urban areas and legally mandated nation-wide full nutrient removal implemented. However, municipal wastewater treatment plants (WWTPs) in China are still confronted with several bottlenecks rooted in the unique sewage characteristics, which are caused by leakage of sewer systems. This study compared energy recovery, cost of nutrient removal and sludge production between Chinese municipal WWTPs and those in countries with longer wastewater treatment traditions, and, on the basis of theoretical analysis, highlighted the cause-effect relationships between Chinese sewage characteristics, including high inorganic suspended solids (ISS) loads, low COD, and low ρ(C)/ρ(N) and municipal WWTP process performance in China. It proposes that China needs to develop guidelines for the design of urban wastewater treatment processes based on its own unique wastewater quality characteristics. In view of the time-consuming construction and rehabilitation of sewer systems, the improvement of the efficiency and sustainability of existing urban sewage treatment plants should be promoted simultaneously with sewer rehabilitation and design guidelines. To this end, cost-effective technical measures and solutions need to be selected and implemented. This paper proposed to strengthen work in three areas: improving the efficiency of grit removal, applying sludge fermentation and anaerobic digestion, and optimizing the existing and developing low-carbon biological nitrogen removal processes, and estimated the potential benefits of implementing these technical measures. The necessity of strengthening the application research of municipal sewage treatment oriented to the improvement of engineering applications was emphasized.