中国城市污水处理的瓶颈、缘由及可能的解决方案

Bottlenecks and Causes,and Potential Solutions for Municipal Sewage Treatment in China

自20世纪90年代以来,中国在城市污水收集与处理方面取得了很大的进步.但是,源自于独特污水水质特征,中国城市污水处理效率的改善仍然面临瓶颈.该文着重比较了中国和其他国家的城市污水处理在能量回收、氮磷营养物去除和污泥产率方面的差异,并在资料支撑的理论分析基础上,揭示了因为下水道渗漏、化粪池设置等因素导致的中国城市污水独特的水质特征(高无机悬浮固体(inorganic suspended solids,ISS)质量浓度、低碳氧需求(COD)和低碳氮比)与城市污水处理厂较低的运营效率和性能之间的关系,提出了中国需要制定适合自己独特污水水质特性的处理过程设计指南.鉴于下水道系统建设与修复耗时长久,改善现有城市污水处理厂的效率和可持续性应该与下水道修复和制定设计指南同时推进,提出了三点建议:提高除砂效率、应用污泥发酵和厌氧消化、优化现有工艺并开发低碳源生物脱氮新工艺.

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 lowρ(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.