城镇污水处理提质增效的内涵与思路

Connotation and Thinking of Improving Quality and Effi ciency of Urban Sewage Treatment

城市污水管网中在干旱季节高温度、低流量时产生的细颗粒物沉降是我国城市特有的环境现象,也是城镇污水处理厂进水污染物含量明显过低,碳、氮、磷比值明显下降的根本原因。入渗/入流到城市污水管线中的大清水、小强度污水排口拦截方式,以及直接进入城市雨水管线中或通过末端截流方式进入城市污水管网中的施工雨水及基坑排水方式,是我国城镇污水处理厂在干旱时节进水水质污染物含量明显偏低、处理效率较低的主要根源。在雨季,大量雨水直接进入城市污水管线和合流制管网中,并带入大量沉积物,直接侵蚀城区水体,是城市水体污染及雨后黑臭、底泥现象不能完全消除的主要原因,也是我国大部分城区“生活污染集中收集利用率”偏低的最直接原因。本文针对贵州全省城乡污水处理提质增效项目的开展现状,在污水处理的质量监测、收集设施效果评价、雨污管网建设和技术改造、城市雨水污染管理和工业污水控制等方面提出了重点操作目标,并探索了当前处理城乡用水环境生态矛盾、实现提质增效最实际、最可行的方法。

The sedimentation of fine particles in the urban sewage pipe network at high temperature and low flow in the dry season is a unique environmental phenomenon in China’s cities,and it is also the fundamental reason for the significantly low content of pollutants in the influent water of urban sewage treatment plants and the significant decline in the ratio of carbon,nitrogen and phosphorus.The intercepting method of large clean water and small strength sewage outlets in the infiltration/inflow urban sewage pipeline,and the construction rainwater and foundation pit drainage method that directly enter the urban rainwater pipeline or enter the urban sewage pipe network through the end intercepting method,are the main reasons why the content of water pollutants entering the urban sewage treatment plants in China during the dry season is significantly low and the treatment capacity is far more than the wastewater capacity.During the rainy season,a large amount of rainwater directly enters the urban sewage pipeline and the combined pipe network,and directly erodes or brings a large amount of sediment into the urban water body during the dry season,which is an important reason that the ash,odor and sediment phenomenon of urban water pollution cannot be completely eliminated after the rain,and is also the most direct reason for the low“centralized collection and utilization rate of domestic pollution”in most urban areas of China.In view of the current situation of the project of improving the quality and economic efficiency of urban and rural sewage treatment in the province,the most important operational objectives are given in terms of the quality monitoring of sewage treatment,the evaluation of the effect of collection facilities,the construction and technical transformation of rainwater and sewage pipe network,urban rainwater pollution management and industrial sewage control,and the most practical and feasible methods to deal with the ecological contradictions of urban and rural water environment and achieve the improvement of quality and economic efficiency are explored.