合流制溢流控制指标与标准制定研究

Study on control indicators and standard formulation of combined sewer overflow

合流制溢流(combined sewer overflow,CSO)控制是城市水环境质量改善的关键一环,相关指标及标准制定尚显薄弱。基于技术的排放控制指标主要包括溢流频次、溢流体积控制率、污染物排放浓度限值、CSO效率及稀释度等,因这些指标缺乏对CSO水质水量控制效果的综合评价,进而提出雨季CSO污染负荷占比的指标;基于受纳水体水质保障的控制指标包括急性氨中毒、溶解氧浓度及细菌标准等。总结CSO控制标准确定依据,主要分为类比分流制污染负荷确定CSO污染物排放标准、依据工程实践效果制定CSO效果标准以及依据水体用途对CSO制定不同控制水平的标准。在此基础上,提出在“摸清本底,明确目标,系统治理”的理念指导下构建以受纳水体水质达标为目标导向的CSO控制标准体系及治理技术路线,为我国CSO标准制定提供参考。

The control of combined sewer overflow(CSO)is a key part of improving the quality of urban water environment,and the related indicators and the formulation of standards are still weak.Technology-based emission control indicators mainly include overflow frequency,overflow volume capture rate,pollutant emission concentration limit,CSO efficiency and dilution,etc.Due to the lack of comprehensive evaluation of these indicators on CSO water quality and quantity control effect,the index of CSO pollution load proportion in rainy season is proposed.The control indexes based on the water quality assurance of receiving water include acute ammonia poisoning,dissolved oxygen concentration and bacterial standard,etc.This paper summarizes the basis for determining the CSO control standard,which is mainly divided into three parts:determining the CSO pollutant discharge standard by analogy with separate sewer system pollution load,establishing the CSO effect standard according to engineering practice effect,formulating different control levels of CSO according to the use of water body.On this basis,under the guidance of the concept of“finding out the background,making clear the goal,and systematic treatment”,the CSO control standard system and treatment technology route with the goal of meeting the water quality standard of receiving water body are proposed to provide reference for the formulation of CSO standards in China.