上海市排水系统雨天出流的初期效应分析

Analysis on the First Flush Effect of Stormwater Discharge from Shanghai Drainage System

以上海市苏州河沿岸5个代表性排水系统为研究对象,采用无因次累积负荷体积分数曲线[M(V)曲线]和b参数方法,对上海市排水系统雨天出流的初期效应现象进行了探讨。研究表明,若以30/80标准衡量,5个排水区域都没有初期效应。若以50/50标准判定,合流制系统具有微弱初期效应,分流制系统雨天出流水质变化过程随降雨事件不同而有很大波动,总体上没有初期效应。COD和BOD5比SS更具初期效应。各水质指标的初期效应强度随不透水比例增加而增加,随汇水面积增加而减小。研究成果为雨水存储池等城市面源污染控制设施的规划设计提供了依据。

Study was made on five typical drainage systems along the Suzhou Creek. The dimensionless accumulative mass loading vs. volume curve [M（V） curve] and parameter b were used to discuss the first flush effect of storm water discharge from Shanghai drainage systems. The result shows that there is no first flush effect in the five systems according to the standard of 30/80 ; while according to 50/ 50, little first flush effect is observed in the combined system; and in the separate system, the discharged stormwater quality is varied greatly with the storm events and no first flush effect exists in general. COD and BOD have stronger first flush effect than SS. The strength of first flush effect is increased with the increased proportion of impervious area and is decreased with the increased catchment area. The above findings provide the basis for the planning and design for the non-point pollution control facilities including stormwater storage tank and so on.