城市机动车道路面初期效应及初期径流弃除量探讨

First Flush Effect and First Flush Discharge Volume of Urban Motorway Runoff

路面径流污染是城市面源污染的主要组成部分,初期径流弃除被认为是一种有效的源头控制方法。对于初期径流、初期效应尚没有明确的定义,且路面冲刷规律较难把握,使得对路面初期径流是否弃除以及弃除量的确定都缺乏理论依据。通过对北京某典型机动车道路面径流水质的监测,分别用基于浓度和基于负荷两种初期径流定义方法对初期效应进行了判断,初步得出路面径流的浓度初期效应不明显,污染负荷具有一定的初期效应,20%径流体积约可携带30%的污染负荷。根据对北京市30年降雨的统计分析,从尽可能收集较多的雨水进行利用及尽可能削减较多的污染负荷的考虑,建议采用4 mm降雨作为道路初期径流雨水的分离标准,可至少去除年均污染负荷的28.7%。研究结论和方法可为类似地区路面初期径流弃除量的确定及后续研究提供初步指导。

Road runoff pollution is a main part of urban non-point source pollution,and first flush discharging is considered to be an effective source control measure.As there is no clear definition of first flush and first flush effect,and road wash-off rule is difficult to understand,it＇s lack of theoretical basis on if road first flush should be discharged and how to determine its volume.Through monitoring road runoff quality in a typical motorway of Beijing,the first flush effect was analyzed based on concentration and pollution load respectively,and it preliminarily concluded that the pollution load had some first flush effect but concentration didn＇t,and 20% runoff volume carried about 30% pollution load.Through statistical analysis of Beijing rainfalls data of 30years,4mm precipitation was suggested for first flush removing volume of road runoff which could at least reduce pollution load by 28.7% annually,considering reusing rainwater and reducing pollution load as much as possible.The results and methods can provide primary guidance for the determination of road first flush removing volume in similar areas and subsequent research.