选取北京市东城区北护城河某雨水排水口进行水质水量联合监测,分别识别了老城区在小雨、中雨、大雨3种不同雨型下的降雨径流污染特征,分析了初期冲刷效应和影响径流污染的敏感性指标及其阈值,制定了老城区源头和末端污染物管控方案.研究结果表明,降雨初期(小雨前20 min、中雨前30 min、大雨前10 min)污染物浓度较高,存在初期冲刷效应.小雨对SS、TP和TN指标的敏感性高于中雨和大雨,中雨对COD和NH3-N指标的敏感性高于小雨和大雨,中雨和小雨的EMC浓度值比大雨高.对于SS、NH3-N、TP指标,污染物浓度变化范围最大的分别为大雨、中雨、小雨.径流污染削减率为30％时,小雨、中雨和大雨需控制的降雨初期径流体积分别为25 m3、35 m3、150 m3,或控制降雨初期的降雨量为4 mm、9 mm、24 mm.
The characteristics of rainfall runoff pollution in the old urban area:A case study of a drainage district in Dongcheng District,Beijing
A rainwater outlet in the north moat of Dongcheng District of Beijing was selected for joint monito-ring of water quality and quantity,and the characteristics of rainfall runoff pollution in the old city under light rain,moderate rain and heavy rain were identified respectively.The initial scour effect and sensitivity indexes affecting runoff pollution and their thresholds were analyzed,and the control scheme of source and end pollu-tants in the old city was formulated.The results showed that the pollutant concentration was higher in the early period of rainfall(20 min before light rain,30 min before moderate rain,10 min before heavy rain),and there was an early scour effect.The sensitivity of light rain to SS,TP and TN is higher than that of moderate rain and heavy rain,the sensitivity of moderate rain to COD and NH3-N is higher than that of light rain and heavy rain,and the EMC concentration value of moderate rain and light rain is higher than that of heavy rain.For SS,NH3-N and TP indexes,heavy rain,moderate rain and light rain had the largest variation range of pollutant concentration.When the runoff pollution reduction rate is 30％,the runoff volume of light rain,moderate rain and heavy rain should be controlled to be 25 m3,35 m3 and 150 m3,or the rainfall in the early rainfall should be controlled to be 4 mm,9 mm and 24 mm respectively.
Beijingthe old cityrainfall runoffpollution characteristicsfirst flush
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