北京城区不同下垫面降雨径流产污特征分析

通过对北京城区3类不同下垫面的降雨径流水质进行监测以及对实验数据进行皮尔森(Pearson)统计分析,探讨了沥青路面、硬质屋顶及草地屋顶的雨水径流污染物历时变化规律,计算了各场次降雨径流污染物的事件平均浓度(EMCs),分析了径流水质的主要影响因素.结果表明,相对于沥青路面与硬质屋顶,草地屋顶对除磷外的其他径流污染物浓度有明显削减作用;初期降雨径流中CODcr、NH3-N、NO3-N、TP、Pb、Cu、Zn的EMC值大多超出V类国家地表水标准,3类重金属污染物监测结果也表明城区暴雨径流污染明显;统计分析结果表明污染物质与前期晴天数、降雨历时呈现正相关关系,与降雨量、降雨强度呈现负相关关系,通过控制初期径流污染、加强清扫及屋顶绿化可以从源头减少城市降雨径流污染.

Pollution characterization of urban stormwater runoff on different underlying surface conditions

Based on monitoring the runoff water quality on different underlying surface conditions in Beijing and analyzing the experiment data via Pearson statistical method, the paper covered the time-varying regularity of stormwater runoff pollutants and the even mean concentrations (EMCs) of stormwater runoff pollutants. Major factors for runoff water quality were also analyzed. The results showed that compared with asphalt road and bituminous roof, the green roof had lower flush effect, playing an important role in reducing the concentration of runoff pollutants. The initial EMCs values of COD, NH3-N, NO3-N and TP were higher than the fifth category of national surface water standard. Parts of them were even beyond the third category of emission discharge standard. The values of EMCs were positively correlated with dry weather deposits and runoff duration, and negatively correlated with precipitation and rainfall intensity. The analysis indicated that the controlling preliminary runoff pollution and surface clean-up can reduce the urban rainfall runoff pollution.