成都市中心城区非渗透下垫面降雨径流污染物特性研究

Study on Pollutant Characteristics of Rainfall and Runoff in Non-permeable Underlying Surface in Central Urban Area of Chengdu

为进一步分析成都市中心城区河流受降雨径流面源污染的影响,在2016年和2017年共监测了8场次降雨事件,结果发现:(1)成都市中心城区非渗透性下垫面径流中的COD和TN浓度基本高于地表V类水质标准; TP高于Ⅲ类水质标准的频次为41. 8%,重金属指标基本在地表Ⅲ类水以内,近年来成都市中心城区降雨径流面源污染有所缓解,但污染程度总体与上海市近似,但显著高于美国大中城市监测结果;(2)除屋顶外(<30%),各下垫面固液分配比例基本表现出初期的颗粒态冲刷效应。马路和小区路面TP颗粒态比例大于50%,COD颗粒态比例为60%左右;(3)相关性分析表明,颗粒态物质是降雨径流污染物的重要来源,且大多源于有机耗氧物质。

In order to analyze the impact of runoff pollution on urban river water quality in Chengdu,8 rainfall events were monitored in 2016 and 2017.The results showed that(1)COD and TN concentrations in runoff in non-permeable underlying suifacein Chengdu urban area were mostly higher than V level of environmental quality standards for surface water.The frequency of TP concentration that exceeds III level of surface water quality was 41.8%.And heavy metals concentrations were almost under III level of surface water quality.In recent years,the non-point source pollution of rainfall and runoff in the central urban area of Chengdu has been alleviated,but the pollution degree is generally similar to that of Shanghai,but significantly higher than that of large and medium-sized cities in the United States.(2)Except for roof runoff(<30%),the solid-liquid distribution ratio of each underlying surface showed the initial particle state scouring effect.Particle TP proportion was>50%,particle COD proportion was about 60%.(3)The correlation analysis showed that particulate matter is the important source of pollutant in rainfall runoff,and mostly comes from organic oxygen consumption.