溶解态污染物是城市降雨径流污染的一个重要组成部分, 揭示其在降雨径流阶段的传输过程对于城市污水治 理具有重要意义。采用人工模拟降雨实验研究了不透水表面不同坡度( 01 5b、1b、2b、3b、4b、5b) 情况下降雨径流及溶 解态污染物传输过程。结果表明: 坡度越大, 坡面产汇流时间越短, 径流量越快达到稳定; 污染物浓度随降雨径流深 度增加呈逐渐减小趋势, 坡度越大, 初始浓度越高, 衰减越快; 污染物传输速率呈先增大后减小的变化规律, 坡度越 大, 污染物传输速率峰值越大, 峰值出现在径流深度为 01 3~ 01 5 mm 之间; 溶解态污染物传输过程符合指数冲刷模 型, 随着坡度的增大, 冲刷系数 k 先线性增加, 坡度大于 3b基本保持稳定。相对于颗粒态污染物, 溶解态污染物冲刷 系数大, 易被冲刷, 冲刷集中发生在径流初期。

Disso lved pollutants are an important pa rt o f urban rainfall r unoff po llut ion. T o r eveal their t ranspo rt pro cess during the rainfall r uno ff stage is of gr eat sig nificance to urban wastew ater t reatment. I n this study, w e conducted a series o f ex peri2 ments to study the pro cesses of r ainfall- runoff and dissolved pollutant tr ansport o ver imper vio us surface at different slopes ( 01 5b, 1b, 2b, 3b, 4b, 5b) . The results show ed that the hig her the surface slope, the sho rter the time of runoff yield and concentr a2 tion, and t he faster it to ok fo r the runoff volume to reach stability. T he po llutant concentr ation would decrease as the ra infall runo ff depth increased; the hig her the slope, the higher the initial concent ratio n, and t he faster the attenuation. T he pollutant transpo rt r ate wo uld incr ease first and then decrease with time; the hig her the slope, the larg er the peak o f pollutant transpo rt rate. T he peak of pollutant transpo rt r ate appeared when the cumulative runoff depth was 01 3 to 01 5 mm. T he pollutant trans2 port process co nfo rmed to the ex po nential wash2off model. The wash2off coefficient k w ould increase linearly f irst and then re2 main basically stable w hen the slo pe was abov e 3b. Com par ed w ith particulate po llutants, the disso lv ed po llutants had a lar ger was2off coefficient and wer e more likely to be washed o ff, especially in the initia l r unoff stag e.

国家重点研发计划( 2016YFC0402605) ; 国家自然科学基金项目( 51239003; 41323001) ; 江苏省第五期/ 333 工程0培养资金资助项 目( BRA2017371)