山地城市径流污染特征分析

以重庆主城某大学校园为例,对路面、屋面和绿地等3种典型的城市下垫面径流水质进行了监测,指标包括pH、悬浮固体（SS）、化学需氧量（COD）、氨氮（NH3-N）、总磷（TP）等。研究结果表明：除TP外主要污染物质的平均浓度均超过地表水环境Ⅴ类标准,降雨径流SS的平均浓度可高达1.73×103mg/L,COD和NH3-N平均浓度可高达76.25 mg/L和3.67 mg/L;存在显著地初期冲刷效应,混凝土路面的SS、COD、NH3-N的初期径流浓度分别为2.33×103mg/L、106.4 mg/L、5.64 mg/L,初期径流浓度相当于全场降雨径流浓度的2-4倍左右,其最高值出现在产流后10~15 min内。对比3场不同降雨强度下的径流水质,降雨强度越大,径流污染物浓度越高,其中降雨强度对大坡度路面的地表径流污染物浓度影响更大。

Characterization of Stormwater Runoff Pollution in Mountain City

Taking indicators the case of an university campus runoff quality in Main Urban Area of Chongqing,three kinds of stormwater runoff quality were monitored,where indicators included pH,suspended Solids（TSS）,chemical oxygen demand（COD）,ammonia-nitrogen（NH3-N）,total phosphorus（TP）,and so on.The results show that the average concentration of stormwater runoff pollutants exceed the fifth level of the environmental quality standards for China except TP,SS concentration of runoff can reach 1 730 mg/L,COD and NH3-N concentration of runoff can reach 76.25 mg/L and 3.67 mg/L;First flush takes effect evidently,and SS、COD、NH3-N first flush concentrations of concrete road surface were 2330mg/L,106.4mg/L,5.64mg/L.First flush concentrations were equivalent to 2-4 times of Event Mean Concentrations（EMCs）,and the highest concentration value of pollutants appeared when runoff produced 10~15 minutes later.Comparison on runoff quality of three different rainfall intensity,higher intensity was positively correlated with TSS,COD,NH3-N,and TP concentrations,among which rainfall intensity taked greatest effect on runoff pollutants concentration of large slope road.