不同入河排水口降雨径流污染特征识别

Recognition of rainfall runoff pollution characteristics of different river drainage outlets

为明确降雨径流对受纳水体的影响,本文以萧太后河径流入河排水口为研究对象,通过原位监测降雨量、径流量和径流水质的方式,初步揭示不同入河排水口降雨径流污染特征.研究结果表明,首闸合流制溢流口、台湖路边沟和前营村分别在累计降雨12、5.0和3.2 mm及分别晚于降雨2.0、1.5和1.3 h时开始产流,TP、NH3⁃N、COD和TN均在初期降雨过程中浓度较大,台湖路边沟多场次降雨的场次降雨径流平均浓度(EMC)的均值及波动范围均高于其他两类入河排水口(不包括SS指标).雨强、降雨量和雨前干期长度等与排水口中的污染负荷指标具有一定的相关性,其中,雨强分别与首闸和台湖路边沟的TN呈正相关,与前营村的TP呈负相关.3类入河排水口径流污染指标中,NH3⁃N与不同的指标存在一定的相关性,且回归分析的R2均大于0.9.萧太后河流域场次降雨入河污染负荷TP、NH3⁃N、COD和TN分别为0.27、2.82、43.77和4.98 t.建议从总污染负荷控制的角度确定末端调蓄容积,截留初期约16 mm降雨.

In order to clarify the impact of rainfall runoff in the receiving water body,this study takes the runoff into the river drain as the research object,preliminary reveals the characteristics of rainfall runoff pollution in different river drainage outlets by the on⁃site monitoring of rainfall,runoff and runoff water quality.The results show that the Shouzha,Taihu roadside gully and Qianying village started produce runoff after 2,1.5 and 1.3 h of rainfall,and the accumulated rainfall of 12,5 and 3.2 mm respectively.The concentration of TP,NH3⁃N,COD and TN is high during the initial rainfall.The average value and fluctuation rang of the event mean concentration(EMC)in Taihu roadside gully are significantly higher than others(but SS).Rain intensity,rainfall and the length of the dry period before rain have a certain correlation with the pollution load index in the drainage outlet.Among them,the rain intensity is positively correlated with the TN of the Shouzha and Taihu roadside gully,respectively,and negative correlation with the TP of Qianying Village.There are certain correlations between NH3⁃N and different indicators in the three river drainage outlets,and the R2 of the regression analysis is greater than 0.9.The pollutant loads,TP、NH3⁃N、COD and TN,of the Xiaotaihou from rainfall were 0.27,2.82,43.77 and 4.98 t,respectively.It is recommended to determine the terminal storage volume from the perspective of total pollution load control and intercept the initial 16 mm rainfall.