弱透水性下垫面降雨径流污染物输移特性

为了研究弱透水性下垫面降雨径流污染物的输移特性,选择兰州市作为典型城市,基于其降雨分布特点和面源污染特点提出了弱透水性下垫面径流污染物输移模型。通过对大学校园内屋面、路面及其他弱透水性下垫面组合形式下的天然降雨径流取样检测,分析了浊度,COD_cr,TN和TP等主要污染物浓度随时间的变化规律及污染物相关性研究,同时运用模型计算径流污染物初期负荷率。结果表明:校园弱透水性下垫面,降雨径流历时10～20 min各污染物浓度达到峰值。径流历时30 min内,降雨径流浊度,COD_cr,TN和TP的污染物负荷率可达到65%～85%。在中小降雨条件下,降雨径流过程中各污染物显著相关,径流污染物输移模型的适用性较好。

Research on the Transport Characteristics of Pollutants in Rainfall Runoff on the Underlying Surface with Weak Water Permeability

In order to study the transport characteristics of pollutants in rain-runoff on the impermeable underlying surface,Lanzhou was selected as a typical city,and based on its rainfall distribution characteristics and non-point source pollution characteristics,a model for the transport of pollutants from the impermeable underlying surface was proposed.Through sampling and testing of natural rainfall runoff under the combination of roof,road surface and other weakly permeable underlying surfaces on the university campus,turbidity,COD_cr,TN and TP and other major pollutants concentration changes over time were analyzed,the pollutant correlation was examined,and the model was used to calculate the initial load rate of runoff pollutants.The results show that the concentration of pollutants in the runoff reached the peak while the rainfall runoff on weak permeable surface on campus lasted for 10~20 minutes;while the runoff lasted within 30 minutes,the pollutant load rate of rain runoff turbidity,COD_cr,TN and TP could reach 65%~85%.The applicability of runoff pollutant transport model was better,and the pollutants were significantly correlated in the process of rainfall and runoff under the condition of small and medium rainfall.