某大学校园及周边不同下垫面降雨径流污染过程研究

以大学校园及其周边区域降雨、径流和径流水质3年观测试验数据为依据,分析不同下垫面降雨过程、径流过程及污染物运移过程的规律及特征,计算出不同下垫面污染物输出系数。结果表明,雨水中氨氮浓度高于Ⅳ类水质标准,悬浮物、硝酸盐氮和COD浓度均低于最高水质标准;产流时间与产流前平均降雨强度呈幂函数关系,不同下垫面径流过程与降雨过程呈正相关关系;径流强度是径流携带污染物运移的重要影响因素,径流强度增加,径流携带污染物质量随之上升。污染物输出系数计算结果表明,屋面主要污染物为含氮污染物,餐饮街道主要为有机污染,不同下垫面悬浮物、硝酸盐氮、氨氮和COD输出系数均值分别为2 294.91、7.21、14.86、430.34kg/hm2/a。

Study on Rainfall-Runoff Pollution Process of Different Underlying Surfaces in University Campuses and Their Periphery

Based on three years of observational experimental data of rainfall,runoff and water quality in university campuses and their periphery,the laws and characteristics of rainfall process,runoff process and pollutant transport process under different underlying surfaces are analyzed,and the pollutant export coefficients are calculated.The results show that the concentration of ammonia nitrogen in rainwater is higher than theⅣ water quality standard.Concentrations of suspended solids,nitrate nitrogen and COD are lower than the highest water quality standards.There is a power function relationship between the onset time of runoff and the average rainfall intensity before runoff generation.There is a positive correlation between runoff process and rainfall process on different underlying surfaces.Runoff intensity is an important factor affecting the transport of pollutants in runoff.With the increase of runoff intensity,the quality of pollutants carried by runoff increases.The calculation results of pollutant export coefficients show that the main pollutants in roofs are nitrogen-containing pollutants,while the main pollutants in catering streets are organic pollutants.The average export coefficients of suspended solids,nitrate nitrogen,ammonia nitrogen and COD on different underlying surfaces are2 294.91,7.21,14.86,and 430.34 kg/hm2/a,respectively.