北京市水环境非点源污染监测与负荷估算研究

文章对北京全市域范围开展水环境非点源污染监测以及污染负荷估算研究。监测结果表明,天然降雨氨氮、总氮污染程度高;城区典型下垫面降雨径流的有机污染十分严重,其中屋面降雨径流总氮和氨氮污染最严重,路面降雨径流COD和总磷污染最严重;下垫面降雨径流汇入城市排水管网后,由于冲洗下水道中的沉积物,使得水质污染进一步恶化。农业典型小流域面源污染对水质影响也很明显。城市非点源污染负荷估算选用SWMM暴雨径流模型,农业非点源污染负荷模型选用改进的输出系数模型,估算结果表明:城市非点源污染主要来自大气湿沉降、综合用地、路面和屋面等,农业非点源污染主要来自耕地和林地;全市污染物排放总量中,点源排放总量与非点源排放总量基本各占50％左右。为进一步挖掘污染减排空间,完善总量减排体系提供了依据。

Non-Point Source Pollution Monitoring and its Loads Estimation Study on Surface Water Environment in Beijing

Non-point source pollution of surface water environment in Beijing was monitored and its loads estimation was studied. Monitoring results: natural rainfall was polluted on NH₃-N and TN; organic pollution of storm runoff was very serious in urban typical underlying surface: TN and NH₃-N was most serious in roof runoff; COD and TP were most serious in road runoff. Runoff of underlying surface cause sharper flush on deposit so that its water quality was more polluted when it enter sewer pipe system. Non-point source pollution was also serious in agricultural typical river basin. For pollution loads estimation, SWMM storm runoff model was used for urban non-point source; improved export coefficient model was used for agriculture non-point source. Estimate results: urban runoff mainly comes from wet deposition, runoff of roof and road; agricultural runoff mainly comes from farming land and forest land. The discharge amount in Beijing, either point source or non-point source is almost 50%. It provided scientific basis for reduction of discharge amount.