北运河(北京段)水污染特征时空变化模拟

Simulation of temporal and spatial variation of water pollution characteristics of North Grand Canal (Beijing-Section)

基于不规则网格的MIKE21软件包搭建了北运河水系数值模型，通过逐月参数率定及模拟过程校验，实现了对北运河流场和污染浓度场的二维数值模拟。主要结论为：2015年北运河流域COD、NH3-N、TP和TN四项污染物负荷削减率在16．5％～43．5％之间，其中氮、磷去除效果最为显著。2015年北关拦河闸四项水质指标年均浓度较2013年有所下降，但COD、NH3-N、TP浓度仍超出城镇污水处理厂出水一级B标准的1．3、2．3和2．7倍，仅TN浓度达标。因此，建议北运河流域在控制点源污染的同时，应加大雨污合流管道汛期溢流污水及雨水管道初期雨水的收集和处理，有效控制面源污染入河。

The numerical model for the water system of the North Grand Canal is established with the software package of the ir- regular grid-based MIKE 21 FM, and then the 2 - D numerical simulation on both the flow field and pollution concentration field of the North Grand Canal is realized through the verification made on the processes of the calibration and simulation of the monthly parameters. The main conclusion is that the cut-rates of the four pollutant loads, i.e. COD, NH3 -N, TP and TN, are between 16% ~43.5% , in which the effects of the removals of nitrogen and phosphorus are most significant. In 2005, the annual mean concentrations of the four water quality indexes at Beiguan Sluice are lowered with a certain scale than those in 2013, but the con- centrations of COD, NH3 - N and TP exceed the standard B for the primary municipal effluent from municipal wastewater treat- ment plant by 1.3, 2. 3 and 2. 7 times, and only the concentration of TN meets the standard. Therefore, it is suggested that while controlling the point-source pollution within the basin of the North Grand Canal, the collection and treatment of the sewer overflow from the rainwater-sewer combined drainage conduit during flood season and the initial rainwater from the storm sewer conduit must be enlarged and the non-point source pollution must be effectively controlled as well.