基于MIKE21的三峡库区涪陵段排污口COD扩散特征模拟及对下游水质的影响

COD Diffusion Simulation Based on MIKE21 in Sewage Outfall of Peiling Section of the Three Gorges Reservoir Area and Its Impact on Downstream Water Quality

采用MIKE21建立蓄水后涪陵长江水动力模型平台,通过耦合污染物传输模型(TD)来研究上游COD排放对城市取水口附近水质的影响时间及程度,并提出应对措施.结果显示,研究区距上游边界2km处的排污口所排COD在5～10min内就能扩散到取水口,使周围COD浓度较背景浓度值加倍,44号排污口对取水口水质下降影响最为严重.稳定后,日排污1000t以上的排污口使取水口附近COD浓度升为背景值的5.24倍,严重影响了下游城市的取水安全.

Using MIKE21, a dynamic water model of Yangtze River after water storage in Peiling is established. Through coupling pollutants transport model, the model is applied to simulate the effect time and level of upstream COD emission on water quality near the city water intakes, and some countermeasures are proposed. The results show that, COD of steak outlet 2kin upstream can spread to city water intakes in 5 to 10 minutes, and lead to a double concentration of the background, and 44th water intake is the most serious of all intakes. The sewage outfalls above 1000t daily make the COD concentration around the city intakes rise to 5.24 times than the background value. This will seriously affect water security of the downstream city.