基于 MIKE11 的合流制截流倍数优化

文章以安徽阜阳地区界首市界临河为例，以化学需氧量（chemical oxygen demand，COD）和氨氮为指标，按照排放的污水水质、污染物质量浓度差异，将研究区域划分为工业区、居民区、城中村3个区域，采用取最值法，将区域内溢流口概化为连续恒定的污染源，并设计分质截流倍数，建立MIKE11水动力水质模型；从降低河流中污染物质量浓度、提升动态水环境容量2个方面，对比分质截流与传统截流的截流效果。结果表明：采用传统截流倍数时，界临河中河长制断面处， $ \rho_{COD} $、 $ \rho(NH_{3}-N) $分别降低28%、25%；采用分质截流倍数时， $ \rho_{COD} $、 $ \rho(NH_{3}-N) $分别降低39%、32%；在COD和氨氮的动态水环境容量方面，分质截流比传统截流分别提升30%、16%，可见分质截流对河流水质改善效果优于传统截流。研究结果可为老城区截流式合流制排水系统改造提供参考。

Taking the Jielin River in Jieshou City, Fuyang area as an example, this paper uses chemical oxygen demand (COD) and ammonia nitrogen as indicators, and divides the study area into industrial area, residential area and urban village according to the sewage water quality and pollutant concentration. A single rainfall event with a rainfall intensity greater than 1 is studied, the maximum value method is used to generalize the overflow in the area as a continuous and constant pollution source, the quality-based interception ratios are designed, and the MIKE11 hydrodynamic water quality model is established. From the two aspects of reducing pollutants in the river and increasing the dynamic water environmental capacity, the interception effects of quality-based interception and traditional interception are compared. The results show that when the traditional interception ratios are used, $ \rho_{COD} $ and $ \rho(NH_{3}-N) $ at the river chief system section of Jielin River are reduced by 28% and 25%, respectively; when the quality-based interception ratios are used, $ \rho_{COD} $ and $ \rho(NH_{3}-N) $ decrease by 39% and 32%, respectively. In terms of the dynamic water environmental capacity of COD and ammonia nitrogen, the quality-based interception increases by 30% and 16%, respectively, compared with the traditional interception. It can be concluded that the effect of the quality-based interception on river water quality improvement is better than that of the traditional interception. The study can provide reference for the selection of the interception ratio of confluent drainage system in old urban areas.