城市排水系统的集成化模拟研究

Study on Integrated Simulation of Urban Drainage System

城市排水系统的集成化模拟是国际上推行的一种研究方法,但在我国尚没有相关的实例报道。将美国环保局提供的城市暴雨径流管理模型(SWMM)与清华大学环境系自行研制开发的河流水质模型相结合,构成城市排水系统集成化模拟工具,它可以动态模拟暴雨径流(生活污水)→排水管网→污水处理厂→受纳水体的全过程。以深圳河湾地区为例,针对深圳市提出的排水系统规划布局方案运用该模拟工具进行模拟计算,评估该方案对深圳河湾地区水环境的影响。模拟结果表明,规划方案实施后对深圳河干流水质的改善效果突出,对支流水体水质的改善效果略差,需要进一步优化雨水管网布置和污水厂选址;规划方案可大大提高河水的COD达标率,但TN和TP的达标率仍相对较低,需要加强源头控制并提高污水处理厂的脱氮除磷效果。

The integrated simulation of urban drainage system is a prevailing method to estimate its water environmental impact, however, there have not been any related studies in China. Therefore, integrating Storm Water Management Model （SWMM） from USEPA and a river water quality model from Tsinghua University, an integrated simulation tool was developed. The tool can simulate the municipal wastewater and pollution load transfer procedure including the storm runoff process, sewer system eonveying process, wastewater treatment process and the degradation process in receiving water body. The simulation tool was applied in Shenzhen City to assess the water environmental impact of the sewer system planning scenario. The calculation results show that the planning scenario can enormously improve the water quality of the mainstream of Shenzhen River System, while the improvement of the branches is not enough. The resuhs also show that the scenario has different effects on different water quality indexes, which means that the COD rate satisfies the quality standard while the up-to-standard rate of TN and TP is still very low. Based on the results, some suggestions were given to improve the planning scenario.