基于环境自净能力的龙凤湿地水质改善优化调控模型

为解决城市湿地生态系统存在的严重污染问题,找到合理的排污削减方案,选择大庆市龙凤湿地作为研究对象,以主要的污染物NH_3-N、TP、COD_(Cr)和石油类污染物为指标,应用MIKE21建立试验湿地二维水动力和水质耦合模型,采用数值模拟的方法,研究提出湿地水质改善的优化调控模型.进而,采用模拟试验研究了清淤、曝气、补水及上述措施两两组合下的调控方案对改善龙凤湿地水质效果的影响.结果表明:单一工程措施下无法使染物削减到控制目标浓度,各类措施的削减效果为补水清淤曝气;在各组合情况下,补水+清淤方案的削减作用更佳;在工程措施相同情况下,提高排污标准也能起到削减作用.最后,在考虑不同排污方式下既能使污染物排放达标、又能充分利用湿地纳污能力的前提下,优选出了最佳方案.

Optimization of water quality improvement program for Longfeng wetland considering the purification of aquatic plants

In order to solve the serious pollution of urban wetland ecosystem, Longfeng wetland in Daqing City was taken as the research object to find a reasonable sewage reduction scheme. First of all, main pollutants including NH₃-N, TP, COD_Cr and petroleum pollutants were selected as indicators. And the two-dimensional hydrodynamic and water quality coupling model was established by application of MIKE 21. Then the optimal regulation method aiming at improving water quality of wetland was proposed by the method of numerical simulation method. In addition, the dredging, aeration, water replenishment were researched by simulation experiment and the effects on the water quality improvement of Longfeng wetland under different combination of the measures mentioned above were analyzed. The simulation results show that the pollutants could not be reduced to the target concentration under single engineering measure, and the reduction effect of water replenishment is the best, dredging the second best, aeration the last. In the case of different engineering measures, the reducing effect of the replenishment and dredging combination is better. Improving the sewage standards can also play a role in reducing pollutants. Finally, the best solution which can not only guarantee the discharge of pollutants reaching the standard, but also make full use of wetland pollutant carrying capacity was selected.