辽河保护区七星湿地水质评估及模型模拟

支流已经成为辽河干流的重要污染源,在支流河口建设大型人工湿地可以阻控支流污染物.为揭示辽河保护区七星湿地的净污效果,在对七星湿地水质、水量进行监测的基础上,采用内梅罗污染指数法对其有机物和营养物状况进行评价,并计算污染物在湿地中的去除量,最后利用归趋模型对污染物变化情况进行模拟.结果表明:内梅罗污染指数在支流河入口处较高,万泉河污染最严重;支流水体在经过湿地净化后,水体污染程度有所下降.植物生长期内(5—10月)七星湿地对COD去除总量为26.83 t,削减率为35.3%;对氨氮的去除总量为2.63 t,削减率为37.9%;对总磷的去除总量为0.40 t,削减率为52.9%.衰减方程模型对于COD、TP及不同形态氮拟合效果一般;多元参数回归模型及Monod机制模型较好地模拟了湿地Cout(NH+4-N)和Cout(NO-3-N)的变化.对Monod机制模型参数进行计算可得:kNH+4=24.987 L·m-2·d-1,kmax,NO-2=77.696 mg·m-2·d-1,KS,NO-2=0.114 mg·L-1.相关模型参数可用于湿地氨氮与硝氮浓度的预测.因此,多元参数回归模型及Monod机制模型可应用于类似湿地Cout(NH+4-N)和Cout(NO-3-N)变化的模拟及预测.

Water quality evaluation and modeling of Qixing wetland in Liao River Conservation Area

The tributaries of Liao River are the pollution sources of the mainstream, which may be controlled by large-scale construction of wetland in the tributary estuary. In order to understand the pollutant removal efficiency of constructed wetland, i.e. Qixing wetland, the Nemerow pollution index was used to evaluate the variation of organic matter and nutrient based on the long-term monitoring of water quality in the wetland. The removal of pollutants was calculated, and models were developed to simulate and predict the pollutants reduction. The results showed that the Nemerow Pollution Index of the entrance to the tributaries was high and Wanquan River was the most seriously polluted tributary. The tributary water can be purified when it flowed through the Qixing wetland, and 26.83 t of COD, 2.63 t of ammonia nitrogen (NH₄⁺-N) and 0.40 t of total phosphorus (TP) could be removed with the reduction rates of 35.3%, 37.9% and 52.9%, respectively. The model simulation results showed that Decay equation could reasonably describe the concentration variation in COD, TP, NH₄⁺-N and NO₃^--N. The multi-Parameter regression model and Monod equation could well simulate the C_out(NH₄⁺-N) and C_out(NO₃^--N) concentrations in wetland. The parameters of Monod equation were obtained: k_NH4⁺ = 24.987 L · m^-2 · d^-1, k_max,NO^-2 = 77.696 mg · m^-2 · d^-1, K_S,NO^-2=0.114 mg · L^-1, which could be used in the prediction of C_out(NH₄⁺-N) and C_out(NO₃^--N). Therefore, both of the multi-Parameter regression model and Monod equation can be applied to simulate and predict the variations of ammonium and nitrate nitrogen in similar wetlands.