基于HYDRUS-1D模型的不同生物滞留池中水分及溶质运移特征模拟

Simulation of water and solute transport characteristics in different bioretention tanks using HYDRUS-1D model

通过生物滞留池中试和HYDRUS-1D软件,构建了水分和溶质在不同填料生物滞留池中的运移模型,研究了不同情景下生物滞留池对水量和水质的调控效果.同时,利用Morris筛选法对模型参数的不确定性进行分析.结果表明,V、h、θs、n、Ks等参数对水分运移的影响较大,V、c、h、Kd等参数对溶质运移的影响较大.选取试验1~4的数据对模型进行率定,试验5~9的数据对模型进行验证,水量及溶质的Nash-suttcliffe模拟效率系数(Ens)均在0.85以上.采用率定后的模型对预设情景进行模拟,结果表明,人工填料层为粉煤灰+沙的生物滞留池对水量综合削减率为70.54%,对污染物负荷综合削减率为83.88%,效果最佳;增加填料层的厚度可以提高水量削减效果和污染物去除效果,在30、40、50 cm 3种厚度下,填料厚度为50 cm时,水量综合削减率为64.00%,污染物负荷综合削减率为77.71%,效果最佳.进水水量的增大会降低水量削减效果和污染物去除效果,1年重现期下比10年重现期下水量综合削减率大35.97%,污染物负荷综合削减率大20.19%.污染物的去除效果随进水浓度的增大而降低,高、低浓度进水下污染物负荷综合削减率相差7.49%.

Through the pilot experiment of bioretention tanks and using the HYDRUS-1 D software,the migration models of water and solutes in different bioretention tanks are established. The models are used to study the regulation of bioretention tanks on water and solutes under different scenarios. The uncertainty of model parameters is analyzed through the Morris method. The results show that： the parameters V,h,θs,N,and Kshave a great influence on water transport,while the parameters V,C,h,and Kdhave a great influence on solute transport. The data from test 1 to test 4 are used to calibrate the model,and the data from test 5 to test 9 are used to validate the model. The Nash-Sutcliffe efficiency coefficients of water and solutes simulation are all above 0.85. The calibrated models are used to simulate the hypothetical situations. The results show that： The bioretention tank equipped with an artificial filler layer of fly ash mixed with sand works best,and the 70.54% of volume reduction rate of water and 83.88% of pollutants removal rate are respectively obtained. The increase of media thickness can enhance the reduction of water volume and removal of pollutants. Among three thicknesses of 30,40 and 50 cm,the media with 50 cm thickness is the most efficient,the comprehensive reduction rates of water volume and pollutants load are respectively 64.00%and 77.71%. With the increase of influent volume,reduced the water reduction and pollutants removal. The comprehensive water volume and pollutants reduction rates under 1-year recurrence period are respectively 35.97% and 20.19%,greater than those under 10-year recurrence period. With the increase of influent concentration,the removal rates of pollutants are reduced. The pollutant removal rate under high influent concentration is 7.49% less than that under low influent concentration.