山地城市生物滞留带改良填料除氮效果研究

Study on Nitrogen Removal Efficiencyt of Improved Filler in Bioretention Zone in Mountainous Cities

选取3种除氮性能好的填料与典型山地城市生物滞留带常用土壤按照不同体积配比混合,作为生物滞留系统的填料层进行氮污染物去除试验研究。结果表明:35%蛭石组对氨氮的去除效果最好,去除率稳定在95%左右,其次为火山岩,最差为沸石;与其它2种填料比较,35%沸石组对TN的去除效果最好,但稳定性不如蛭石组合填料。相同填料层对氨氮的去除效果优于TN,当填料配比为50%时,除氮率均低且不稳定。综合考虑填料对氨氮和TN的去除效果时,蛭石、沸石、火山岩是生物滞留带填料较好的选择。另外,它们与土壤的最优配比分别为蛭石35%、沸石35%和火山岩20%。

Three kinds of fillers with good nitrogen removal performance were mixed with common soils in typical mountainous urban bioretention zones according to different volume ratios,and it was used as filler layers of bioretention system to remove nitrogen pollutants in the experimental study.The results showed that the removal of NH3-N was the best in the 35% vermiculite group,the removal rate was stable at about 95%,followed by volcanic rocks,and the worst was zeolite.Compared with the other two fillers,the 35% zeolite group has the best removal efficiencyt on TN,but the stability is not as good as the vermiculite composite filler.The removal efficiency of NH3-N is better than TN in same filler layer.When the filler ratio is 50%,the nitrogen removal rate is low and unstable.When considering the removal efficiencyt of fillers on the TN and NH3-N,vermiculite,zeolite and volcanic rock are better choices for bioretention zone packing.In addition,their optimal ratio to soil is 35% for vermiculite,35% for zeolite and 20% for volcanic rock.