改良生物滞留系统强化对雨水径流中氮磷的去除

Enhanced Bioretention Systems for Nutrients Removal from Rain-runoff

传统生物滞留池对N、P去除效果较差且不稳定,甚至会出现N、P的负去除现象。文章采用改良复合填料,结合双层填料和滤池饱和区组合设置,构建了4组模拟生物滞留实验柱,分别加入传统填料(C1)和改良复合填料(C2、C3、C4),并设置滤池饱和区的组合式排水系统以强化脱氮除磷效果。利用半合成模拟雨水作为实验进水对出水中氮磷的去除效率进行了评价和比较。此外,还评价了介质深度、干旱期对生物滞留柱中磷的截留和反硝化酶活性的影响。填充C2的实验柱对总磷的去除效果最佳(93.70%);填充C1的实验柱对总磷的去除效果较差(57.36%);填充C3的实验柱去除硝酸盐和总氮的性能最佳(分别为83.54%和92.15%)。结果表明,通过改良填料羟基铝蛭石污泥、双层填料和滤池饱和区组合设置,可以有效地改善径流水质,并可为高效雨水处理提供新的生物滞留池配置方法。

The traditional bioretention system has poor and unstable removal of nitrogen and phosphorus,even the negative removal of nitrogen and phosphorus could occur.Using modified composite filler,bi-layer media and filter tank saturation area combination setting,4 simulated bioretention experimental columns were constructed,including traditional filler(C1)and modified composite filler(C2,C3,C4),and a combined drainage system of the filter tank saturation area to strengthen the nitrogen and phosphorus removal effect.The removal efficiency of nitrogen and phosphorus in outgoing water was evaluated and compared by using semi-synthetic simulated rain water as experimental inlet.In addition,the effects of medium depth and drought on phosphorus retention and denitrifying enzyme activity(DEA)in bioretention columns were evaluated.The experi⁃mental columns filled with C2 had the best removal effect on total phosphorus(93.70%),however,the removal effect of total phosphorus by filling C1 experimental columns was poor(57.36%).Used to remove nitrate(NO3--N)and total nitrogen(TN),the experimental columns filled C3 showed the best performance(83.54%and 92.15%,respectively).The results show that the combination of hydroxy-aluminum vermiculite sludge,bi-layer media and filter saturation area can effectively improve the runoff water quality and provide new biodetention system for efficient rainwater treatment.