长期干旱条件下生物滞留系统填料改良研究

Study on operation efficiency of improved biologicalretention facility under long-term drought

生物滞留系统是海绵城市建设的优选设施之一,其填料种类对水质处理效果有非常重要的影响。通过设计生物滞留柱实验,以天然土壤、建筑砂、木屑混合作为基本填料,以绿沸石、粉煤灰作为改良材料,在前期干旱天数(ADD)为2个月的情况下,研究了在填料层中单独及同时添加绿沸石、粉煤灰改良,不同填料层构建下在干旱期后一段时间内的植物生长情况、系统渗透性、水质处理效果。结果表明,在6种填料组合中,在填料中单独添加绿沸石时植物生长状态最好;绿沸石和粉煤灰混合添加时填料的渗透性能最好;在填料中混合添加绿沸石和粉煤灰时对COD、NH3-N的去除效果最好,去除率分别为75%~90%,75%~95%;不添加绿沸石和粉煤灰时对TP的去除效果最好,去除率为85%~90%。采取不同方式改良的填料性质有较大的差异,但相较于传统砂土填料,合理改良后的填料有更好的植物长势、渗透性、污染物综合处理能力。

Bioretention system is one of the preferred facilities for sponge city construction,and its filler type has a very important impact on water quality treatment effect.Through the design of bioretention column test,natural soil,building sand and sawdust were used as the basic fillers,and zeolite and fly ash were used as the improvement materials.Under the condition of the early drought days(ADD)of 2 months,the plant growth,system permeability and water quality treatment effect in a period of time after the drought period were studied when zeolite and fly ash were added separately and simultaneously in the filler layer.The results showed that among the six filler combinations,the plant growth state was the best when the green zeolite was added alone.The permeability of the filler was the best when the green zeolite and fly ash were mixed.For the removal effect of pollutants,the removal effect of COD and NH 3-N was the best when mixed with zeolite and fly ash in the filler,and the removal rates were 75%~90%and 75%~95%,respectively.The removal efficiency of TP was the best without adding green zeolite and fly ash,and the removal rate was 85%~90%.The properties of fillers modified by different methods were quite different,but compared with the traditional sand fillers,the reasonably modified fillers had better plant growth,permeability and comprehensive treatment capacity of pollutants.