水力负荷对生物滞留系统渗流性能及孔隙率的影响

Effect of hydraulic loading on percolation performance and porosity of bio-retention cell system

生物滞留池是处理初期雨水径流的主要手段,不仅能够滞水蓄水、对初期径流污染的削减也有着一定的效果,且其在水处理领域的应用范围正在不断扩大.本项试验研究4种不同进水负荷下生物滞留池系统的渗透系数、平均孔隙率的变化,结果表明:渗透系数随运行时间逐渐降低,平均孔隙率也随运行时间逐渐变小,并最终趋于稳定,当进水负荷小于2.0 m^3/(m^2·d)时渗透系数与平均孔隙率具有一定的相关性.生物滞留池在运行25 d左右时结构达到稳定.进水负荷大于等于4 m^3/(m^2·d)时,水力冲刷作用对生物滞留池内部结构影响较大,渗透系数与平均孔隙率的变化规律不明显.

Bio-retention cell system is the main way to treat rain water runoff in the initial stage.It can not only retain water and save it,but also has a certain effect in reducing pollutants.Therefore,its applications in the field of water treatment are gradually expanding.The variation of permeability coefficient and average porosity of the bio-retention cell were investigated experimentally under four different influent loads.Results coming out from the investigation indicate that both the permeability coefficient and the average porosity decrease gradually with running time,and tend to be stable finally.When the influent load is less than 2.0 m^3/(m^2·d),there is a certain correlation between the permeability coefficient and the average porosity.The biological structure appearing in the bio-retention cell system reaches stable when it runs for about 25 days.When the influent load is greater than or equal to 4 m^3/(m^2·d),the hydraulic scouring effect has a great influence on the internal biological structure of the bio-retention cell system.Variations of the permeability coefficient and the average porosity are not distinct in this case as a result.