生物墙对地下水中六价铬的去除效果模拟研究

Simulated laboratory study on effect of removing chromium(Ⅵ) from groundwater using permeable biowall

通过土柱实验模拟地下水环境,研究以发酵树皮为主要反应介质的渗透性生物墙对地下水中六价铬的去除效果,为六价铬污染地下水的修复提供方法和依据。结果表明,模拟生物墙运行数天后,墙内形成弱碱性(pH 7~8)、强还原(Eh<-100 mV)环境,有利于六价铬转化为三价铬并生成沉淀。在进水六价铬浓度为20 mg/L、水流速度为3.7 cm/d的运行条件下,3周期间生物墙对六价铬的去除率稳定在98%左右,生物墙内沿水流方向三价铬的浓度先上升后下降(最高达6.6 mg/L),出水三价铬约为1.0 mg/L。吸附和微生物转化是生物墙对水中六价铬去除的主要反应。

To provide a method and basis for remediating chromium( Ⅵ) polluted groundwater,column experiments were performed in the laboratory to study the removal of chromium(Ⅵ) by permeable biowall filled with fermented mulch as the reactive material. The experimental results showed that the environmental condition in the simulated biowall became alkalescent( pH 7 ~ 8) and highly reduced( Eh <- 100 mV) after several days' of operation,which was favorable for the reduction of chromium(Ⅵ) to chromium(Ⅲ) and forming precipitation. Under the chromium(Ⅵ) concentration of 20 mg /L and water flow velocity of 3. 7 cm /d,the removal rate for chromium(Ⅵ) was stable at about 98% during the study period of three weeks,and the chromium(Ⅲ) concentration along the flow path in the biowall first increased and then decreased,with the chromium(Ⅲ) concentration in the outlet water being about 1.0 mg/L. Adsorption and microbial transformation were major reactions involved in the removal of chromium(Ⅵ) from water by the permeable biowall.