Reduction of Arsenic in Groundwater from Hetao Plain with the Involvement of Indigenous Microbes

In order to understand the effect of microbial activities on the occurrence of high arsenic groundwater,microcosm experiments were conducted using the indigenous microbe (YH002) isolated from high arsenic groundwater collected from Hetao Plain. The experiments show that the microcosm supplemented with bacteria and glucose,bacterial metabolism can excrete the organic acid which can cause pH decline. Under anoxic conditions,the maximal OD values reached 0.189 on the 7th day and the pH reduced to 6.22. However,under oxic conditions,the maximum of OD value also occurred on the 7th day with the value of 0.286,while pH values reduced to 6.04 at the end of the experiment. The initial concentration of As (III) was 74 μg/L,accounting for 11.2% of the total arsenic,when at the presence of the microbe and glucose,As (III) concentrations were 278 μg/L and 310 μg/L,accounting for 42% and 47% of the total arsenic,in the N₂ and O₂ atmosphere,respectively. The experimental results show that the indigenous microbe is capable of reducing As (V) to As (III) in groundwater.