Isolation And Characterization Of A Strain Of Sulfate Reducing Bacteria And Effect In Treatment Of Underground Wastewater From Decommissioned Acid In-situ Leaching

acid in-situ leaching cause potential groundwater contamination in the ground leach mining area and surrounding ore-bearing aquifers and requires treatment of this type of wastewater.In this paper,a strain of sulphate-reducing bacteria was isolated and purified from the tailings of an acid heap leach uranium mine,and the growth characteristics of the strain and the effect of carbon sources such as pericarp fermentation solution on the desulphurisation of the strain were investigated.The main research results are as follows:（1）A strain of sulfate-reducing bacteria A3-21ZLL was isolated from a uranium mine tailings slag and identified as a genus of desulfurizing vibrio.The optimum growth carbon source of the strain is sodium lactate,the optimum p H is 6.66,the optimum temperature is 35℃;under the acidic and lower temperature conditions has a certain desulfurization effect,the desulfurization rate at p H 4.38 is 38.9%,the desulfurization rate at 17℃is 50.8%;under the best culture conditions,the strain A3-21ZLL culture time of about 12h into the logarithmic growth period,stable period can maintain nearly 16 hours.（2）peel fermentation broth and orange peel fermentation broth;the optimum m（COD）/m(SO₄^2-)for culturing A3-21ZLL with apple peel fermentation broth as the carbon source was 7,and The desulphurisation rate was 94.51%and the optimum inoculum was 10%,with 73.7%desulphurisation（3）A3-21ZLL uses apple peel fermentation broth as a carbon source to treat groundwater from decommissioned acid in-situ leaching.The results show that the p H of the groundwater-fermentation broth mixture rose from 3.98 to 4.55 after 12 days of treatment under static conditions,and the removal rates of SO₄^2-,U⁶⁺and Fe²⁺were38.1%,41.7%and 53.3%respectively;the p H of the ascending flow anaerobic bioreactor rose from 3.98 to 5.78 after 10 days of treatment,and the removal rates of SO₄^2-,U⁶⁺and Fe²⁺reached 91.79%,88.57%and 97.2%respectively.After 10 days of treatment in the ascending flow anaerobic bioreactor,the p H increased from 3.98 to5.78,and the removal rates of SO₄^2-,U⁶⁺and Fe²⁺reached 91.79%,88.57%and 97.2%,respectively.The SO₄^2-,Fe²⁺concentration and p H of the groundwater and fermentation liquid mixture after treatment by the reactor were all in compliance with the Class IV water standard in the Groundwater Quality Standard GB/T 14848-2017,with good results.This strain of the genus Desulfovibrio,which has strong acid and low tem perature tolerance,is expected to be used in the bioremediation of groundwater in decommissioned acid in-situ leaching.