Study On Treatment Of Acid Mine Drainage By Sulfate Reducing Bacteria Strengthened By Microelectrolysis

To solve the problems such as low sulfate reduction rate,severe inhibition by heavy metal ions and low p H in biological treatment of acid mine wastewater,this paper proposes the idea of iron carbon micro-electrolysis to strengthen SRB to repair AMD.Through the method of filling the reactor with iron-carbon micro-electrolysis filler and inoculating SRB,the feasibility and effectiveness of strengthening SRB by iron-carbon micro-electrolysis for reducing sulfate by alienation were analyzed.The optimal packing ratio of SRB dissimilation reduction sulfate was determined.Combined with the analysis of the change of ion concentration along the reactor and the characterization of the packing,the synergistic mechanism of SRB in AMD repair was revealed.The main research contents and results are as follows:?1?An iron-carbon hybrid micro-electrolytic bioreactor,an iron-carbon layered bioreactor,an activated carbon bioreactor and an iron-chip bioreactor were constructed by using a rising-column experimental device.The sulphate concentration of inlet water was gradually increased under the condition of low hydraulic load and sufficient nutrition,the feasibility of SRB reduction of sulfate by iron-carbon microelectrolysis was discussed with the analysis of biological diversity.The results show that when the HRT was 24h,COD/SO₄^2-was 2,and the SO₄^2-concentration in the inlet water was 2500mg/L,the SO₄^2-removal rate in the outlet water could reach 98.5%,which was 3.6%,8.4%and 14.9%higher than that in the control group,respectively.It was verified that the galvanic cell reaction produced by iron carbon could improve SRB activity and sulfate dissimilation reduction ability.The results of high-throughput sequencing showed that the SRB in the micro-electrolytic bioreactor was not a single bacterium,and its relative abundance and diversity were better than those in the control group,and it had higher system stability.?2?The constructed reaction system was used to carry out an experiment on the effectiveness of remediation of sulphate-containing acid wastewater under high hydraulic load and low nutritional conditions to investigate its sulfate dissimilar reduction rate and substrate utilization capacity.The results showed that when the HRT was shortened to 12h,the COD/SO₄^2-decreased to 1.4,the removal rate of SO₄^2-in the micro-electrolytic bioreactor was 96.7%,5.6%,15.7%and21.8%higher than the control group,respectively.Microelectrolytic bioreactor has higher substrate utilization and sulfate removal capacity.?3?Seven groups of iron-carbon mixed microelectrolytic bioreactors with different mass ratios were constructed to carry out the experiment of repairing AMD,and the effect of strengthening SRB in repairing AMD by microelectrolysis was discussed and the packing ratio was optimized.The results showed that SRB in micro electrolysis bioreactor maintained good biological activity and had stable ability to remove sulfate when repairing AMD.When the iron-rates were above 99%.The effluent was clarified and the substrate was less used,which was better than other iron-carbon ratio reactors.?4?The characterization of the filler before and after the treatment of AMD in micro-electrolytic bioreactor was analyzed,and the regeneration experiment of the filler was carried out.In combination with the change rule of ion concentration along the process of micro-electrolysis bioreactor,the removal method of each ion in wastewater by micro-electrolysis bioreactor was discussed:SO₄^2-was reduced to S^2-by SRB and formed precipitation removal with metal ions.Cu²⁺was removed from the surface of iron mainly by deposition of replaced copper.Zn²⁺was removed mainly in the form of sulfide and hydroxide precipitation.Mn²⁺was removed mainly in the form of hydroxide precipitation and co-precipitation of iron ions.TFe is removed by sulfide,hydroxide and flocculation.There are 46 pictures,13 tables and 106 references in this paper.