天然有机碳源强化硫酸盐还原菌修复酸性矿山废水效能OA

With the continuous expansion of mineral resource exploitation,the environmental pollution caused by acid mine drainage(AMD)is becoming increasingly severe.Sulfate-reducing bacteria(SRB)technology has garnered widespread attention due to its advantages such as low cost and environmental friendliness,but its practical application is still limited by high carbon source costs and insufficient efficiency of single carbon source.In this study,five natural organic carbon sources—cassava peel,maize straw,bagasse,buckwheat husk,and pine wood shavings—were selected to establish both single leachate and solid carbon source-leachate combined remediation systems.The effects of different carbon sources on the remediation efficiency of SRB in treating simulated AMD were systematically evaluated.Quantitative fluorescence polymerase chain reaction(qPCR)was used to determine the abundance of dsrB,and three-dimensional excitation-emission matrix fluorescence spectroscopy(3D-EEM)was used to analyze the composition of dissolved organic matter in carbon source leachate,and intrinsic mechanism of carbon source affecting the repair efficiency was revealed from the aspects of microbial activity,organic composition and material structure by scanning electron microscopy(SEM).The results indicated that cassava peel exhibited the best remediation performance in both systems.In the combined remediation system,the pH increased to a maximum of 9.06,and the SO42-removal rate reached 96.4%.qPCR analysis revealed that the abundance of the SRB functional gene dsrB in the cassava peel system was significantly higher than in other carbon source systems((2.85±0.67)×105 copies·mL-1),and extracellular polymeric substance(EPS)secretion was also the most active(181.30±11.27)mg·L-1.3D-EEM analysis showed that the leachate of cassava peel was rich in easily degradable protein-like components,whereas pine wood shavings and buckwheat husk were dominated by recalcitrant humic-like substances,leading to restricted SRB metabolism.SEM observations further confirmed that cassava peel exhibited a porous network structure conducive to SRB attachment and mass transfer,while pine wood shavings had a dense surface with few pores,severely limiting carbon release and microbial growth.This study provided a theoretical support for the development of low-cost,high-efficiency microbial remediation of AMD,which was of great scientific significance to promote ecological restoration in mining areas.