POTENTIAL OF AUTOCHTHONOUS SULFATE-REDUCING MICROBIAL COMMUNITIES FOR TREATING ACID MINE DRAINAGE IN A BENCH-SCALE SULFIDOGENIC REACTOR

Abstract Biological acid mine drainage treatment depends significantly on inoculum origin, pH, COD/sulfate ratio, and carbon source. In this study, the performance and microbial diversity of anaerobic batch reactors used for sulfate reduction was evaluated. A medium COD/sulfate ratio of 1.14 ± 0.10 was used, and the evaluation was performed in two steps: Phase 1, based on the inoculum source (autochthonous, AUT, and non-autochthonous, N-AUT); and Phase 2, based on the carbon source (lactate, ethanol, and formate) and low pH. In Phase 1, the sulfate removal using both AUT and N-AUT biomasses were similar, 53% and 59%, respectively. In Phase 2, ethanol and lactate as electron donors yielded similar sulfate removal efficiencies of 42% and 44%, respectively, at neutral pH. When the initial pH was reduced from 4 to 3, sulfate removal using formate remained nearly constant at 34%, whereas it reduced from 43% to 30% with lactate, and dropped significantly from 18% to 7% with ethanol. Denaturing gradient gel electrophoresis analyses for sulfate-reducing bacteria revealed their presence in all samples. Microbial activity and sulfate removal obtained for AUT cultures indicated that they possess the potential for use in local acid mine drainage decontamination processes.

摘要：生物法处理酸性矿山废水（acid mine drainage）的效果显著受接种物（inoculum）来源、pH值、化学需氧量/硫酸盐比（COD/sulfate ratio）及碳源影响。本研究针对用于硫酸盐还原的厌氧分批反应器（anaerobic batch reactors）的运行性能与微生物多样性（microbial diversity）展开评估。实验采用1.14±0.10的中等COD/硫酸盐比，评估分为两个阶段：阶段1以接种物来源为变量，设置本土接种物（autochthonous, AUT）与非本土接种物（non-autochthonous, N-AUT）两组；阶段2以碳源（乳酸盐、乙醇、甲酸盐）与低pH条件为变量。阶段1中，本土与非本土微生物群落的硫酸盐去除率分别为53%与59%，二者性能相近。阶段2中，中性pH条件下以乙醇、乳酸盐作为电子供体（electron donors）时，硫酸盐去除率分别为42%与44%，去除效果相当。当初始pH从4降至3时，以甲酸盐为碳源的体系硫酸盐去除率基本维持在34%；以乳酸盐为碳源的体系去除率从43%降至30%；以乙醇为碳源的体系去除率则从18%大幅降至7%。针对硫酸盐还原菌（sulfate-reducing bacteria）的变性梯度凝胶电泳（Denaturing gradient gel electrophoresis, DGGE）分析显示，所有受试样本中均存在该类细菌。本土接种物体系的微生物活性与硫酸盐去除效果表明，其具备应用于本地酸性矿山废水净化工艺的潜力。