Potential of autochthonous sulfate-reducing microbial communities for treating acid mine drainage in a bench-scale sulfidogenic reactor

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 biom asses 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%, wher eas 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 t hey possess the potential for use in local acid mine drainage decontamination processes.
Source: Brazilian Journal of Chemical Engineering - Category: Chemistry Source Type: research