In this study, three biological sand filters (BSF) were contaminated with a synthetic iron- [1500 mg.L(-1) Fe(II), 500 mg.L(-1) Fe(III)] and sulphate-rich (6000 mg.L(-1) SO4 (2-) ) acid mine drainage (AMD) (pH=2), for 24 days, to assess the remediation capacity and the evolution of autochthonous bacterial communities (monitored by T-RFLP and 16S rRNA gene clone libraries). To stimulate BSF bioremediation involving sulphate-reducing bacteria, a readily degradable carbon source (glucose, 8000 mg.L(-1) ) was incorporated to the influent AMD. Complete neutralization and average removal efficiencies of 81.5 (± 5.6)%, 95.8 (± 1.2)% and 32.8 (± 14.0)% for Fe(II), Fe(III) and sulphate were observed, respectively. Our results suggest that microbial iron- and sulphate-reduction associated with iron precipitation were the main processes contributing to AMD neutralization. The effect of AMD on BSF sediment bacterial communities was highly reproducible. There was a decrease in diversity, and notably a single dominant operational taxonomic unit (OTU), closely related to Clostridium beijerinckii, which represented up to 65% of the total community at the end of the study period. This article is protected by copyright. All rights reserved.