A fixed bed pervious concrete anaerobic bioreactor for biological sulphate remediation of acid mine drainage using simple organic matter

The development of low-operational-cost and low-operational-complexity active sulphate (SO₄ ) reducing bioremediation for Acid Mine Drainage (AMD) is an ongoing pursuit towards sustainable mining. This study introduces a fixed bed pervious concrete anaerobic bioreactor as a second stage AMD remediation process. The study investigated the pH self-regulation capabilities, SO₄ remediation capabilities and the rate limiting parameters of the bioreactor using glucose as an organic matter source. The AMD was pre-treated using a permeable reactive barrier. A 21-day trial comprised of an increase in the SO₄ loading rate while reducing the organic loading rate was undertaken to identify performance limiting conditions. A daily average SO₄ concentration reduction rate of 55.2% was achieved over the initial 13 days of the experiments. The study found that a COD to SO₄ ratio and VFA to alkalinity ratio below 5:1 and 0.5:1 respectively were performance limiting. The bioreactor was capable of self-regulating pH within the neutral range of 6.5 and 7.5. The study findings indicate that the bioreactor design can reduce operational costs and operational complexity of active AMD bioremediation.