Effect of carbon source and metal toxicity for potential acid mine drainage (AMD) treatment with an anaerobic sludge using sulfate-reduction

摘要

This study compares sulfate-reduction performance in an anaerobic sludge with different carbon sources (ethanol, acetate, and glucose). Also, the toxic effect of copper was evaluated to assess its feasibility for possible AMD treatment. Serological bottles with 1.5 g VSS/L and 150 mL of basal medium (0.67 g COD/g SO42- at a 7-8 pH) were used to determine the percentage of electron equivalents, maximum specific methanogenic (SMA), and sulfide generation activities (SGA). The copper effect was evaluated in a previously activated sludge in batch bioassays containing different concentrations of copper (0-50 mg/L), 3 gVSS/L, and 150 mL of basal medium (0.67 g COD/g SO42-). Carbon source bioassays with glucose obtained the best results in terms of the SGA (1.73 0.34 mg S2-/g VSS center dot d) and SMA (10.41 mg COD-CH4/g VSS center dot d). The electron flow in the presence of glucose also indicated that 21.29 5.2 of the metabolic activity of the sludge was directed towards sulfidogenesis. Copper toxicity bioassays indicated that a considerable decline in metabolic activity occurs above 10 mg/L. The 20IC, 50IC, and 80IC were 4.5, 14.94, 35.31 mg Cu/L. Compared to the other carbon sources tested, glucose proved to be a suitable electron donor since it favors sulfidogenesis. Finally, copper concentrations above 15 mg/L inhibited metabolic activity in the toxicity bioassays. HIGHLIGHTS The influence of organic matter degradation and copper toxicity was assessed. Potential application of SRB for acid mine drainage treatment was evaluated. The highest sulfidogenic activity was observed with glucose as carbon source. High copper concentration impacts sulfate removal and sulfide production.