Bio-Remediation of Acid Mine Drainage in the Sarcheshmeh Porphyry Copper Mine by Fungi: Batch and Fixed Bed Process

Abstract

Acid mine drainage (AMD) containing high concentrations of iron and sulphate, low pH and variable concentrations of heavy metals leads to many environmental problems. The concentrations of Cu and Mn are high in the AMD of the Sarcheshmeh porphyry copper mine, Kerman province, south of Iran. In this study, the bio-remediation of Cu and Mn ions from acid mine drainage was investigated using two native fungi called Aspergillus niger and Phanerochaete chrysosporium which were extracted from the soil and sediment samples of the Shour River at the Sarcheshmeh mine. The live fungi was first harvested and then killed by boiling in 0.5 N NaOH solution. The biomass was finally dried at 60 C  for 24 h and powdered. The optimum biosorption parameters including pH, temperature, the amount of biosorbent and contact time were determined in a batch system. The optimum pH varied between 5 and 6. It was found that the biosorption process increased with an increase in temperature and the amount of biosorbent. Biosorption data were attempted by Langmuir and Freundlich isotherm models and showed a good match. Kinetic studies were also carried out in the present study. The results show that the second-order kinetics model fits well the experimental data. The biosorption experiments were further investigated with a continuous system to compare the biosorption capacities of two systems. The results show that biosorption process using a continuous system increases efficiency up to 99%. A desorption process was eventually performed in order to recover Copper and Manganese ions. This process was successful and fungi could be used again.