The bioremediation of copper from distillery wastewater using indigenous microbes

Erosion of copper from the internal surface of the distillery vessels has been a major environmental concern mainly due to discharge of high concentrations of copper through drainage systems. The present study was designed to characterize the metal uptake and biosorption behaviour of indigenous microbes present and isolated from distillery environments. Bacillus licheniformis was isolated from distillery sump waters and identified using the API 50CH/B system. The minimum inhibitory concentration of copper against this organism ranged between 40-50mg/L. Biosorption capacities of B.licheniformis and a control laboratory strain B. subtilis 8045 for copper was determined using batch and continuous column experiments. Biosorption capacities for both strains was carried out at pH 5 and at copper concentrations of 10,50,70,90 and 200 mg/L. Immobilized bacterial studies of copper bioremediation were carried out with test and control strains using 2% calcium alginate beads to immobilize cells. Several parameters were optimized such as pH, bead size, and copper concentrations at which maximum biosorption can take place. Column bioreactor studies were done at an optimized pH and most efficient bead size and the effluent was collected at a flow rate of 1ml/min at every hour. Copper retention time in the immobilized column showed 90% removal bringing the copper levels down to below threshold levels in the first 10 hours of the column flow. The metal recovery was performed using 0.1M HCl and low pH solutions. The results of this study indicate the potential of bacterial copper bioremediation systems for distillery wastewaters.