Biological removal of zinc from wastewater using Aspergillus sp

The present study was conducted on removal of zinc in a continuous flow system by Aspergillus sp. during its growth. The fungal strain was isolated from industrial wastewater. The experiments under continuous culture conditions were performed in two reactors of working volume 650ml and 3 litres respectively. The experiments were conducted using sugar concentrations of 10, 15 and 20g/l and at dilution rates of 0.08, 0.04 and 0.02h. Specific zinc uptake of 44mg and 77mg per gram dry biomass were obtained in 650ml and 3 litre reactors, at 10g/l sugar concentration and 0.02h dilution rate. No significant increase was observed in the specific zinc uptake with increase in sugar concentration. The specific uptake of zinc increased to 79mg/g of dry biomass at 15g/l sugar concentration and to 84mg/g of dry biomass at the same sugar concentration but with proportional increase in nutrient components . At higher initial concentration (1000mg/l) of zinc, the specific zinc uptake by the fungus was found to be 120mg/g of dry biomass at 10g/l sugar concentration. Further studies using an actual industrial effluent having zinc concentration of 46mg/l resulted in a complete removal of the metal at 10g/l sugar concentration. © 2003 SDU. All rights reserved.