EJMP&EP


Technical Note


Biological removal of zinc from wastewater using Aspergillus sp.

S. Sharma1, M.G. Dastidar1* and T.R. Sreekrishnan2

1 Centre for Energy Studies
2 Department of Biochemical Engineering and Biotechnology Indian Institute of Technology, Hauz Khas, New Delhi-110016, India


Received 13 June 2002; accepted 3 January 2003




ABSTRACT

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-1. Specific zinc uptake of 44mg and 77mg per gram dry biomass were obtained in 650ml and 3 litres reactors, at 10g/l sugar concentration and 0.02h-1 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.


Keywords: Zinc; Aspergillus sp.; Specific metal uptake; Continuous flow system



* Corresponding author
   E-mail : dastidar@ces.iitd.ernet.in