Promotion effect of filamentous bacteria on removal of heavy metals during bioleaching from contaminated sediment
- Received Date: 05/12/2009
- Accepted Date: 27/10/2009
-
Key words:
- filamentous bacteria /
- low molecular weight organic acids /
- heavy metals /
- bioleaching /
- sediment
Abstract: The effect of co-inoculation of Acidithiobacillus ferrooxidans (A.f) and filamentous bacteria on the solubilization efficiency of Cu,Cd,Pb,Zn four kinds of heavy metals by bioleaching was studied in experiments. The results showed that bioleaching with the filamentous bacteria alleviated the inhibiton effect of low molecular weight organic acids on A.f and improved the solubilization efficiency of heavy metals. With 10% inoculum containing filamentous bacteria, pH of the sediment declined continuously down to 2.0 or less in 5 days and ferrous iron was completely oxidized in 4 days. Removal efficiencies of 76.3% for Cu, 92.5% for Cd, 52.6% for Pb, and 88.5% for Zn were obtained after 10 days of bioleaching. The period of bioleaching could be shortened by 1~2 days. As the removal efficiency increased by nearly 100 percent, the promotion effect on leaching out of Pb was the most evident in all four kinds of heavy metals. Hence, it is feasible that the filamentous bacteria might be used for bioleaching of sediment polluted by heavy metals-organics complex.