ALTERNATIVE ENERGY SUBSTRATES FOR BACTERIAL LEACHING OF HEAVY-METALS FROM SEWAGE-SLUDGE

Bacterial leaching of heavy metals from sewage sludge with different iron containing compounds as energy substrates was studied in a batch system using a culture of Thiobacillus ferrooxidans. It was proven that spent FeSO4.7H2O and pyrite met the criteria of an energy substrate and could be substituted for reagent grade FeSO4.7H2O. This substitution could significantly reduce energy substrate cost: 99% with spent FeSO4.7H2O and 94% with pyrite. The solid aspect of pyrite compromises its use.