Effect of Substrates on Bioleaching of Heavy Metals from Thickened Sludge
Bioleaching of heavy metals from thickened wastewater sludge with different substrates was studied with indigenous Thiobacillus isolated from native sludge and enriched by selected mediums. Results showed that removal of heavy metals with mixed substrate of FeSO4.7H2O and S was better than that with only S or FeSO4.7H2O. The leaching of Zn and Cu was accelerated with mixed substrate of FeSO4.7H2O and S. After 14 day bioleaching, removal of Zn and Cu reached 77.9% and 57.5%. During experiments, VS in the sludge decreased and 38.3%～59.9% of nitrogen and 43.3%～62.1% of phosphorous were lost because of long time acidification.