title: Bioleaching of chromium from tannery sludge by indigenous Acidithiobacillus thiooxidans.
abstract: Chromium in tannery sludge will cause serious environmental problems and is toxic to organisms. The acidophilic sulfur-oxidizing Acidithiobacillus thiooxidans can leach heavy metals form urban and industrial wastes. This study examined the ability of an indigenous sulfur-oxidizing A. thiooxidans to leach chromium from tannery sludge. The results showed that the pH of sludge mixture inoculated with the indigenous A. thiooxidans decreased to around 2.0 after 4 days. After 6 days incubation in shaking flasks at 30 degrees C and 160 rpm, up to 99% of chromium was solubilized from tannery sludge. When treated in a 2-l bubble column bioreactor for 5 days at 30 degrees C and aeration of 0.5 vvm, 99.7% of chromium was leached from tannery sludge. The results demonstrated that chromium in tannery sludge can be efficiently leached by the indigenous A. thiooxidans.
authors.affiliation: College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, PR China.
authors.forename: Yuan-Shan
authors.initials: YS
authors.lastname: Wang
authors.forename: Zhi-Yan
authors.initials: ZY
authors.lastname: Pan
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Lang
authors.forename: Jian-Miao
authors.initials: JM
authors.lastname: Xu
authors.forename: Yu-Guo
authors.initials: YG
authors.lastname: Zheng
mesh_terms: D013856:Acidithiobacillus thiooxidans / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002857:Chromium / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000517:prevention & control; D012722:Sewage / Q000382:microbiology*
chemical_list: D007220:Industrial Waste; D012722:Sewage; D002857:Chromium