title: Influence of ferrous ions on extracellular polymeric substances content and sludge dewaterability during bioleaching.
abstract: Pretreatment of activated sludge with sulfuric acid and bioleaching using Acidithiobacillus ferrooxidans along with addition of Fe(2+) on sludge dewaterability was investigated. The sludge dewatering efficiency in terms of capillary suction time (CST) and specific resistant to filtration (SRF) was increased with a decrease in sludge pH. A pH of 2.67 was found to be optimum for dewatering, at which 81% and 63% reduction of CST and SRF were achieved, respectively. The dewaterability of sludge was enhanced after the addition of Fe(2+) and A. ferrooxidans. Ideal concentration of Fe(2+) was 2 g/L for sludge dewaterability, which showed 96% and 88% reduction in CST and SRF, respectively. In the control sludge, maximum part of the biopolymeric macromolecules was contributing by the tightly bound extracellular polymeric substances (TB-EPS). At optimum Fe(2+) concentration, total EPS was reduced by 73%, enhancing sludge dewaterability. Bioleaching conducted by A. ferrooxidans could solubilized 88% Cu and 99% Zn within 120 h.
authors.affiliation: Sino Forest Applied Research Center for Pearl River Delta Environment & Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region. Electronic address: jwcwong@hkbu.edu.hk.
authors.forename: Jonathan W C
authors.initials: JWC
authors.lastname: Wong
authors.affiliation: Sino Forest Applied Research Center for Pearl River Delta Environment & Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region; College of Resources and Environment, Nanjing Agricultural University, Nanjing, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Sino Forest Applied Research Center for Pearl River Delta Environment & Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region.
authors.forename: Mayur B
authors.initials: MB
authors.lastname: Kurade
authors.affiliation: Sino Forest Applied Research Center for Pearl River Delta Environment & Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region.
authors.forename: Kumarasamy
authors.initials: K
authors.lastname: Murugesan
mesh_terms: D042763:Acidithiobacillus / Q000187:drug effects / Q000378:metabolism; D001426:Bacterial Proteins / Q000032:analysis; D001673:Biodegradation, Environmental / Q000187:drug effects; D001704:Biopolymers / Q000032:analysis*; D003300:Copper / Q000302:isolation & purification; D005110:Extracellular Space / Q000737:chemistry; D005374:Filtration; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007501:Iron / Q000494:pharmacology*; D011134:Polysaccharides / Q000032:analysis; D012722:Sewage / Q000737:chemistry*; D013997:Time Factors; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D015032:Zinc / Q000302:isolation & purification
chemical_list: D001426:Bacterial Proteins; D001704:Biopolymers; D007477:Ions; D011134:Polysaccharides; D012722:Sewage; D014874:Water Pollutants, Chemical; D014867:Water; D003300:Copper; D007501:Iron; D015032:Zinc
keywords: Acidithiobacillus ferrooxidans; Bioleaching; Extracellular polymeric substances; Sewage sludge; Sludge dewaterability