title: Improved dewatering of CEPT sludge by biogenic flocculant from Acidithiobacillus ferrooxidans.
abstract: Bioleaching using an iron-oxidizing bacterium, Acidithiobacillus ferrooxidans, and its biogenic flocculants was evaluated to improve the dewaterability of chemically enhanced primary treatment (CEPT) sewage sludge. CEPT sludge in flasks was inoculated with A. ferrooxidans culture, medium-free cells and the cell-free culture filtrate with and without the energy substance Fe(2+), and periodically the sludge samples were analysed for the dewaterability. This investigation proves that bioleaching effectively improved the sludge dewaterability as evidenced from drastic reduction in capillary suction time (≤20 seconds) and specific resistance to filtration (≥90%); however, it requires an adaptability period of 1-2 days. On the other hand, the biogenic flocculant produced by A. ferrooxidans greatly decreased the time-to-filtration and facilitated the dewaterability within 4 h. Results indicate that rapid dewatering of CEPT sludge by biogenic flocculants provides an opportunity to replace the synthetic organic polymer for dewatering.
authors.affiliation: Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong SAR, China E-mail: jwcwong@hkbu.edu.hk; Department of Biology, Hong Kong Baptist University, Hong Kong SAR, China.
authors.forename: Jonathan W C
authors.initials: JW
authors.lastname: Wong
authors.affiliation: Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong SAR, China E-mail: jwcwong@hkbu.edu.hk; Department of Environmental Science, Periyar University, Salem 636011, India.
authors.forename: Kumarasamy
authors.initials: K
authors.lastname: Murugesan
authors.affiliation: Department of Biology, Hong Kong Baptist University, Hong Kong SAR, China.
authors.forename: Shuk Man
authors.initials: SM
authors.lastname: Yu
authors.affiliation: Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong SAR, China E-mail: jwcwong@hkbu.edu.hk.
authors.forename: Mayur B
authors.initials: MB
authors.lastname: Kurade
authors.affiliation: Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Hong Kong SAR, China E-mail: jwcwong@hkbu.edu.hk; Department of Biology, Hong Kong Baptist University, Hong Kong SAR, China.
authors.forename: Ammaiyappan
authors.initials: A
authors.lastname: Selvam
mesh_terms: D042763:Acidithiobacillus / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D052918:Environmental Restoration and Remediation / Q000295:instrumentation / Q000379:methods*; D005374:Filtration; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000737:chemistry; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*
chemical_list: D011108:Polymers; D012722:Sewage