title: Ferrous sulphate oxidation using Thiobacillus ferrooxidans cells immobilised on sand for the purpose of treating acid mine-drainage.
abstract: Thiobacillus ferrooxidans was immobilised on sand (size 0.85 mm to 1.18 mm) for use in a repeated batch and continuously operated packed-bed bioreactor which has not been previously reported in the literature. Repeated batch operation resulted in the complete oxidation of ferrous to ferric iron. The bacteria were active immediately after 3-4 weeks in a non-aqueous medium; i.e. the sand was allowed to dry out, demonstrating the stability of the system. A lag phase of 28 days was recorded when the sand was stored dried in a sealed container for 16 weeks compared with a lag phase of 13 days for a sample frozen for 18 weeks. After a period of 10 days, continuous operation of the reactor at a dilution rate of 0.64 h(-1) resulted in 95-99% oxidation of ferrous iron or 0.31-0.33 kg m(-3) h(-1). With the use of a scanning electron microscope, images were recorded of Thiobacillus ferrooxidans on sand.
authors.affiliation: Department of Mechanical and Chemical Engineering, Heriot-Watt University, Riccarton, Edinburgh, UK.
authors.forename: T A
authors.initials: TA
authors.lastname: Wood
authors.forename: K R
authors.initials: KR
authors.lastname: Murray
authors.forename: J G
authors.initials: JG
authors.lastname: Burgess
mesh_terms: D000327:Adsorption; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D018914:Cells, Immobilized; D005296:Ferrous Compounds / Q000378:metabolism*; D019216:Metals, Heavy; D008855:Microscopy, Electron, Scanning; D008906:Mining; D010084:Oxidation-Reduction; D012822:Silicon Dioxide; D013855:Thiobacillus / Q000166:cytology* / Q000254:growth & development / Q000378:metabolism; D014865:Waste Disposal, Fluid; D014876:Water Pollution
chemical_list: D005296:Ferrous Compounds; D019216:Metals, Heavy; C020748:ferrous sulfate; D012822:Silicon Dioxide