title: Molasses as an efficient low-cost carbon source for biological Cr(VI) removal.
abstract: In the present study, indigenous microorganisms from industrial sludge were used to reduce the activity of Cr(VI). Molasses, a by-product of sugar processing, was selected as the carbon source (instead of sugar used in a previous work) as it is a low-cost energy source for bioprocesses. Initially, experiments were carried out in suspended growth batch reactors for Cr(VI) concentrations of 1.5-110 mg/L. The time required for complete Cr(VI) reduction increased with initial Cr(VI) concentration. Initial molasses concentration was also found to influence the Cr(VI) reduction rate. The optimal concentration for all initial Cr(VI) concentrations tested was 0.8 gC/L. Experiments were also carried out in packed-bed reactors. Three different operating modes were used to investigate the optimal performance and efficiency of the filter, i.e. batch, continuous and SBR with recirculation. The latter mode with a recirculation rate of 0.5L/min lead to significantly high Cr(VI) reduction rates (up to 135 g/m(2)d). The results of this work were compared with those of a similar work using sugar as the carbon source and indicate that molasses could prove a feasible technological solution to a serious environmental problem.
authors.affiliation: Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio, Greece.
authors.forename: Michail K
authors.initials: MK
authors.lastname: Michailides
authors.affiliation: Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio, Greece. Electronic address: atekerle@upatras.gr.
authors.forename: Athanasia G
authors.initials: AG
authors.lastname: Tekerlekopoulou
authors.affiliation: Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio, Greece.
authors.forename: Christos S
authors.initials: CS
authors.lastname: Akratos
authors.affiliation: Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio, Greece.
authors.forename: Sandra
authors.initials: S
authors.lastname: Coles
authors.affiliation: Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou Str., Platani, P.O. Box 1414, GR-26504 Patras, Greece; Department of Chemical Engineering, University of Patras, GR-26504 Patras, Greece.
authors.forename: Stavros
authors.initials: S
authors.lastname: Pavlou
authors.affiliation: Department of Environmental and Natural Resources Management, University of Patras, 2 G. Seferi Str., GR-30100 Agrinio, Greece; Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Stadiou Str., Platani, P.O. Box 1414, GR-26504 Patras, Greece.
authors.forename: Dimitrios V
authors.initials: DV
authors.lastname: Vayenas
mesh_terms: D019149:Bioreactors; D002244:Carbon; D002857:Chromium / Q000378:metabolism*; D007220:Industrial Waste; D008965:Molasses; D010084:Oxidation-Reduction; D012722:Sewage; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000379:methods
chemical_list: D007220:Industrial Waste; D012722:Sewage; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D002244:Carbon
keywords: Attached growth; Biological removal; Hexavalent chromium; Molasses; Suspended growth