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Sulfate supplements enhance the decolorization of an azo dye acid red 18 in anaerobic baffled reactors

Authors

  • Benjaporn Boonchayaanant,

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    1. Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
    2. Center of Excellence for Environmental and Hazardous Waste Management (EHWM), Bangkok 10330, Thailand
    • Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand. E-mail: benjaporn.bo@chula.ac.th

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  • Suppakit Wangsaviboon,

    1. Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
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  • Wiboonluk Pungrasmi,

    1. Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
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  • Sutha Khaodhiar

    1. Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand
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Abstract

This study investigates the effects of sulfate on biological azo dye decolorization in anaerobic baffled reactors (ABRs) using Acid Red 18 as a model azo dye. The ABRs supplemented with sulfate at chemical oxygen demand (COD):sulfate ratios of 2.5 and 0.6 had the decolorization efficiencies of (89.4 ± 3.62)% and (89.9 ± 5.50)%, respectively. These were significantly greater than the decolorization efficiency of the ABR without sulfate supplements that had the decolorization efficiency of (76.7 ± 5.14)%. The primary decolorization mechanisms in the ABR with no sulfate added and the ABR with the COD:sulfate ratio of 2.5 were biological and required the presence of cells. By contrast, the azo dye decolorization in the ABR with the COD:sulfate ratio of 0.6 can occur to a great extent in the absence of cells, suggesting the role of extracellular mechanisms on azo dye decolorization under this condition. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1045–1054, 2013

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