The contribution of biotic and abiotic processes during azo dye reduction in anaerobic sludge

Autor: Jim A. Field, Valérie G Blanchard, Iemke Bisschops, Renske H. M. Bouwman, Gatze Lettinga, Frank P. van der Zee
Jazyk: angličtina
Rok vydání: 2003
Předmět:
Environmental Engineering
Sulfide
azo compounds
chemistry.chemical_element
Sulfides
system
Chemical reaction
Redox
Waste Disposal
Fluid
dyes
Bacteria
Anaerobic
anaërobe behandeling
rioolafvalwater
redox reactions
Bioreactor
Organic chemistry
anaerobic treatment
Water Pollutants
azoverbindingen
Biomass
Coloring Agents
bacteria
Waste Management and Disposal
Chemical decomposition
Water Science and Technology
Civil and Structural Engineering
chemistry.chemical_classification
WIMEK
afvalwaterbehandeling
Chemistry
Ecological Modeling
Biodegradation
kleurstoffen (dyes)
Pollution
Sulfur
decolorization
Anaerobic digestion
Kinetics
redox mediators
waste water treatment
redoxreacties
Textile Industry
sewage effluent
Environmental Technology
Milieutechnologie
Azo Compounds
Oxidation-Reduction
Nuclear chemistry
Zdroj: Water Research 37 (2003) 13
Water Research, 37(13), 3098-3109
ISSN: 0043-1354
Popis: Azo dye reduction results from a combination of biotic and abiotic processes during the anaerobic treatment of dye containing effluents. Biotic processes are due to enzymatic reactions whereas the chemical reaction is due to sulfide. In this research, the relative impact of the different azo dye reduction mechanisms was determined by investigating the reduction of Acid Orange 7 (AO7) and Reactive Red 2 (RR2) under different conditions. Reduction rates of two azo dyes were compared in batch assays over a range of sulphide concentrations in the presence of living or inactivated anaerobic granular sludgeAzo dye reduction results from a combination of biotic and abiotic processes during the anaerobic treatment of dye containing effluents. Biotic processes are due to enzymatic reactions whereas the chemical reaction is due to sulfide. In this research, the relative impact of the different azo dye reduction mechanisms was determined by investigating the reduction of Acid Orange 7 (AO7) and Reactive Red 2 (RR2) under different conditions. Reduction rates of two azo dyes were compared in batch assays over a range of sulphide concentrations in the presence of living or inactivated anaerobic granular sludge. Biological dye reduction followed zero order kinetics and chemical dye reduction followed second-order rate kinetics as a function of sulfide and dye concentration. Chemical reduction of the dyes was greatly stimulated in the presence of autoclaved sludge; whereas chemical dye reduction was not affected by living or gamma-irradiated-sludge. Presumably redox-mediating enzyme cofactors released by cell lysis contributed to the stimulatory effect. This hypothesis was confirmed in assays evaluating the chemical reduction of AO7 utilizing riboflavin, representative of the heat stable redox-mediating moieties of common occurring flavin enzyme cofactors. Sulfate influenced dye reduction in accordance to biogenic sulfide formation from sulfate reduction. In assays lacking sulfur compounds, dye reduction only readily occurred in the presence of living granular sludge, demonstrating the importance of enzymatic mechanisms. Both chemical and biological mechanisms of dye reduction were greatly stimulated by the addition of the redox-mediating compound, anthraquinone-disulfonate. Based on an analysis of the kinetics and demonstration in lab-scale upward-flow anaerobic sludge bed reactors, the relative importance of chemical dye reduction mechanisms in high rate anaerobic bioreactors was shown to be small due to the high biomass levels in the reactors. (C) 2003 Elsevier Science Ltd. All rights reserved.
Databáze: OpenAIRE
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