Complete degradation of the azo dye Acid Orange-7 and bioelectricity generation in an integrated microbial fuel cell, aerobic two-stage bioreactor system in continuous flow mode at ambient temperature.
In this study, the commercially used model azo dye Acid Orange-7 (AO-7) was fully degraded into less toxic intermediates using an integrated microbial fuel cell (MFC) and aerobic bioreactor system. The integrated bioreactor system was operated at ambient temperature and continuous-flow mode. AO-7 loading rate was varied during experiments from 70gm(-3)day(-1) to 210gm(-3)day(-1). Colour and soluble COD removal rates reached>90% under all AO-7 loading rates. The MFC treatment stage prompted AO-7 to undergo reductive degradation into its constituent aromatic amines. HPLC-MS analysis of metabolite extracts from the aerobic stage of the bioreactor system indicated further oxidative degradation of the resulting aromatic amines into simpler compounds. Bioluminescence based Vibrio fischeri ecotoxicity testing demonstrated that aerobic stage effluent exhibited toxicity reductions of approximately fivefold and ten-fold respectively compared to the dye wastewater influent and MFC-stage effluent.
Faculty of Science and Technology, Applied Biotechnology Research Group, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK. Electronic address: eustace.fernando@my.westminster.ac.uk.
Eustace
E
Fernando
Faculty of Science and Technology, Applied Biotechnology Research Group, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK. Electronic address: t.keshavarz@my.westminster.ac.uk.
Taj
T
Keshavarz
Faculty of Science and Technology, Applied Biotechnology Research Group, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK. Electronic address: g.kyazze@my.westminster.ac.uk.
Godfrey
G
Kyazze
D000332:Aerobiosis / Q000187:drug effects; D048908:Aliivibrio fischeri / Q000187:drug effects; D000588:Amines / Q000302:isolation & purification; D001391:Azo Compounds / Q000302:isolation & purification* / Q000633:toxicity; D001557:Benzenesulfonates / Q000302:isolation & purification* / Q000633:toxicity; D001673:Biodegradation, Environmental / Q000187:drug effects; D001674:Bioelectric Energy Sources; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D003116:Color; D004396:Coloring Agents / Q000302:isolation & purification*; D012995:Solubility; D013696:Temperature; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry
D000588:Amines; D001391:Azo Compounds; D001557:Benzenesulfonates; D004396:Coloring Agents; D062065:Wastewater; C014722:2-naphthol orange
Azo dye; Biodegradation; Detoxification; Integrated bioreactor; Microbial fuel cell