A microbial fuel cell (MFC) is defined as a device which uses microorganisms as the biocatalyst to convert the organic matter to electricity. In recent year’s MFCs gained tremendous interest for achieving simultaneous power production and recalcitrant wastewaters treatment.
In this study, a dual chamber MFC was designed to examine simultaneous electricity generation and poly-azo dye (Sirius Red) decolorization using brewery waste as a cheap carbon source. The experimental results showed a
stable voltage production of 0.39±0.025 V (~1.7-1.9 mA at 220 Ω external resistor) using brewery wastewater as a carbon source and with the addition of Sirius Red azo dye. The maximum power density achieved was 276±19 W/m2 at an initial brewery waste chemical oxygen deman(COD) of ~1000 mg/L with and without addition of dye (200 mg/L). In Fourier Transform Infrared study, disappearance of the peak at 1643.12 cm-1 in the product spectra in comparison to the control dye confirmed the removal of the azo bond during dye degradation. Gas chromatography-mass spectrometry showed sodium-4-aminoazobenzene-4''-sulfonate to be the subsequent metabolite formed during
the decolorization of Sirius Red. A decolorization efficiency of 2.22 mg/L/h was attained in the anode chamber and COD removal was 90 and 61.7% for brewery wastewater before and after addition of dye in 48 h batch studies, respectively. Dye removal was decreased with the increase in dye initial concentrations (25-200 mg/L) and increased notably with the increase in glucose initial concentration between 0 to 2000 mg/L. Cyclic voltammetry
showed peaks in the electrode with biofilm in MFC solution and no peak for electrode without biofilm in fresh MFC medium, which indicated the presence of membrane-associated electron shuttles. Scanning electron microscopy images revealed that the anode biofilm in the MFC comprised of mainly rod-shaped cells that were firmly attached on the anode surface. These results demonstrate the potential of azo dye-containing wastewater and easily
biodegradable carbon-based wastewater’s simultaneous treatment in MFCs along with current generation.