Efficacy of Microbial Fuel Cell for bioelectricity generation and pollutant reduction at different CODs of sugar beet processing wastewater

Abstract

<b><sc>Abstract.</sc></b> Microbial fuel cell (MFC) has shown promise in producing bioelectricity and simultaneously reducing pollutants from wastewater. In this study, dual-chamber MFCs were used to evaluate the efficacy of MFC for simultaneous bioelectricity generation and pollutant reduction from sugar beet processing wastewater (SBWW) at varying Chemical Oxygen Demand (COD) levels. Pretreated Nafion was used as a cation exchange membrane (CEM), and carbon-cloth was used as electrode. Three different substrate COD levels (e.g., 1373±40, 1960±56 and 3570±20mg/L) were selected to see the efficacy of MFC. Monobasic potassium phosphate (50 mM) with pH 7.0±0.2 was used as catholyte. Both before and after experiment substrates were analyzed for electrical conductivity (EC), pH, COD and Inductively Coupled Plasma (ICP) analysis. Additionally, colony forming units (CFU) were done with substrate before the experiment and scanning electron microscopy (SEM) analysis was done on anode samples after an experiment. Bioelectricity output was recorded using the CR1000 datalogger. Maximum of 726.2±19.2, 719.9±13.1, and 752.9±32.6mV bioelectricity were generated from these three COD levels, respectively. Overall, maximum current density was 414.4±95.7, 490±75.8 and 233±17.2mA/m², power density 10.6±4.2, 13.8±5 and 4.1±0.9mW/m² and Coulombic Efficiency (CE) 1.8%, 2.1% and 3.5% were noted for three COD levels, respectively. Overall, MFC with substrate COD level 2 (with COD 1960±56 mg/L) resulted in better current density, power density, CE, and reduce more substrate pollutants compare to other two COD levels. In this study, approximately 90% COD, 65% of TOC, 50% iron, 41% of nitrogen reduction were observed from MFC with substrate COD level 1960±56mg/L.