Electricity Generation from Artificial Wastewater Using an Upflow Microbial Fuel Cell

Abstract

The upflow microbial fuel cell (UMFC) was developed to generate electricity while simultaneously treating wastewater. During a five-month period of feeding a sucrose solution as the electron donor, the UMFC continuously generated electricity with a maximum power density of 170 mW/m2. To achieve this power density, the artificial electron-mediator hexacyanoferrate was required in the cathode chamber. The power density increased with increasing chemical oxygen demand (COD) loading rates up to 2.0 g COD/ L/day after which no further increases in power density were observed, indicating the presence of limiting factors. The overarching limiting factor for the UMFC in this study was the internal resistance, which was estimated as 84 omega at the maximum power density, and restricted the power output by causing a significant decrease in operating potential. Low Coulombic efficiencies varying from 0.7 to 8.1% implied that the electron-transfer bacteria were incapable of converting all of the available organics into electricity, so the excessive substrate created niches for the growth of methanogens. We found that the soluble COD (SCOD) removal efficiencies remained over 90% throughout the operational period, mainly because of methanogenic activity, which accounted for 35 to 58% of the SCOD removed at a loading rate of 1.0 g COD/L/ day. Additionally, transport limitation due to insufficient substrate diffusion was shown by cyclic voltammetry (CV).

The continued development of reticulated vitreous carbon as a versatile electrode material: Structure, properties and applications

“…Electricity generation from artificial wastewater using an upward flow microbial fuel cell has also been considered [25]. Cylindrical anodes, made of grade 10 and 20 ppi RVC, had a volume of 190 dm 3 .…”

Microtoming coupled to microarray analysis to evaluate the spatial metabolic status of Geobacter sulfurreducens biofilms

“…A potential limitation on the metabolism for cells closer to the anode surface is lack of electron donor or nutrients due to cells in the outer section consuming these components (He et al, 2005;Marcus et al, 2007;Rabaey et al, 2007;Torres et al, 2008). G. sulfurreducens genes encoding acetate transporters that are more highly expressed when acetate is limiting have been identified (Risso et al, 2008).…”

Optimizing the electrode size and arrangement in a microbial electrolysis cell

“…However, the application of the MEC technology to wastewater treatment requires further research to improve the design and develop inexpensive electrode materials with a high specific surface area, good conductivity, and a high stability. Several anode materials have been recently tested in MECs, including graphite granules, reticulate vitreous carbon, carbon foam, and graphite brush electrodes (Aelterman et al, 2006;Chaudhuri and Lovley, 2003;He et al, 2005;Logan et al, 2007;Zuo et al, 2007). The benefits of three dimensional (3D) anodes, which provide increased surface area for microbial attachment (Aelterman et al, 2008;Logan et al, 2007;Zhang et al, 2011), have been demonstrated by comparing a packed bed of irregular graphite granules with three different thicknesses to a one-dimensional configuration (Di Lorenzo et al, 2010).…”