Bioelectricity production from fermentable household waste in a dual-chamber microbial fuel cell

In this study, the use of a dual-chamber microbial fuel cell for the production of bioelectricity from a food residue biomass (FORBI) product was investigated. Food residue biomass was produced by drying and shredding the pre-sorted fermentable fraction of household food waste collected door-to-door in the Municipality of Halandri, Athens, Greece. Different organic loads of food residue biomass expressed as chemical oxygen demand (COD) were examined (0.7, 0.9, 1.4, 2.8, 6 and 14 g COD L-1, respectively). It was observed that an increase of the initial concentration of the final extract resulted in a corresponding increase in the operating time. The microbial fuel cell potential increased from 33.3 mV to 46 mV as the concentration was increased from 0.7 to 14 g COD L-1. The best performance in terms of maximum power density (29.6 mW m-2) corresponding to a current density of 88 mA m-2 was observed for 6 g COD L-1. Setting the external resistance at its optimal value (Rext = 2 kΩ) as determined by polarisation experiments, Pyield drastically increased to 13.7 and 17.3 Joule (g FORBI)-1 in two consecutive cycles. The results demonstrate that readily biodegradable substrates, such as food residue biomass, can be effectively used for enhanced bioelectricity harvesting in a microbial fuel cell.