Comparison of the performance of microbial fuel cell for treatment of different vegetable liquids and potato solid with different sizes

Abstract

Experiments of MFC for treating liquids of potato, tomato and lettuce as well as potato cubes with different edge lengths of 3, 5 and 7 mm were conducted, and the differences in the removal of organic matter and electricity generation were evaluated. For all three vegetable liquids, organic matter contained was effectively removed (the final removal for COD was 89.6-93.2 %), with slight differences being appeared only in the initial several days. The current density (72.2-100.2 mA/m 2) followed the order of potato > tomato > lettuce, while the columbic efficiency varied slightly (15.6-17.3 %). For potato cubes with three different sizes, the obtained results showed the final removal for total COD could reach 88.0-91.8 %, with the cubes of 7 mm revealing a comparatively slower removal rate in the first half of the whole operation for 81 days. The corresponding current density was found to be in the range of 163.3-189.1 mA/m 2 and the columbic efficiency in the range of 51.5-63.9 %, both following the order of 3 mm > 5 mm > 7 mm. The findings of this study are considered useful for optimization of the composition of vegetable waste, which is normally consisted of liquids and solids of different vegetable types, for treatment by MFCs.