Effect of Food Waste Condensate Concentration on the Performance of Microbial Fuel Cells with Different Cathode Assemblies

The aim of this study is to examine the effect of food waste condensate concentration (400-4000 mg COD/L) on the performance of two microbial fuel cells (MFCs). Food waste condensate is produced after condensing the vapors that result from drying and shredding of household food waste (HFW). Two identical single-chamber MFCs were constructed with different cathodic assemblies based on GoreTex cloth (Cell 1) and mullite (Cell 2) materials. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) measurements were carried out to measure the maximum power output and the internal resistances of the cells. High COD removal efficiencies (>86%) were observed in all cases. Both cells performed better at low initial condensate concentrations (400-600 mg COD/L). Cell 1 achieved maximum electricity yield (1.51 mJ/g COD/L) at 500 mg COD/L and maximum coulombic efficiency (6.9%) at 400 mg COD/L. Cell 2 achieved maximum coulombic efficiency (51%) as well as maximum electricity yield (25.9 mJ/g COD/L) at 400 mg COD/L. Maximum power was observed at 600 mg COD/L for Cell 1 (14.2 mW/m(2)) and Cell 2 (14.4 mW/m(2)). Impedance measurements revealed that the charge transfer resistance and the solution resistance increased significantly with increasing condensate concentration in both cells.