Using 3D Composite Electrode Materials for Electricity Generation from Swine Wastewater in a Dual-Chamber Microbial Fuel Cells

Abstract

Swine wastewater has a high concentration of organic matter, suspended solids, and higher ammonia nitrogen, odor, complex polluting ingredients, and large emissions. A two-chambered cubic microbial fuel cell (MFC) was used to evaluate the effect of a novel three-dimensional (3D) electrode made of 3D iron composites and 3D stainless composites on the electricity generation. Swine wastewater with a total chemical oxygen demand (TCOD) of 3688 ± 300 mg/L was used as the feedstock in the anode chamber. The MFC reactor was incubated with an initial pH of 7.0 in an air shaker with a temperature of ~35°C and 100 rpm in the fed-batch mode. A fixed external resistance (R) of 100 Ω was connected between the electrodes, and the closed-circuit potentials of the MFCs were recorded every 5 min. The results showed that using an iron–carbon fiber composite 3D electrode resulted in a peak electricity generation of 321 mV on the first 2 days and maintained a stable voltage of 163 mV during the second to sixth days. The COD removal efficiency could reach 75%. Using a stainless–carbon fiber 3D electrode could generate a peak voltage of only 29.5 mV and a stable voltage of 15.2 mV with a COD removal efficiency of 54%.