Continuous electricity generation from domestic wastewater and organic substrates in a flat plate microbial fuel cell.
A microbial fuel cell (MFC) is a device that converts organic matter to electricity using microorganisms as the biocatalyst. Most MFCs contain two electrodes separated into one or two chambers that are operated as a completely mixed reactor. In this study, a flat plate MFC (FPMFC) was designed to operate as a plug flow reactor (no mixing) using a combined electrode/proton exchange membrane (PEM) system. The reactor consisted of a single channel formed between two nonconductive plates that were separated into two halves by the electrode/PEM assembly. Each electrode was placed on an opposite side of the PEM, with the anode facing the chamber containing the liquid phase and the cathode facing a chamber containing only air. Electricity generation using the FPMFC was examined by continuously feeding a solution containing wastewater, or a specific substrate, into the anode chamber. The system was initially acclimated for 1 month using domestic wastewater orwastewater enriched with a specific substrate such as acetate. Average power density using only domestic wastewater was 72+/-1 mW/m2 at a liquid flow rate of 0.39 mL/min [42% COD (chemical oxygen demand) removal, 1.1 h HRT (hydraulic retention time)]. At a longer HRT = 4.0 h, there was 79% COD removal and an average power density of 43+/-1 mW/m2. Power output was found to be a function of wastewater strength according to a Monod-type relationship, with a half-saturation constant of Ks = 461 or 719 mg COD/L. Power generation was sustained at high rates with several organic substrates (all at approximately 1000 mg COD/L), including glucose (212+/-2 mW/ m2), acetate (286+/-3 mW/m2), butyrate (220+/-1 mW/ m2), dextran (150+/-1 mW/m2), and starch (242+/-3 mW/ m2). These results demonstrate the versatility of power generation in a MFC with a variety of organic substrates and show that power can be generated at a high rate in a continuous flow reactor system.
Min
Booki
B
Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Logan
Bruce E
BE
D001674:Bioelectric Energy Sources; D003246:Conservation of Energy Resources; D003911:Dextrans / Q000032:analysis; D004560:Electricity; D004566:Electrodes; D009930:Organic Chemicals / Q000302:isolation & purification; D010100:Oxygen / Q000032:analysis / Q000378:metabolism; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013213:Starch / Q000032:analysis; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
D003911:Dextrans; D009930:Organic Chemicals; D012722:Sewage; D013213:Starch; D010100:Oxygen