Sequencing polarity-inverting microbial fuel cell for wastewater treatment

A novel sequential polarity-inverting microbial fuel cell (MFC) is developed to neutralize anodic acidification and cathodic alkalinization and treat wastewater. The same electrode sequentially experiences anaerobic anode, aerobic cathode and anoxic cathode phases like a SBR (Sequencing Batch Reactor Activated Sludge process), and such two SBR half cells with opposite electrode polarities consist of a complete MFC. The system successfully buffers electrolyte and generates electricity with a maximum power density of 623 ± 4 mW/m3. Chemical oxygen demand is completely removed. Three bacteria, Arthrobacter sp., Stenotrophomonas sp. and Sphingobacterium sp., are found on the polarity-inverting electrode, and Arthrobacter sp. is believed to be capable of transferring electrons both to and from electrode. The proof-of-principle of a polarity-inverting MFC described here may offer an opportunity of integrating MFCs into the practical wastewater treating process.