Power generation and contaminant removal in single chamber microbial fuel cells (SCMFCs) treating human urine

The potential of single chamber microbial fuel cells (SCMFC) to treat raw, fresh human urine was investigated. The power generation (55 μW) of the SCMFCs with platinum (Pt)-based cathode was higher than those with Pt-free cathodes (23 μW) at the beginning of the tests, but this difference decreased over time. Up to 75% of the chemical oxygen demand (COD) in urine was reduced after a 4-day treatment. During this time, the ammonium concentration increased significantly to 5 gNH4+-N/L in SCMFCs due to urea hydrolysis, while sulfate concentration decreased and transformed into H2S due to sulfate reduction reactions. Calcium and magnesium concentrations dropped due to precipitation at high pH, and phosphorous decreased 20–50% due to the formation of struvite that was found on the cathode surface and on the bottom of the anodic chamber. The advantages of power generation, COD removal, and nutrient recovery make SCMFCs treating human urine a cost-effective biotechnology.