Influence of nitrogen limitation on performance of a microbial fuel cell

摘要

We describe the operation of a microbial fuel cell (MFC) system operating on a syntheticnwastewater (acetic acid), under conditions of increasing nitrogen limitation. Two MFCs werenoperated under feed conditions which spanned a range of TKN/COD values of 1.6–28 mg/g.nStable operation was observed in all cases, even when no ammoniacal nitrogen was added tonthe cell. Improved electrochemical performance (measured as power density, W/m2) wasnobserved as nitrogen limitation was imposed on the cells. Even with no ammonium addition,ncontinuous function of the cell was maintained, at levels consistent with operation at balancednnutrient supplementation. The work has implicated biological nitrogen fixation as a potentialnsource of nitrogen within the MFC. Whilst this hypothesis has yet to be confirmed, the worknhighlights the opportunity for continuous operation of microbial fuel cells utilising wastewatersnwith extremely low nitrogen levels, present in pulp and paper, pharmaceutical and petrochemicalnindustries. Further, the described increases in some of the electrochemical indices (e.g. powerndensity) under application of nitrogen limitation may provide a new approach to increasing fuelncell performance. Finally, the lack of any need to add supplemental nitrogen to a MFC-basednwastewater treatment technology holds potential for significant financial and environmentalnsavings.