Influence of nitrogen limitation on performance of a microbial fuel cell

Zusammenfassung

We describe the operation of a microbial fuel cell (MFC) system operating on a synthetic wastewater (acetic acid), under conditions of increasing nitrogen limitation. Two MFCs were operated under feed conditions which spanned a range of TKN/COD values of 1.6–28 mg/g. Stable operation was observed in all cases, even when no ammoniacal nitrogen was added to the cell. Improved electrochemical performance (measured as power density, W/m2) was observed as nitrogen limitation was imposed on the cells. Even with no ammonium addition, continuous function of the cell was maintained, at levels consistent with operation at balanced nutrient supplementation. The work has implicated biological nitrogen fixation as a potential source of nitrogen within the MFC. Whilst this hypothesis has yet to be confirmed, the work highlights the opportunity for continuous operation of microbial fuel cells utilising wastewaters with extremely low nitrogen levels, present in pulp and paper, pharmaceutical and petrochemical industries. Further, the described increases in some of the electrochemical indices (e.g. power density) under application of nitrogen limitation may provide a new approach to increasing fuel cell performance. Finally, the lack of any need to add supplemental nitrogen to a MFC-based wastewater treatment technology holds potential for significant financial and environmental savings.

Zentrale Ergebnisse

• ▸Improved electrochemical performance (measured as power density, W/m2) was observed as nitrogen limitation was imposed on the cells.
• ▸Continuous function of the cell was maintained, even with no ammonium addition, at levels consistent with operation at balanced nutrient supplementation.
• ▸Biological nitrogen fixation was implicated as a potential source of nitrogen within the MFC.

Schlagwörter

Kennungen

DOI

10.2166/wst.2011.111

Zeitschrift

Water Science and Technology

Jahr

2011