Autotrophic nitrite removal in the cathode of microbial fuel cells.
Nitrification to nitrite (nitritation process) followed by reduction to dinitrogen gas decreases the energy demand and the carbon requirements of the overall process of nitrogen removal. This work studies autotrophic nitrite removal in the cathode of microbial fuel cells (MFCs). Special attention was paid to determining whether nitrite is used as the electron acceptor by exoelectrogenic bacteria (biologic reaction) or by graphite electrodes (abiotic reaction). The results demonstrated that, after a nitrate pulse at the cathode, nitrite was initially accumulated; subsequently, nitrite was removed. Nitrite and nitrate can be used interchangeably as an electron acceptor by exoelectrogenic bacteria for nitrogen reduction from wastewater while producing bioelectricity. However, if oxygen is present in the cathode chamber, nitrite is oxidised via biological or electrochemical processes. The identification of a dominant bacterial member similar to Oligotropha carboxidovorans confirms that autotrophic denitrification is the main metabolism mechanism in the cathode of an MFC.
Laboratory of Chemical and Environmental Engineering (LEQUiA), Institute of the Environment, University of Girona, Campus Montilivi s/n, Facultat de Ciències, E-17071 Girona, Spain. sebastia@lequia.udg.cat
Sebastià
S
Puig
Marc
M
Serra
Ariadna
A
Vilar-Sanz
Marina
M
Cabré
Lluís
L
Bañeras
Jesús
J
Colprim
M Dolors
MD
Balaguer
D052818:Autotrophic Processes; D055162:Biocatalysis; D001673:Biodegradation, Environmental; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D018441:Biofilms; D058440:Denitrification; D055664:Electrochemical Techniques; D004566:Electrodes; D004583:Electrons; D009566:Nitrates / Q000032:analysis; D009573:Nitrites / Q000302:isolation & purification*; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid
D009566:Nitrates; D009573:Nitrites; D009584:Nitrogen