Biological denitrification in microbial fuel cells.
Microbial fuel cells (MFCs) that remove carbon as well as nitrogen compounds out of wastewater are of special interest for practice. We developed a MFC in which microorganisms in the cathode performed a complete denitrification by using electrons supplied by microorganisms oxidizing acetate in the anode. The MFC with a cation exchange membrane was designed as a tubular reactor with an internal cathode and was able to remove up to 0.146 kg NO(3-)-N m(-3) net cathodic compartment (NCC) d(-1) (0.080 kg NO(3-)-N m(-3) total cathodic compartment d(-1) (TCC)) at a current of 58 A m(-3) NCC (32 A m(-3) TCC) and a cell voltage of 0.075 V. The highest power output in the denitrification system was 8 W m(-3) NCC (4 W m(-3) TCC) with a cell voltage of 0.214 V and a current of 35 A m(-3) NCC. The denitrification rate and the power production was limited bythe cathodic microorganisms, which only denitrified significantly at a cathodic electrode potential below 0 V versus standard hydrogen electrode (SHE). This is, to our knowledge, the first study in which a MFC has both a biological anode and cathode performing simultaneous removal of an organic substrate, power production, and complete denitrification without relying on H2-formation or external added power.
Clauwaert
Peter
P
Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
Rabaey
Korneel
K
Aelterman
Peter
P
de Schamphelaire
Liesje
L
Pham
The Hai
TH
Boeckx
Pascal
P
Boon
Nico
N
Verstraete
Willy
W
D001674:Bioelectric Energy Sources; D004566:Electrodes; D006108:Graphite / Q000737:chemistry; D009566:Nitrates / Q000302:isolation & purification* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000378:metabolism
D009566:Nitrates; D014874:Water Pollutants, Chemical; D006108:Graphite