Microbial fuel cells for sulfide removal.
Thus far, microbial fuel cells (MFCs) have been used to convert carbon-based substrates to electricity. However, sulfur compounds are ubiquitously present in organic waste and wastewater. In this study, a MFC with a hexacyanoferrate cathodic electrolyte was used to convert dissolved sulfide to elemental sulfur. Two types of MFCs were used, a square type closed to the air and a tubular type in which the cathode compartment was open to the air. The square-type MFCs demonstrated a potential-dependent conversion of sulfide to sulfur. In the tubular system, up to 514 mg sulfide L(-1) net anodic compartment (NAC) day(-1) (241 mg L(-1) day(-1) total anodic compartment, TAC) was removed. The sulfide oxidation in the anodic compartment resulted in electricity generation with power outputs up to 101 mW L(-1) NAC (47 W m(-3) TAC). Microbial fuel cells were coupled to an anaerobic upflow anaerobic sludge blanket reactor, providing total removals of up to 98% and 46% of the sulfide and acetate, respectively. The MFCs were capable of simultaneously removing sulfate via sulfide. This demonstrates that digester effluents can be polished by a MFC for both residual carbon and sulfur compounds. The recovery of electrons from sulfides implies a recovery of energy otherwise lost in the methane digester.
Rabaey
Korneel
K
Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. Korneel.Rabaey@ugent.be
Van de Sompel
Kirsten
K
Maignien
Lois
L
Boon
Nico
N
Aelterman
Peter
P
Clauwaert
Peter
P
De Schamphelaire
Liesje
L
Pham
Hai The
HT
Vermeulen
Jan
J
Verhaege
Marc
M
Lens
Piet
P
Verstraete
Willy
W
D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D001674:Bioelectric Energy Sources; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D012722:Sewage; D013440:Sulfides / Q000302:isolation & purification*
D012722:Sewage; D013440:Sulfides