-
[show abstract]
[hide abstract]
ABSTRACT: Effects of cathode types on the long-term stability of microbial fuel cell (MFC) and the anodic microbial communities were studied using K(3)Fe(CN)(6) catholyte (R1), air cathode (R2) and biocathode (R3) over a testing time of 400 d. Upon 400 d of testing, the maximum power densities (P(max)) of R1 and R2 decreased by 44% and 37%, and the Coulombic efficiencies (CEs) decreased 8.4% (R1) and 2.0% (R2), respectively, using the performances on 10d as the comparison basis. Conversely, the P(max) and CE of R3 increased by 68.2% and 116.8%, respectively. The non-ohmic resistances (R(no)) in all tests were the principal contributors of cell internal resistances. Phylogenetic analyses revealed that the microbial communities on anodic surface varied with cathode types and operational history.
Bioresource technology 05/2012; 118:249-56. · 4.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Microbial fuel cells (MFCs) represent a new biological method for generating electricity directly from biodegradable compounds. Efficiency of MFCs using manure as substrate is generally low. This study proposed a new design by incorporating biocathodes into a three-chamber MFC, which yielded maximum power densities much higher than those reported in literature. The new design placed cylindrical anode chamber for easy stirring and two symmetrical cathodic chambers with reduced anode-cathode distance. The biocathodes were applied to reduce charge transfer resistance. Additionally, biocathode microbial community was cultured to enrich favorable microorganisms. With external loading of 100 Ω, the power densities for new biocathode MFC using 2, 4, 6, 8 and 10% total solids diary manure reached 7.85±1.0 W m(-3), 7.84±1.20 W m(-3), 8.15±0.20 W m(-3), 7.60±0.97 W m(-3) and 5.63±0.97 W m(-3), respectively. The pH drop as a result of manure hydrolysis limited the power output. To provide detailed information of the microbial community in the biocathode MFC, the 454-pyrosequencing technique was adopted. The Firmicutes, γ-, β-, α- and δ-Proteobacteria, Bacteroidetes and Actinobacteria were the major groups on the anode, while γ-, β-, and α-Proteobacteria, Bacteroidetes and Actinobacteria were the predominant groups on the cathode.
Biosensors & bioelectronics 11/2011; 31(1):537-43. · 5.43 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Microbial fuel cells (MFCs) with abiotic cathodes require expensive catalyst (such as Pt) or catholyte (such as hexacynoferrate) to facilitate oxidation reactions. This study incorporated biocathodes into a three-chamber MFC to yield electricity from sewage sludge at maximum power output of 13.2 ± 1.7 W/m(3) during polarization, much higher than those previously reported. After 15 d operation, the total chemical oxygen demand (TCOD) removal and coulombic efficiency (CE) of cell reached 40.8 ± 9.0% and 19.4 ± 4.3%, respectively. The anolyte comprised principally acetate and propionate (minor) as metabolites. The use of biocathodes produced an internal resistance of 36-46 Ω, lower than those reported in literature works, hence yielding higher maximum power density from MFC. The massively parallel sequencing technology, 454 pyrosequencing technique, was adopted to probe microbial community on anode biofilm, with dominant phyla belonging to Proteobacteria (45% of total bacteria), Bacteroidetes (19%), Uncultured bacteria (9%), Actinobacteria (7%), Firmicutes (7%), Chloroflex (7%). At genera level, Rhodoferax, Ferruginibacter, Propionibacterium, Rhodopseudomonas, Ferribacterium, Clostridium, Chlorobaculum, Rhodobacter, Bradyrhizobium were the abundant taxa (relative abundances>2.0%).
Water Research 10/2011; 46(1):43-52. · 4.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this study, specialized bacteria were domesticated and cultivated with polluted stream water. The bioaugmentation of specialized bacteria would significantly enhance the removal efficiency of TN and NH4+-N from 25.9% to 50.3%, and from 34.5% to 60.1%, respectively. Concomitant increases in the number of microbial communities and the proportion of nitrifying bacteria were also identified by the most probable number (MPN) method. PCR-DGGE profiles revealed that the bacterial community could be successfully enriched and the ammonia-oxidizing bacteria communities were shown predominant by the species of Nitrosomonas. The biological contact oxidation ditch (BCOD) system augmented with specialized bacteria can be a viable alternative for treating polluted stream water to achieve improved nitrogen removal.
Bioresource technology 09/2010; 102(2):990-5. · 4.25 Impact Factor
