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Title: Effect of fed-batch vs. continuous mode of operation on microbial fuel cell performance treating biorefinery wastewater

Bioelectrochemical systems have been shown to treat low-value biorefinery streams while recovering energy, however, low current densities and anode conversion efficiencies (ACE) limit their application. A bioanode was developed via enrichment of electroactive biofilm under fed-batch and continuous feeding conditions using corn stover-derived waste stream. The continuously-fed MFC exhibited a current density of 5.8±0.06 A/m2 and an ACE of 39%±4. The fed-batch MFC achieved a similar current density and an ACE of 19.2%, however, its performance dropped after 36 days of operation to 1.1 A/m2 and 0.5%, respectively. In comparison, the ACE of the continuously-fed MFC remained stable achieving an ACE of 30% ± 3 after 48 days of operation. An MFC treating a biorefinery stream post fuel separation achieved a current density of 10.7±0.1 A/m2 and an ACE of 57% ± 9 at an organic loading of 12.5 g COD/L-day. Characterization of the microbial communities indicate higher abundance of Firmicutes and Proteobacteria and lower abundance of Bacteriodetes and a higher level of Geobacter spp. (1.4% vs. 0.2%) in continuously-fed MFC vs. fed-batch MFC. Finally, the results demonstrate that limiting substrate to the equivalent maximum current that the anode can generate, maintains MFC performance over a long term for highmore » strength wastewaters, such as those generated in the biorefinery.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3]
  1. Univ. of Tennessee, Knoxville, TN (United States)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
OSTI Identifier:
1263833
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Biochemical Engineering Journal
Additional Journal Information:
Journal Name: Biochemical Engineering Journal; Journal ID: ISSN 1369-703X
Publisher:
Elsevier
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); ORNL work for others; ORNL LDRD Director's R&D
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; 59 BASIC BIOLOGICAL SCIENCES bioelectrochemical systems; microbial fuel cells; biorefinery wastewater