Single-chamber microbial fuel cells as on-line shock-sensors for volatile fatty acids in anaerobic digesters

During the last decade, bioprospecting for electrochemically active bacteria has included the search for new sources of inoculum for microbial fuel cells (MFCs). However, concerning power and current production, a Geobacter-dominated mixed microbial community derived from a wastewater inoculum remains the standard. On the other hand, cathode performance is still one of the main limitations for MFCs, and the enrichment of a beneficial cathodic biofilm emerges as an alternative to increase its performance. Glucose-fed air-cathode reactors inoculated with a rumen-fluid enrichment and wastewater showed higher power densities and soluble chemical oxygen demand (sCOD) removal (Pmax = 824.5 mWm−2; ΔsCOD = 96.1%) than reactors inoculated only with wastewater (Pmax = 634.1 mWm−2; ΔsCOD = 91.7%). Identical anode but different cathode potentials suggest that differences in performance were due to the cathode. Pyrosequencing analysis showed no significant differences between the anodic community structures derived from both inocula but increased relative abundances of Azoarcus and Victivallis species in the cathodic rumen enrichment. Results suggest that this rarely used inoculum for single-chamber MFCs contributed to cathodic biofilm improvements with no anodic biofilm effects.

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A comparative study on treatment of wastewaters with various biodegradability and various pH values using single-chamber microbial fuel cells

Water and Environment Journal ◽

10.1111/wej.12413 ◽

2018 ◽

Vol 33 (3) ◽

pp. 409-417

Author(s):

Safwat M. Safwat ◽

Ehab Rozaik ◽

Hisham Abdel-Halim

Keyword(s):

Fuel Cells ◽

Comparative Study ◽

Microbial Fuel Cells ◽

Single Chamber ◽

Ph Values

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Simultaneous nitrification, denitrification and electricity recovery of Halomonas strains in single chamber microbial fuel cells for seawater sewage treatment

Journal of Environmental Chemical Engineering ◽

10.1016/j.jece.2021.106761 ◽

2021 ◽

pp. 106761

Author(s):

Weifeng Liu ◽

Yaoting Wu

Keyword(s):

Fuel Cells ◽

Microbial Fuel Cells ◽

Sewage Treatment ◽

Single Chamber

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Application of Methanobrevibacter acididurans in anaerobic digestion

Water Science & Technology ◽

10.2166/wst.2004.0366 ◽

2004 ◽

Vol 50 (6) ◽

pp. 109-114 ◽

Cited By ~ 9

Author(s):

D.V. Savant ◽

D.R. Ranade

Keyword(s):

Fatty Acids ◽

Anaerobic Digestion ◽

Methane Production ◽

Volatile Fatty Acids ◽

Low Ph ◽

Anaerobic Digesters ◽

Hydrogenotrophic Methanogen ◽

Distillery Wastewater ◽

Acid Tolerant ◽

Acidic Conditions

To operate anaerobic digesters successfully under acidic conditions, hydrogen utilizing methanogens which can grow efficiently at low pH and tolerate high volatile fatty acids (VFA) are desirable. An acid tolerant hydrogenotrophic methanogen viz. Methanobrevibacter acididurans isolated from slurry of an anaerobic digester running on alcohol distillery wastewater has been described earlier by this lab. This organism could grow optimally at pH 6.0. In the experiments reported herein, M. acididurans showed better methanogenesis under acidic conditions with high VFA, particularly acetate, than Methanobacterium bryantii, a common hydrogenotrophic inhabitant of anaerobic digesters. Addition of M. acididurans culture to digesting slurry of acidogenic as well as methanogenic digesters running on distillery wastewater showed increase in methane production and decrease in accumulation of volatile fatty acids. The results proved the feasibility of application of M. acididurans in anaerobic digesters.

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Microbial Structure and Energy Generation in Microbial Fuel Cells Powered with Waste Anaerobic Digestate

Energies ◽

10.3390/en13184712 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4712

Author(s):

Dawid Nosek ◽

Agnieszka Cydzik-Kwiatkowska

Keyword(s):

Fuel Cells ◽

Microbial Fuel Cells ◽

Volatile Fatty Acids ◽

Current Knowledge ◽

Oxygen Demand ◽

Electricity Production ◽

Stable Operation ◽

Microbial Structure ◽

Microbial Composition ◽

Start Up

Development of economical and environment-friendly Microbial Fuel Cells (MFCs) technology should be associated with waste management. However, current knowledge regarding microbiological bases of electricity production from complex waste substrates is insufficient. In the following study, microbial composition and electricity generation were investigated in MFCs powered with waste volatile fatty acids (VFAs) from anaerobic digestion of primary sludge. Two anode sizes were tested, resulting in organic loading rates (OLRs) of 69.12 and 36.21 mg chemical oxygen demand (COD)/(g MLSS∙d) in MFC1 and MFC2, respectively. Time of MFC operation affected the microbial structure and the use of waste VFAs promoted microbial diversity. High abundance of Deftia sp. and Methanobacterium sp. characterized start-up period in MFCs. During stable operation, higher OLR in MFC1 favored growth of exoelectrogens from Rhodopseudomonas sp. (13.2%) resulting in a higher and more stable electricity production in comparison with MFC2. At a lower OLR in MFC2, the percentage of exoelectrogens in biomass decreased, while the abundance of genera Leucobacter, Frigoribacterium and Phenylobacterium increased. In turn, this efficiently decomposed complex organic substances, favoring high and stable COD removal (over 85%). Independent of the anode size, Clostridium sp. and exoelectrogens belonging to genera Desulfobulbus and Acinetobacter were abundant in MFCs powered with waste VFAs.

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