Scaling-up of a novel, simplified MFC stack based on a self-stratifying urine column

Walter, X. A., Gajda, I., Forbes, S., Winfield, j., Greenman, J. and Ieropoulos, I. (2016) Scaling-up of a novel, simplified MFC stack based on a self-stratifying urine column. Biotechnology for Biofuels, 9 (93). ISSN 1754-6834 Available from:

PDF - Published Version
Available under License Creative Commons Attribution 4.0.


Publisher's URL:


Background The microbial fuel cell (MFC) is a technology in which microorganisms employ an electrode (anode) as a solid electron acceptor for anaerobic respiration. This results in direct transformation of chemical energy into electrical energy, which in turn transforms organic wastewater into fuel. Amongst the various types of organic waste, urine is interesting since it is the source of 75% of the nitrogen present in domestic wastewater despite only accounting for 1% of the total volume. However, there is a persistent problem for efficient MFC scale-up, since the higher the surface area of electrode to volume ratio, the higher the volumetric power density. Hence, to reach usable power levels, collectives of MFC units could be connected together to produce higher voltage and current outputs; this can be done by combinations of series/parallel connections implemented both horizontally and vertically as a stack. This plurality implies that the units have a simple design for the whole system to be cost-effective. The goal of this work was to address the built these multiple MFCs into stacks for treating human urine. Results We report a novel membrane-less stack design using ceramic plates, with fully submerged anodes and partially submerged cathodes in the same urine solution. The cathodes covered the top of each ceramic plate whilst the anodes, were on the lower half of each plate; this would constitute a module. The MFC elements in each module (anode, ceramic, cathode) were connected in parallel and different modules connected in series. This allowed self-stratification of the collective environment (urine column) under the natural activity of the microbial consortia thriving in the system. The module footprints were enlarged from 900 mL to 5000 mL and, importantly, this scaling-up increased power but did not negatively affect power density (≈ 12 W/m3), a factor that has proven an obstacle in previous studies. Conclusion The scaling-up approach, with limited power density losses, was achieved by maintaining a plurality of microenvironments within the collective and resulted in a simple, robust system fuelled by urine. This scaling-up approach, within the tested range, was successful in converting chemical energy in urine into electricity.

Item Type:Article
Uncontrolled Keywords:partially submerged cathodes, scaling-up, ammonium abstraction, microbial fuel cell stack, bioenergy
Faculty/Department:Faculty of Environment and Technology
ID Code:28549
Deposited By: Dr X. Walter
Deposited On:30 Mar 2016 13:25
Last Modified:03 May 2018 19:44

Request a change to this item

Total Document Downloads in Past 12 Months

Document Downloads

Total Document Downloads

More statistics for this item...