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| Titel |
Microbial fuel cell as mitigation strategy for methane emissions from paddy field |
| VerfasserIn |
Anacleto Rizzo, Fulvio Boano, Roberto Revelli, Luca Ridolfi |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250073816
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| Zusammenfassung |
| Microbial fuel cells (MFCs) are bioelectrochemical systems able to generate electricity from
wetland soils, including paddies, exploiting the microbial decomposition of organic matter. A
MFC is composed of an anode buried in the anaerobic submerged soil linked to a cathode
placed on the top of the soil in the aerobic ponding water. A biofilm develops on the anode,
where bacteria release electrons, oxidizing dissolved organic carbon (DOC) and
using oxygen available at the cathode as electron acceptor. MFC technology is now
in an early development stage and the efficiency in electricity production is still
low. However, MFC can also be applied for secondary aims, among which one
of great interest is the reduction of methane (CH4) emissions from paddy fields.
Indeed, DOC oxidation at the anode can be seen as an additional DOC sink in paddy
soil environment, limiting the DOC availability for methanogens. In this work, a
process-based mathematical model is proposed for a preliminary investigation of
the efficiency of MFCs in limiting CH4 emissions. The model relies on a system
of partial differential mass balance equations to describe the vertical dynamics
of the chemical compounds leading to CH4 production. Many physico-chemical
processes and features characteristic of paddy soil are included: paddy soil stratigraphy;
spatio-temporal variations of plant-root compartment; water and heat transport; SOC
decomposition; heterotrophic reactions in both aerobic and anaerobic conditions; root radial
oxygen loss; root solute uptake; DOC root exudation; plant-mediated, ebullition, and
diffusion gas exchange pathways. MFC is modeled as a DOC sink term, following a
zero-order kinetic where the current density is assumed constant for the whole growing
season. Different values of current density are tested, in accordance with values
reported in literature about efficiency reached in paddy soils. Our results show a
reduction of CH4 emissions up to -28.1%, -24.1%, and -26.5% of daily minimum,
daily maximum and total over the whole growing season, respectively, confirming
the potential validity of MFC as a novel CH4 mitigation strategy. Moreover, it is
shown that transport processes limit the mitigation of CH4 emissions at high current
density. Finally, in order to maximize the reduction of CH4 emissions, simulation
results suggest to place the anode in the middle portion of the superficial layer. |
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