 |
| Titel |
Implications of CO2 Geological Storage on Aquifers Autotrophic Communities |
| VerfasserIn |
Sébastien Dupraz, Antonin Fabbri, Catherine Joulian, Bénédicte Ménez, Emmanuelle Gérard, Benoit Henry, Catherine Crouzet, François Guyot, Francis Garrido |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250044374
|
|
|
|
|
|
| Zusammenfassung |
| In a global strategy of carbon emission reduction, a study about CCS (Carbon Capture and
Storage) feasibility in the case of a French beet sugar factory and distillery in the Parisian
basin was undertaken by regional and state authorities. Besides, economical, geological and
engineering questions, microbial interactions were also studied since the potential
contribution of the deep biosphere on the storage zones appears to be an essential factor in
terms of injectivity and CO2 mobilization. Biological processes like biofilm formation,
biomineralization and carbon assimilation may hinder the injections or, to the contrary,
improve the stability of the sequestration by shifting CO2 into more stable forms like
carbonates and organic matter. Regarding those possibilities, it is thus mandatory to establish
how the subsurface biosphere will react by determining which metabolisms will be able to
sustain the stress due to high concentrations of CO2 and the resulting acidification. In that
case, the study of autotrophic communities reactivity is essential because they are the
only entrance for CO2 assimilation in the SLiMEs (Subsurface Litho autotrophic
Microbial Ecosystems) and thus are accountable for the general biomass and biofilm
production in the deep subsurface. Nevertheless, a simple assessment of the toxical effect
induced on these strains cannot be representative of the possible interactions at the
scale of a long term storage where adaptations should play a major role. For that
reason, we decided to choose different strains, namely autotrophic methanogens
(Methanothermococcus thermolithotrophicus and Archeoglobus fulgidus) and sulfate
reducing bacteria strains (Desulfotomaculum geothermicum and Desulfotomaculum
kuznetsovii), that best characterize the autotrophic communities of our injection site
(aquifer of the Triassic Keuper sandstones) and to make them undergo a test of
selection/adaptation toward a sequential increase of CO2 partial pressure from 0.05 to 5 bar.
Artificial ground water was formulated in order to mimic the local compositions and
implemented in accordance with the organic matter (50 ppm) that does correspond to
the residues of volatil organic carbon present in the injected gas and originating
from the beet fermentative processes. Strains were tested separately and together in
order to assess competitive and symbiotic effects, chemistry and microbial activities
were measured at each step. At the end of this process, the combinations that have
succeeded to reach the highest levels of CO2 were inoculated into a bioreactor
and submitted to a test of CO2 injection in conditions that are similar to what is
expected in practice (pressures superior to 100 bar). General results conclude on the
importance of microbial influence in such systems, especially in regards of their
adaptation.
. |
|
|
|
|
|
|