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| Titel |
Methane Emissions from Landfill: Isotopic Evidence for Low Percentage of Oxidation from Gas Wells, Active and Closed Cells |
| VerfasserIn |
David Lowry, Rebecca Fisher, Giulia Zazzeri, Aalia Al-Shalaan, James France, Mathias Lanoisellé, Euan Nisbet |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250140272
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| Publikation (Nr.) |
 EGU/EGU2017-3636.pdf |
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| Zusammenfassung |
| Large landfill sites remain a significant source of methane emissions in developed and
developing countries, with a global estimated flux of 29 Tg / yr in the EDGAR 2008 database.
This is significantly lower than 20 years ago due to the introduction of gas extraction systems,
but active cells still emit significant amounts of methane before the gas is ready for
extraction. Historically the methane was either passively oxidized through topsoil layers or
flared. Oxidation is still the primary method of methane removal in many countries, and
covered, remediated cells across the world continue to emit small quantities of
methane.
The isotopic signatures of methane from landfill gas wells, and that emitted from active
and closed cells have been characterized for more than 20 UK landfills since 2011, with more
recent work in Kuwait and Hong Kong. Since 2013 the emission plumes have been identified
by a mobile measurement system (Zazzeri et al., 2015). Emissions in all 3 countries have a
characteristic δ13C signature of -58 ± 3 ‰ dominated by emissions from the active cells,
despite the hot, dry conditions of Kuwait and the hot, humid conditions of Hong Kong. Gas
well samples define a similar range. Surface emissions from closed cells and closed landfills
are mostly in the range -56 to -52 ‰Ṫhese are much more depleted values than those
observed in the 1990s (up to -35 ) when soil oxidation was the dominant mechanism of
methane removal.
Calculations using isotopic signatures of the amount of methane oxidised in these closed
areas before emission to atmosphere range from 5 to 15%, but average less than 10%, and are
too small to calculate from the high-emitting active cells. Compared to other major
methane sources, landfills have the most consistent isotopic signature globally, and are
distinct from the more 13C-enriched natural gas, combustion and biomass burning
sources.
Zazzeri, G. et al. (2015) Plume mapping and isotopic characterization of
anthropogenic methane sources, Atmospheric Environment, 110, 151-162,
doi.org/10.1016/j.atmosenv.2015.03.029. |
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