title: Methane oxidation at a surface-sealed boreal landfill.
abstract: Methane oxidation was studied at a closed boreal landfill (area 3.9 ha, amount of deposited waste 200,000 tonnes) equipped with a passive gas collection and distribution system and a methane oxidative top soil cover integrated in a European Union landfill directive-compliant, multilayer final cover. Gas wells and distribution pipes with valves were installed to direct landfill gas through the water impermeable layer into the top soil cover. Mean methane emissions at the 25 measuring points at four measurement times (October 2005-June 2006) were 0.86-6.2 m(3) ha(-1) h(-1). Conservative estimates indicated that at least 25% of the methane flux entering the soil cover at the measuring points was oxidized in October and February, and at least 46% in June. At each measurement time, 1-3 points showed significantly higher methane fluxes into the soil cover (20-135 m(3) ha(-1) h(-1)) and methane emissions (6-135 m(3) ha(-1) h(-1)) compared to the other points (< 20 m(3) ha(-1) h(-1) and < 10 m(3) ha(-1) h(-1), respectively). These points of methane overload had a high impact on the mean methane oxidation at the measuring points, resulting in zero mean oxidation at one measurement time (November). However, it was found that by adjusting the valves in the gas distribution pipes the occurrence of methane overload can be to some extent moderated which may increase methane oxidation. Overall, the investigated landfill gas treatment concept may be a feasible option for reducing methane emissions at landfills where a water impermeable cover system is used.
authors.affiliation: Department of Biological and Environmental Sciences, University of Jyväskylä, Finland. juha.einola@bytl.jyu.fi
authors.forename: Juha
authors.initials: J
authors.lastname: Einola
authors.forename: Kai
authors.initials: K
authors.lastname: Sormunen
authors.forename: Anssi
authors.initials: A
authors.lastname: Lensu
authors.forename: Antti
authors.initials: A
authors.lastname: Leiskallio
authors.forename: Matti
authors.initials: M
authors.lastname: Ettala
authors.forename: Jukka
authors.initials: J
authors.lastname: Rintala
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis; D008697:Methane / Q000032:analysis / Q000737:chemistry*; D010084:Oxidation-Reduction; D012044:Regression Analysis; D018505:Waste Management / Q000379:methods*
chemical_list: D002245:Carbon Dioxide; D008697:Methane