LANDFILL GAS MIGRATION—FIELD INVESTIGATIONS AT SKELLINGSTED LANDFILL, DENMARK

The background for a landfill gas explosion accident which happened at Skellingsted Landfill in Denmark was investigated. To understand the behaviour of the lateral migrating landfill gas in the area where the accident occurred, an intensive in-vestigation was carried out after the explosion accident measuring time-series of gas composition in 30 wells over a 35-day period. The changes in gas composition in selected wells following a decrease in barometric pressure were measured over a 33-h period. The maximal distance for measured methane concentrations above 5% (vol.) in the pore gas was 90 m. The investigations showed that changes in barometric pressure have a great impact on the pore gas composition. Indications of methane oxidation were observed down to 2 m below ground in distances of more than 60 m from the landfill. Key Words—Landfill gas, migration, explosion accident, field investigation, baro-metric pressure, methane oxidation, Denmark