Correlation between Methane concentration and emission from old Landfills in Sweden

Abstract: There are several thousands of old landfills in Sweden and they are often located close to cities on valuable land, three of these landfills are Lassabacka in Varberg, Härlövsängar in Kristianstad and Onsjöparken in Eslöv. On these landfill methane- emission and concentration measurements are done with an IR Chamber called ULTRAMAT 23, a probe and the gas analyser LFG 20. This was done to see if there is any correlation between the emission and concentration of methane and to quantify the emission. This is done to see if easier concentration measurements are possible to do to get a realistic estimation of the emission and to get an overview of the paste and future emission and settlement. Theoretical productions on these sites will also be calculated with the US EPA Gas Emission Model to compare it with the measured results. There is a big difference between theoretical methane emission and measured methane emission at all three landfills. Thus, based on the results the theoretical emission is not a good estimation for the actual emission. From the theoretical results there have been years where it would have been profitable to extract gas for energy production at all the landfills, but today none of the landfills are of any value when looking at energy production. From the measurements a correlation between emission of methane and the methane concentration in the soil gas could be seen, from that an exposure limit and a lower explosion limit can be set to 0,27 g/m2/h. Based on the relationship it is also possible to use only the measurements with the probe and concentration measurement to evaluate if there is any methane emission from a landfill.