Quantification of methane emissions from danish landfills

Whole-landfill methane emission was quantified using a tracer technique that combines controlled tracer gas release from the landfill with time-resolved concentration measurements downwind of the landfill using a mobile high-resolution analytical instrument. Methane emissions from 13 Danish landfills varied between 2.6 and 60.8 kg CH₄ h^–1. The highest methane emission was measured at the largest (in terms of disposed waste amounts) of the 13 landfills, whereas the lowest methane emissions (2.6-6.1 kgCH₄ h^–1) were measured at the older and smaller landfills. At two of the sites, which had gas collection, emission measurements showed that the gas collection systems only collected between 30-50% of the methane produced (assuming that the produced methane equalled the sum of the emitted methane and the collected methane). Significant methane emissions were observed from disposed shredder waste. At Odense an emission of 19.7 kg CH₄ h^–1 was measured from a disposal cell containing 900,000 tons of shredder waste. Several of the sites had additional on-site waste treatment activities including composting and biological treatment, which resulted in significant methane emissions comparable to the emissions measured from waste disposal.