Quantification of multiple methane emission sources at landfills using a double tracer technique

A double tracer technique was used successfully to quantify whole-site methane (CH4) emissions from Fakse Landfill. Emissions from different sections of the landfill were quantified by using two different tracers. A scaled-down version of the tracer technique measuring close-by to localized sources having limited areal extent was also used to quantify emissions from on-site sources at the landfill facility, including a composting area and a sewage sludge storage pit. Three field campaigns were performed. At all three field campaigns an overall leak search showed that the CH4 emissions from the old landfill section were localized to the leachate collection wells and slope areas. The average CH4 emissions from the old landfill section were quantified to be 32.6 ± 7.4 kg CH4 h−1, whereas the source at the new section was quantified to be 10.3 ± 5.3 kg CH4 h−1. The CH4 emission from the compost area was 0.5 ± 0.25 kg CH4 h−1, whereas the carbon dioxide (CO2) and nitrous oxide (N2O) flux was quantified to be in the order of 332 ± 166 kg CO2 h−1 and 0.06 ± 0.03 kg N2O h−1, respectively. The sludge pit located west of the compost material was quantified to have an emission of 2.4 ± 0.63 kg h−1 CH4, and 0.03 ± 0.01 kg h−1 N2O.

Research highlights
► Precise and reliable measurements of emissions from landfills are needed.
► A tracer technique involving simultaneous release of two tracers was proven successful.
► Measurements to be performed at times with low changing trends in barometric pressure.