Field Intercomparisons of Methods to Measure Fugitive Methane Emissions
Investigators: SCS Engineers
Presently, the greenhouse gas (GHG) emissions understanding and measurement is a global and imperative environmental concern. In light of this, biogas (and thus methane) emitted from landfills to the atmosphere is a prior topic for waste management, regarding the landfill environmental impact and the landfill gas recovery systems efficiency assessment. In fact, in developed country, landfills are estimated to contribute for around 2% of the global greenhouse gas emissions. In these countries, the total amount of 2% has been remaining stable for the past few years, due to compulsory gas collection implementation on landfills.
It appears that it is more and more important to be able to measure directly and accurately fugitive emissions, in order to improve landfills management and landfills performances monitoring. Researchers, regulators and landfill owners have all struggled to better define the actual emissions as compared to modelled emissions.
To measure these fugitive methane emissions directly on landfills, several methods exist and have already been used and evaluated, showing the heterogeneity and uncertainties of methods due to the emissions complexity.
Today, landfills GHG emissions have to be registered nationally (for instance, EPRTR registration in Europe). GHG amounts are calculated with the help of theoretical biogas production/collection models and do not rely on direct measurement. In fact, among the current available measurement techniques, none is in a position to be recognized as an international reference.
As international landfill operator companies, Veolia Environmental Services (VES) and Waste Management (WM) have the will to measure as precisely as possible the methane fugitive emissions from their landfills, using the most cost effective method. This was conducted under a technology exchange between the two companies. In 2008, recent developments in this research field has led the CRPE, the Waste Research Centre of Veolia Environment, in collaboration with Veolia Environmental Services North America (VESNA) and Waste Management (WM), with the financial support of Environmental Research and Education Foundation (EREF), to start a new intercomparison campaign, in order to assess the abilities of new techniques, mainly based on a spectroscopic analysis of the methane atmospheric dispersion.
The campaign took place from the 29th of September to the 11th of October 2008. For these two weeks, the companies tested emissions from the WM-owned Metro Recycling and Disposal Facility and from the Veolia-owned Emerald Park landfill, both in Franklin, Wisconsin.
In collaboration with the US Environmental Protection Agency (USEPA), a QA/QC (Quality Assurance/Quality Control plan) of category III (applied research) has been created.
This campaign aims at assessing the real field performances of the available measurement methods, and at depicting the most efficient and most representative use of each method in the given conditions (landfill characteristics, weather conditions, and time allowed), based on metrological, technical and economical criteria.
Parallel to the landfill fugitive emissions itself, the other important aspect of this study was to assess with a common reference the available methods for landfill fugitive emissions measurement.
Five methods for methane landfill emission measurement (VRPM, Tracer Gas, Flux chambers, DiAL, Eddy-Covariance) have been compared during a 2 week campaign in Franklin, Wisconsin. The study aimed at testing the methods both on a controlled methane release area and on real field conditions. A complete comparison regarding metrological, technical and economical performances is proposed, showing the limits and utiliztion conditions of the methods. Analysis of results is nearly complete and a final report is in preparation.