Description
Landfill gas, consisting of methane, carbon dioxide and numerous trace organic compounds, is a natural product of the anaerobic decomposition of waste in landfills. While the production of landfill gas (LFG) is well documented, our ability to predict LFG production, collection, fugitive emissions, and attenuation in landfill covers, in consideration of the myriad of factors that control these processes, is imperfect. As a result, landfill owners have difficulty in (1) accurately predicting LFG production rates and their variation with landfill operation (e.g., dry tomb vs. bioreactor), and (2) accounting for the fraction of the generated gas that is collected. As a result of the uncertainty in LFG production and management, our ability to authoritatively calculate the overall carbon footprint of a landfill is imprecise. In addition, owners often have difficulty in eliminating sources of odors that result from waste decomposition and the presence of non- methane organic compounds (NMOCs) and hazardous air pollutants (HAPs).
In previous EREF-funded research, Camobreco et al. (1999) completed a life-cycle assessment (LCA) of all aspects of a landfill including construction, operation, closure, post-closure maintenance, and leachate and gas management. This study, which was based on actual data provided by landfill owners across the U.S. and France, showed that LFG management, including collection, treatment, and energy recovery where practiced, was the dominant aspect of a landfill in defining its overall environmental performance. Emissions associated with the gas are significantly higher than emissions associated with construction, operations, closure and post-closure.
Landfills frequently attract attention in discussions of the impact of waste management on climate change. This is because they are estimated to be the third largest source of anthropogenic methane emissions in the U.S. and the second largest source globally (4, 5). While there is uncertainty in emissions estimates, it is well established that landfills represent a source of greenhouse gas emissions, a source of “green” energy and a sink for biogenic carbon that is put into long-term storage in a landfill.
In 2007, the Environmental Research and Education Foundation identified the need to quantify the carbon footprint of a landfill as a research priority. Research to improve the ability to quantify the carbon footprint of a landfill will require millions of dollars, teams of researchers with expertise in several different aspects of landfills, and significant time. It is not likely that any one research group will be in a position, either financially and technically, to address each issue in a single project. Rather, progress will be incremental and a function of available funds and funding partners. EREF is the logical group to lead this mission-oriented research through financial support, availability of landfill sites for field work, and coordination of collaborative agreements with government agencies. Recognizing this, the EREF Research Council requested the development of an overall roadmap for specific research needs, and how they fit together to achieve the overall objective of improved predictability of the environmental performance of a landfill.
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