Landfill gas (LFG) is generated from the physical, chemical and biological processes that occur in disposed waste. The main components of LFG are methane (50-60%), carbon dioxide (40-50%) and some trace gases. Considering the fact that methane is a major greenhouse gas (GHG), collection of LFG will decrease fugitive GHG emissions, thus decreasing the environmental impacts which is the main goal of Florida’s “Serve to Preserve Summit and Energy Action Team Program.”
Considering the large population of Florida (ranked fourth in the US) and the fact that, at least for some decades, landfilling solid waste will be an inevitable part of waste management, regulators and owners/operators must focus on how to reduce environmental impacts and improve economic benefits of landfills. One solution is LFG to Energy (LFGTE) projects. By creating a LFGTE project, landfill owners and operators eliminate pollution by both reducing GHG emissions and providing a renewable source of energy.
In addition to environmental benefits, LFG reduction can yield economic benefits due to the market usages of methane. The methane can be used directly to produce energy via industrial heat plants or electrical power plants. These renewable energy projects have been operating for some time in the US, but with all the energy concerns the need for alter energy sources can only increase. As Florida is one of the leading states regarding environmental issues, these projects are gaining attention in Florida recently. The main focus of this project is to increase our knowledge on LFGTE projects and facilitating future projects in Florida.
LFGTE projects have been operating for years in a few Florida landfills, however, Florida is believed to have a much higher potential. The ultimate goal of this research is to improve the viability of LFGTE projects through case study analysis. Existing Florida LFGTE projects will be analyzed from the perspective of climate change. The role these landfills play with respect to current and future carbon emissions will be evaluated through LFG generation modeling, carbon footprint analysis, and economic analysis. Conclusions from these case studies will be extrapolated to all Florida landfills.
To date, data have been collected from five Florida landfills operating LFGTE projects. These data include location and topography, disposed waste tonnage, operation methods applied, history of waste disposal, waste characteristics, climatic conditions, actual collected LFG, and LFG sales contracts.
LFG generation model parameters based on the first-order model, i.e. the gas generation potential and gas generation decay rate, will be derived and the potential LFG generation will be calculated for these five landfills. Also the LFG collection efficiency will be calculated by comparing model outcomes to actual collection values, allowing an estimate of the carbon footprint of these landfills. The results will be extrapolated to other candidate Florida landfills. Furthermore, a sensitivity analysis will be done to study the effect of changes in characteristics such as waste composition and operational conditions, such as moisture content, timing of landfill capping, or biosolids addition, by evaluating the effect of changes on generation model parameters and LFG collection and use.