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- Title
- Characterization of Florida Landfills with Elevated Temperatures.
- Creator
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Joslyn, Ryan, Reinhart, Debra, Lee, Woo Hyoung, Randall, Andrew, University of Central Florida
- Abstract / Description
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The occurrence of elevated temperatures within landfills is a very challenging issue for landfill operators to detect and correct. Little is known regarding the causes of elevated temperatures (ETs) and the number of landfills currently operating under such conditions. Therefore, the goal of this research was to determine which landfills within Florida have been impacted by ETs, and to develop a more complete understanding of the factors that may lead to these landfills becoming elevated...
Show moreThe occurrence of elevated temperatures within landfills is a very challenging issue for landfill operators to detect and correct. Little is known regarding the causes of elevated temperatures (ETs) and the number of landfills currently operating under such conditions. Therefore, the goal of this research was to determine which landfills within Florida have been impacted by ETs, and to develop a more complete understanding of the factors that may lead to these landfills becoming elevated temperature landfills (ETLFs). Historical landfill gas wellhead data, waste deposition reports, and landfill site geometry were collected for 27 landfill cells through the FDEP OCULUS database and from landfill operators and owners. These data were evaluated to quantify the statistical characteristics that result in landfills becoming 'elevated' in temperature. Gas data included landfill gas temperatures, methane content, carbon dioxide content, and balance gas readings. Waste deposition information was gathered through solid waste reports for each landfill. Landfill site geometry was found through landfill permits, topographical landfill diagrams, and annual operation reports. Furthermore, landfill maps were created in ArcGIS to observe spatial distribution of ETs in landfills over time.Upon analysis of the landfill gas wellhead data, it was discovered that 74% of studied landfill cells had ET readings; regulatory limits specify a maximum allowable gas temperature of 55 degrees C (131 degrees F). When studying the solid waste reports, it was discovered that 37% of landfill cells contained MSW ash; of these cells, 90% of them are considered ETLFs. Regarding site geometry, it was found that ETLF cells are on-average double the site area and approximately 20 feet deeper than the average non-ETLF cell. Furthermore, results suggest that heat propagation in most landfills is limited; however, heat propagation is possible if gas wells are turned off for an extensive time period.
Show less - Date Issued
- 2019
- Identifier
- CFE0007471, ucf:52690
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007471
- Title
- LANDFILL GAS TO ENERGY: INCENTIVES & BENEFITS.
- Creator
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Amini, Hamid, Reinhart, Debra, University of Central Florida
- Abstract / Description
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Municipal solid waste (MSW) management strategies typically include a combination of three approaches, recycling, combustion, and landfill disposal. In the US approximately 54% of the generated MSW was landfilled in 2008, mainly because of its simplicity and cost-effectiveness. However, landfills remain a major concern due to potential landfill gas (LFG) emissions, generated from the chemical and biological processes occurring in the disposed waste. The main components of LFG are methane (50...
Show moreMunicipal solid waste (MSW) management strategies typically include a combination of three approaches, recycling, combustion, and landfill disposal. In the US approximately 54% of the generated MSW was landfilled in 2008, mainly because of its simplicity and cost-effectiveness. However, landfills remain a major concern due to potential landfill gas (LFG) emissions, generated from the chemical and biological processes occurring in the disposed waste. The main components of LFG are methane (50-60%) and carbon dioxide (40-50%). Although LFG poses a threat to the environment, if managed properly it is a valuable energy resource due to the methane content. Currently there are over 550 active LFG to energy (LFGTE) facilities in the US, producing renewable energy from LFG. A major challenge in designing/operating a LFGTE facility is the uncertainty in LFG generation rate predictions. LFG generation rates are currently estimated using models that are dependent upon the waste disposal history, moisture content, cover type, and gas collection system, which are associated with significant uncertainties. The objectives of this research were to: (1) Evaluate various approaches of estimating LFG generation and to quantify the uncertainty of the model outcomes based on case-study analysis, (2) Present a methodology to predict long-term LFGTE potential under various operating practices on a regional scale, and (3) Investigate costs and benefits of emitting vs. collecting LFG emissions with regards to operation strategies and regulations. The first-order empirical model appeared to be insensitive to the approach taken in quantifying the model parameters, suggesting that the model may be inadequate to accurately describe LFG generation and collection. The uncertainty values for the model were, in general, at their lowest within five years after waste placement ended. Because of the exponential nature, the uncertainty increased as LFG generation declined to low values decades after the end of waste placement. A methodology was presented to estimate LFGTE potential on a regional scale over a 25-year timeframe with consideration of modeling uncertainties. The methodology was demonstrated for the US state of Florida, and showed that Florida could increase the annual LFGTE production by more than threefold by 2035 through installation of LFGTE facilities at all landfills. Results showed that diverting food waste could significantly reduce fugitive LFG emissions, while having minimal effect on the LFGTE potential. Estimates showed that with enhanced landfill operation and energy production practices, LFGTE power density could be comparable to technologies such as wind, tidal, and geothermal. More aggressive operations must be considered to avoid fugitive LFG emissions, which could significantly affect the economic viability of landfills. With little economic motivation for US landfill owners to voluntarily reduce fugitive emissions, regulations are necessary to increase the cost of emitting GHGs. In light of the recent economic recession, it is not likely that a carbon tax will be established; while a carbon trading program will enforce emission caps and provide a tool to offset some costs and improve emission-reduction systems. Immediate action establishing a US carbon trading market with carbon credit pricing and trading supervised by the federal government may be the solution. Costs of achieving high lifetime LFG collection efficiencies are unlikely to be covered with revenues from tipping fee, electricity sales, tax credits, or carbon credit trading. Under scenarios of highly regulated LFG emissions, sustainable landfilling will require research, development, and application of technologies to reduce the marginal abatement cost, including: (1) Diverting rapidly decomposable waste to alternative treatment methods, (2) Reducing fugitive emissions through usage daily/intermediate covers with high oxidation potential, (3) Increasing the lifetime LFG collection efficiency, and (4) Increasing LFG energy value - for instance by producing high-methane gas through biologically altering the LFG generation pathway.
Show less - Date Issued
- 2011
- Identifier
- CFE0003960, ucf:48682
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003960
- Title
- DETERMINING FLORIDA LANDFILL ODOR BUFFER DISTANCES USING AERMOD.
- Creator
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Figueroa, Veronica, Cooper, C. David, University of Central Florida
- Abstract / Description
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As U.S. landfills continue to grow in size, concerns about odorous gas emissions from landfills are increasing. For states that are expanding in population, such as Florida, odors from landfills are a major concern because new housing developments, needed to accommodate the rapid population growth, are creeping closer and closer to the existing landfills. As homes get closer to landfills, odor complaints are likely to become more frequent, causing landfill managers increased problems with...
Show moreAs U.S. landfills continue to grow in size, concerns about odorous gas emissions from landfills are increasing. For states that are expanding in population, such as Florida, odors from landfills are a major concern because new housing developments, needed to accommodate the rapid population growth, are creeping closer and closer to the existing landfills. As homes get closer to landfills, odor complaints are likely to become more frequent, causing landfill managers increased problems with public interactions. Odor buffer zones around landfills need to be established to give municipalities tools to help prevent the building of future homes too close to landfills. Using the latest air dispersion model, AERMOD, research predicted downwind odor concentrations from a Central Florida landfill. Accurate estimates of methane emissions throughout a Central Florida landfill were determined using a new technique developed as part of this research that uses hundreds of ambient air VOC measurements taken within a landfill, as receptors. Hundreds of point sources were placed on the landfill, and the standard Gaussian dispersion equations were solved by matrix inversion methods. The methane emission rates were then used as surrogates for odor emissions to predict downwind odor concentrations via AERMOD. By determining a critical zone around a landfill with regards to odor, stakeholders will be able to meet regulatory issues and assist their communities. Other beneficial uses from this research include: determination of existing gas collection system efficiencies, calculation of fugitive greenhouse gas emissions from municipal solid waste (MSW) landfills, and improved landfill gas management.
Show less - Date Issued
- 2008
- Identifier
- CFE0002200, ucf:47910
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002200