Landfill biocovers have been proven as a green and efficient technology to mitigate landfill methane emissions. Thermal, hydraulic, mechanical and bio-chemical (THMBC) factors regulate biocover behaviour. The aim of the current study is to evaluate the geotechnical and geo-environmental response or performance of compost based biocovers under freeze-thaw conditions. A comprehensive experimental program, including tests on samples as well as biocover column experiments, has been conducted. The results demonstrate that the thermal properties (thermal conductivity and thermal diffusivity) of the biocovers change due to the FTCs. Moreover, the outcomes of the column experiments demonstrate that biocover performance remains at an acceptable level even after experiencing two FTCs despite that most of the THMBC parameters in the biocover have changed due to the impacts of the FTCs and methane injection. The findings presented in this thesis will contribute to a better understanding and design of compost biocovers in cold regions.

Landfill biocovers have been proven as a green and efficient technology to mitigate landfill methane emissions. Thermal, hydraulic, mechanical and bio-chemical (THMBC) factors regulate biocover behaviour. The aim of the current study is to evaluate the geotechnical and geo-environmental response or performance of compost based biocovers under freeze-thaw conditions. A comprehensive experimental program, including tests on samples as well as biocover column experiments, has been conducted. The results demonstrate that the thermal properties (thermal conductivity and thermal diffusivity) of the biocovers change due to the FTCs. Moreover, the outcomes of the column experiments demonstrate that biocover performance remains at an acceptable level even after experiencing two FTCs despite that most of the THMBC parameters in the biocover have changed due to the impacts of the FTCs and methane injection. The findings presented in this thesis will contribute to a better understanding and design of compost biocovers in cold regions.

Countries around the world face social, economic, and ecological damage from escalating natural disasters caused by climate change. In an effort to curtail climate change impacts, local and regional governments are beginning to employ green house gas (GHG) mitigation strategies to reduce their carbon footprint. These strategies work to eliminate a range of GHG emissions from entering the atmosphere. Apart from carbon dioxide (CO₂), the most prevalent GHG is methane. In terms of global warming, methane is approximately 21 times more harmful to the atmosphere than CO₂. Natural gas systems, coal mining, manure management, rice cultivation, wastewater treatment, and landfills all contribute to methane generation. According to the US Environmental Protection Agency's 2011 US GHG inventory, landfills generate 1.5% of total GHG emissions in carbon dioxide equivalents. Recognizing the global impacts of its policies and operations, municipalities are working to reduce their GHG emissions. Coalitions like the C40 Cities Climate Leadership Group were created to specifically address GHG reductions, which will result in a 248 million MT reduction in GHGs released to the atmosphere by 2020. Guided by existing literature, this Master's Report calculates methane generation and transport to determine the effectiveness of applying two methane mitigation alternatives--passive methane oxidation biocovers (PMOBs) and landfill gas to energy technologies (LFGTE)--at an inactive landfill site to reduce GHG emissions. LFGTE generates energy for direct use such as space heating or industrial processes or for electricity generation. Cost-saving strategies abound for landfills which utilize LFGTE. PMOBs optimize the landfill surface soil cover environment to promote microbial growth of bacteria, called methanotrophs, which convert methane into carbon dioxide. When employed, these mitigation alternatives are designed to significantly reduce methane emissions from landfills. The EPA has developed a computer modeling program (LANDGEM) to aid in the calculation of landfill gas generation. A hypothetical case study of a one million ton landfill was created and modeled for methane generation over a 35 year period. With methane generation rates calculated, assessment of potential LFGTE was performed and methane oxidation rate calculations were made to determine the impact of a PMOB and LFGTE on net GHG emissions at the landfill. The overall GHG reductions with these engineering controls were two-thirds of the level a landfill without controls would emit. These results indicate that implementing methane mitigation steps at closed landfills throughout the world would yield significant reductions in GHG emissions. / text