Influence of High-Permeability Layers for Enhancing Landfill Gas Capture and Reducing Fugitive Methane Emissions from Landfills |
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Authors: | Yoojin Jung Paul T Imhoff Don C Augenstein Ramin Yazdani |
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Affiliation: | 1Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Delaware, Newark, DE 19716. E-mail: yjjung@udel.edu 2Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Delaware, Newark, DE 19716. E-mail: imhoff@udel.edu 3Technical Director, Institute of Environmental Management, Inc.dient, 4277 Pomona Ave., Palo Alto, CA 94306. E-mail: iemdon@aol.com 4Senior Civil Engineer, Yolo County Planning and Public Works Dept., Division of Integrated Waste Management, Yolo County, 44090 County Rd. 28H, Woodland, CA 95776. E-mail: ramin.yazdani@yolocounty.org
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Abstract: | Gas collection systems of various designs have been used to control landfill gas emissions, which can be problematic, particularly before installation of final landfill covers. In this work, an innovative gas collection system that includes a permeable layer near the top surface of landfills was evaluated for enhancing capture of landfill gas and reducing fugitive methane emissions. A computational model that accounts for advective and diffusive fluxes of multiple gas components was used to evaluate the efficiency of this new design for intermediate landfill covers. The utility of the high-permeability gas-conductive layer was illustrated for several conditions of interest including varying refuse permeability, varying degrees of permeability anisotropy, and temporal atmospheric pressure changes. Simulations showed that the permeable layer decreased methane emissions by 43% when the horizontal to vertical permeability ratio for refuse was kh/kv = 3 and the domain average kh = 3×10?12?m2, while reductions in methane emissions decreased to 17% for the same anisotropy but with kh = 10?11?m2. With this design, barometric pressure changes did not significantly affect oxygen intrusion or methane emission rates. |
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Keywords: | Landfills Methane Municipal waste Permeability Diffusion Porous media Gas |
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