Numerical Simulation of the Radius of Influence for Landfill Gas Wells

Abstract

The physical properties of waste (e.g., density, porosity, saturation, permeability) largely influence gas migration In North America, most domestic waste produced is disposed in rates. Several studies treat physical properties of waste landfills. These sites generate leachate and gas, mainly CH 4 and CO 2 , which are harmful for the environment if not properly controlled.under saturated flow conditions (Sowers, 1973; Findi-The design of active landfill gas recovery systems is based in large part kakis and Leckie, 1979; Schroeder et al., 1983 Schroeder et al., , 1994; Blais, on the radius of influence of vertical pumping wells. This parameter is 1996). There is a general agreement that these propercommonly estimated empirically. This study presents results of numerities are highly variable within each landfill site. Howcal simulations of the radius of influence of gas recovery wells for different ever, unsaturated hydraulic properties of waste are poorly site conditions. The simulations were performed with the TOUGH2known, mainly due to the difficulties related to theirLGM simulator. In the simulation scenarios, the radius of influence measurement under field or laboratory conditions. Bewas defined in relation to several factors: the waste thickness, the generacause of the absence of such data, it is necessary to relate tion rate of CH 4 gas in the waste, and CH 4 concentration in the recovered unsaturated waste properties to those of soils assumed landfill gas. The results are presented in the form of general graphs that are not site-specific. The adequacy of the results still needs to be to have similar properties. In his model, Nastev (1998) validated against field measurements. On the basis of simulation re-used the unsaturated properties of sandy-silt soil as analsults, a systematic approach is proposed for the design of landfill gas ogous to those of the waste and applied corresponding recovery systems, and this approach is illustrated with a hypothetic capillary parameters, an approach we adopt here. example. This approach should guide landfill managers and engineersLandfill characterization studies were followed by the in the design of landfill gas recovery systems. The simulations only development of suitable methods for controlling gas considered cases where landfills are open to the atmosphere, which migration and performing active gas recovery (EMCON are representative of most operating conditions. The results thus do

Study on optimizing evaluation and recovery efficiency for landfill gas energy collection

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Leachate Recirculation for Enhancing Methane Generation within Field Site in China

“…e horizontal well was placed 3 m below the cover. e influence radius of the vertical well is estimated to be 22 m [20]. e influence area of the horizontal well for liquid filling should be lower than that of the vertical well for gas pumping to increase the efficiency of methane collection within the site.…”

Evaluation of dual permeability of gas flow in municipal solid waste: Extraction well operation

“…Chen et al developed the 2D quasi-steady equation of gas flow and presented the gas pressure distribution in a passive vent operation [10]. Following the work of Nastev [7], Vigneault et al predicted the influence radius of a vertical well under the operation conditions of TOUGH2-LGM [11]. Additionally, the gas flow coupling mathematical model that considers settlement was proposed in the literature to address the long-term distribution of landfill gas [12,13].…”

“…Following the work of Nastev [7], Vigneault et al . predicted the influence radius of a vertical well under the operation conditions of TOUGH2‐LGM . Additionally, the gas flow coupling mathematical model that considers settlement was proposed in the literature to address the long‐term distribution of landfill gas .…”