Landfill Gas Flow — Effects of Asymmetry

Abstract

Waste disposal is the responsibility of cities throughout the world. The most common method in North America is to bury waste in landfills. Landfill operators comply with regulations to control hazardous emissions known as landfill gas (LFG). The gas is extracted via horizontal or vertical wells and removed from the site. This study examines arrays of horizontal wells placed side by side or stacked, and resultant landfill gas flux between adjacent cells. A landfill's lifetime often sees changes in the number, relative location and efficacy of wells. The ability to predict the response of an array of wells to variation in a single well's fu nctionality is an essential aspect of landfill design and operation. The integrated normal flux between cells is identified as a salient quantity required to construct such prediction models. Numerical solution of flow equations reveals a stunningly simple dependence of the flux on the relative suction strength of proximate cells in a wide range of operational conditions. The flux is one of scarcely few parameters accessible in the field with relative ease and certainty, and thus traceable over time. This property makes the proposed models easy to construct, implement and adjust in practice in custom configurations.