Gas Migration in Layered Landfills Incorporating Vertical and Horizontal Extraction Wells

Abstract:

A new two dimensional gas flow model was developed to analyze the gas migration in layered landfills. The model considers anisotropy of the municipal solid wastes(MSWs), and vertical variations in both gas generation and permeability caused by compression, degradation and inhomogeneous distribution of moisture content. The general solution of this model can be developed using eigenfunction expansion method, and the unknown integration constants can be determined by the boundary and continuity conditions. According to this analytical solution, the influences of vertical wells, horizontal lines and permeable layers on the gas pressure and recovery were further investigated. Finally, the design method of the landfill gas (LFG) collection system for layered landfills covered by geomembrane was proposed.

Key words:layered landfill; vertical well; horizontal line; permeable layer; geomembrane