A field study to estimate the vertical gas diffusivity and permeability of compacted MSW using a barometric pumping analytical model

Abstract

The measurement of vertical gas diffusivity and permeability of compacted municipal solid waste (MSW) using an analytical gas flow and transport model was evaluated. A series of pressure transducers were buried in a MSW landfill and in situ pressures were modelled using an algorithm that predicts soil-gas pressures based on field-measured barometric pressure data and vertical diffusivity. The vertical gas diffusivity that represented the best-fit of the measured pressures was estimated at 20 locations and ranged from 0.002 to 0.052 m² s⁻¹. The vertical gas permeability ranged from 3.3 × 10⁻¹⁴ to 4.5 × 10⁻¹² m² for the upper-most 3 to 6 m of compacted MSW. The shortfalls of applying this method to landfill conditions are also discussed.