Modeling the oxygen transport process under preferential flow effect in landfill.

Evaluation of oxygen distribution during aeration in landfill is significantly important to determine the design parameters of an injection well. A coupling model describing gas preferential transport in a landfill was developed, which linked the effect of advection-diffusion and oxidation reaction and mass exchange between the fracture and the matrix system. The quantitative simulation of the variation in gas distribution during vertical well aeration in short term was presented, combined with the typical cases in field site. The parameter sensitivity in the coupling model to gas transport was addressed. Simulation result of the oxygen and methane concentrations by using the dual advective-diffusive (DAD) model, which considered the immobile zone effect, was closer to the monitoring data than that by using single advective-diffusive model. The variation of the AR under aeration was presented with the key parameters to provide the theory evidence for gas well design in landfill. This study provided reference for the design of the gas injection well distribution in aerobic landfill.