A coupled model for prediction of settlement and gas flow in MSW landfills

Abstract

SUMMARYPrediction of long-term settlement and control of gas pollution to the environment are two principle concerns during the management of municipal solid waste (MSW) landfills. The behavior of settlement and gas flow in MSW landfills is complicated due to the combined effect of mechanical deformation of the solid skeleton and continuous biodegradation of the waste. A one-dimensional settlement and gas flow model is presented in this paper, which is capable of predicting time evolution of settlement as well as temporal and spatial distribution of gas pressure within multi-layered landfills under a variety of operating scenarios. The analytical solution to the novel model is evaluated with numerical simulation and field measurements. The resulting efficiency and accuracy highlight the capability of the proposed model to reproduce the settlement behavior and gas flow in MSW landfills. The influences of operating conditions and waste properties on settlement and gas pressure are examined for typical MSW landfills.

A process-based inventory model for landfill CH4emissions inclusive of seasonal soil microclimate and CH4oxidation

“…Thus, CALMIM estimates annual CH 4 emissions while accounting for climate‐induced variability on transport and microbial oxidation. Although more complex models exist for predicting the flow of landfill gas as a function of diffusion and advection [ Findikakis and Leckie , 1979; Findikakis et al , 1988; Lang et al , 1989; Kindlein and Ahrens , 2006; Donovan et al , 2010; Yu et al , 2010], a number of the assumptions in these models are often violated in field settings (e.g., homogeneity of waste mass; uniform characteristics; static CH 4 generation rates). (Please consult the for a detailed discussion of diffusive versus advective processes in landfill cover soils.)…”

Gas flow to a vertical gas extraction well in deformable MSW landfills

“…c Based on intrinsic permeability of 10 −12 m 2 and gas viscosity of 1.37 × 10 −8 kPa s mentioned by Townsend et al [26]. rheological model and gas flow based on Darcy's law [27]. The landfill is treated as impermeable at the base and free venting at the top surface.…”

Numerical simulation of landfill gas pressure distribution in landfills

“…The calculation results of the model of Yu et al (2009) show that the migration of LFG at the bottom is vertical and horizontal, and there is only horizontal migration in this model. However, the form and the solving process of this model are simpler compared to the model of Yu et al (2009), so this model is more valuable in engineering. The relative pressure distribution form and range of this model are almost the same, and the error of the two results is in the permissible engineering error range.…”

“…Chen et al (2003) describe the migration of LFG in passive pumping wells using numerical models. Yu et al (2009) put forward an axisymmetric model which took the extraction well as central. Hashemi et al (2002) and Sanchez et al (2006) studied the effect of the capping of the landfill and the anisotropy of the landfill, in both a steady and a dynamical case, on LFG migration.…”

“…Because the production and the migration process of LFG is related to many disciplines and there are many influencing factors, the factors that are taken into account are different and there are many theoretical bases to be chosen when a model is established. In their models, Yu et al (2009) took into account the settlement of landfill, Hettiaratchi et al (2009) took into account leachate migration and settlement of landfill, and Gholamifarda et al (2008) took into account leachate and energy migration. Sanchez et al (2010) established a model to simulate the migration of LFG inside, where the leachate migration was taken into account.…”