Solute transport through preferential pathways in municipal solid waste

Rosqvist, Håkan; Destouni, Georgia

doi:10.1016/s0169-7722(00)00127-3

Cited by 74 publications

(65 citation statements)

References 26 publications

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“…This apparently indicates a highly preferential flow system. This is consistent with the mobile porosities reported by Fellner et al (2009) and Rosqvist & Destouni (2000). The block diffusion times (t cb s) are plotted against the compressive stress in Figure 5.…”

Section: Simulation Of Bromide Breakthroughsupporting

confidence: 87%

“…Conceivably, sub-parallel alignment of compressed plastic layers provides an approximately average block-like structure to the waste in the test-cells. There have been several studies which have found that diffusion to and from less mobile parts of the waste is an important transport mechanism (Bendz and Singh, 1999;Döberl et al, 2003;Rosqvist and Destouni, 2000;Woodman, 2007). These studies are supported by a broad evidence base as to the existence (albeit not the precise nature) of preferential flow (Bengtsson et al, 1994;Blakey, 1982;Ehrig, 1983;Fellner et al, 2009;Stegmann and Ehrig, 1989;Straub and Lynch, 1982).…”

Section: Simulationmentioning

confidence: 99%

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Investigating the effect of compression on solute transport through degrading municipal solid waste

et al. 2014

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The effect of applied compression on the nature of liquid flow and hence the movement of contaminants within Municipal Solid Waste was examined by means of thirteen tracer tests conducted on five separate waste samples. The conservative nature of bromide, lithium and deuterium tracers was evaluated and linked to the presence of degradation in the sample. Lithium and deuterium tracers were non-conservative in the presence of degradation, whereas the bromide remained effectively conservative under all conditions. Solute diffusion times into and out of less mobile blocks of waste were compared for each test under the assumption of dominantly dual-porosity flow. Despite the fact that hydraulic conductivity changed strongly with applied stress, the block diffusion times were found to be much less sensitive to compression. A simple conceptual model, whereby flow is dominated by sub-parallel low permeability obstructions which define predominantly horizontally aligned less mobile zones, is able to explain this result. Compression tends to narrow the gap between the obstructions, but not significantly alter the horizontal length scale. Irrespective of knowledge of the true flow pattern, these results show that simple models of solute flushing from landfill which do not include depth dependent changes in solute transport parameters are justified.

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Section: Simulation Of Bromide Breakthroughsupporting

confidence: 87%

Section: Simulationmentioning

confidence: 99%

Investigating the effect of compression on solute transport through degrading municipal solid waste

et al. 2014

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“…During a flow process through a heterogeneous porous medium, a major part of the solution is transported through some wider channels, making solute molecules move rapidly, a phenomenon called preferential flow (Rosqvist and Destouni, 2000;Gerke, 2006). More preferential flow can be expected in soils with natural structure (Dousset et al, 2007), corroborating the differences observed in transport parameters, especially in reference to dispersivity, as larger values of dispersivity are associated with a predominance of preferential flow (Aggelopoulos and Tsakiroglou, 2008).…”

Section: Breakthrough Experimentsmentioning

confidence: 73%

Retention and Solute Transport Properties in Disturbed and Undisturbed Soil Samples

Silva

Lier

Corrêa

et al. 2016

Rev. Bras. Ciênc. Solo

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Solute transport parameters can be determined in miscible displacement experiments, usually performed in columns with disturbed (sieved) soil samples. Experiments with undisturbed samples are uncommon, due to the difficulty of taking undisturbed samples at the size required for these experiments. Structural alteration of the disturbed material implies modifications in the pore geometry that determines hydraulic properties, including hydraulic conductivity and retention and properties related to miscible displacement. An existing model for prediction of breakthrough curves based on retention properties was tested using material from a medium-textured Ferralsol, and alterations caused by sample disturbance were investigated. Soil water retention curves and miscible displacement parameters were determined in breakthrough experiments with nitrate salts in columns filled with undisturbed and disturbed soil samples. Data obtained from the undisturbed samples showed a higher dispersion, suggesting homogenization of pore geometry and a reduction in the representative elementary volume by the disaggregation and sieving of the soil material. The transport parameters for nitrate determined in disturbed and undisturbed samples were significantly different and the model was able to simulate the observed breakthrough curves after fitting the pore connectivity parameter.

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“…ADE also performed better than MIM with consideration of reactions, although the experimental data exhibited considerable heterogeneity in percolation rate and solute concentrations in undisturbed soils [4] . However, in some other studies, dispersivity obtained from fitting ADE was extremely high, which might not be physically meaningful [5].…”

Section: Introductionmentioning

confidence: 87%

Comparison of the performance of traditional advection-dispersion equation and mobile-immobile model for simulating solute transport in heterogeneous soils

Hu¹,

Mao²

2016

Front. Agr. Sci. Eng.

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The traditional advection-dispersion equation (ADE) and the mobile-immobile model (MIM) are widely used to describe solute transport in heterogeneous porous media. However, the fitness of the two models is casedependent. In this paper, the transport of conservative, adsorbing and degradable solutes through a 1 m heterogeneous soil column under steady flow condition was simulated by ADE and MIM, and sensitivity analysis was conducted. Results show that MIM tends to prolong the breakthrough process and decrease peak concentration for all three solutes, and tailing and skewness are more pronounced with increasing dispersivity. Breakthrough curves of the adsorbing solute simulated by MIM are less sensitive to the retardation factor compared with the results simulated by ADE. The breakthrough curves of degradable solute obtained by MIM and ADE nearly overlap with a high degradation rate coefficient, indicating that MIM and ADE perform similarly for simulating degradable solute transport when biochemical degradation prevails over the mass exchange between mobile and immobile zones. The results suggest that the physical significance of dispersivity should be carefully considered when MIM is applied to simulate the degradable solute transport and/or ADE is applied to simulate the adsorbing solute transport in highly dispersive soils.

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Solute transport through preferential pathways in municipal solid waste

Cited by 74 publications

References 26 publications

Investigating the effect of compression on solute transport through degrading municipal solid waste

Investigating the effect of compression on solute transport through degrading municipal solid waste

Retention and Solute Transport Properties in Disturbed and Undisturbed Soil Samples

Comparison of the performance of traditional advection-dispersion equation and mobile-immobile model for simulating solute transport in heterogeneous soils

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