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Functional relationships for the estimation of van Genuchten parameter values in landfill processes models
Jim White1, Kiriaki Zardava2, Dharumarajen Nayagum3
1Faculty of Engineering and the Environment, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
Waste Management (New York, N.Y.)
|January 10, 2015
Summary
This study provides van Genuchten parameters for modeling unsaturated landfill waste flow. New relationships link these parameters to saturated moisture content, improving waste moisture estimations in numerical models.
Area of Science:
- Geotechnical Engineering
- Environmental Engineering
- Hydrogeology
Background:
- Landfill processes require accurate estimation of capillary pressure and relative permeability in waste.
- Analytical equations, like the van Genuchten equations, are crucial for modeling unsaturated flow.
- Waste properties, including saturated moisture content, can vary significantly due to compression and degradation.
Purpose of the Study:
- To identify the range of van Genuchten parameter values for landfill waste.
- To propose a formulaic relationship between van Genuchten parameters and saturated moisture content.
- To investigate the impact of these relationships on numerical simulations of leachate recirculation.
Main Methods:
- Review of porous material behavior under unsaturated conditions.
- Application of van Genuchten capillary pressure function and Mualem's transform for relative permeability.
- Development of functional relationships using a database of existing results.
- 2D numerical model simulation of leachate recirculation.
Main Results:
- Established functional relationships between saturated moisture content and van Genuchten parameters.
- Simulations showed minor impact on boundary flows but influenced saturation distribution and recharge behavior.
- The impact on saturation and recharge was not significant enough to affect leachate recirculation system design.
Conclusions:
- The identified relationships enhance numerical modeling of unsaturated flow in landfills.
- While not drastically altering boundary flow, the relationships refine understanding of saturation dynamics.
- The findings suggest current leachate recirculation system designs are robust to these variations.
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