Effects of “soil-like” particle size on gas transport and water retention properties in aged municipal solid waste from a Sri Lankan open dumpsite

Authors

M. Shanujah
T.K.K. Chamindu Deepagoda
A. K. Karunarathna
M. C. M. Nasvi
V. Shreedharan
G. L. S. Babu
Kathleen M. Smits
Curtis M. Oldenburg

Document Type

Article

Source Publication Title

Soil Science Society of America

DOI

http://dx.doi.org/10.1002/saj2.20100

Abstract

Open dumps constitute a major source of greenhouse gases (GHGs), predominantly methane and carbon dioxide, in developing countries. In an aged dump, typical waste composition is dominated by the “soil-like” fraction of which physical, hydraulic and gas transport characteristics markedly affect GHG emissions. This study characterized soil-gas diffusivity (Dp/D0), soil-water characteristics (SWC), and particle size distribution in “soil-like” fractions of aged solid waste retrieved at 2.5–5 m depth from an old open dumpsite situated at Kurunegala, Sri Lanka. The “soil-like” fraction was proportioned into three groups based on particle size (0–4.75, 4.75–9.5, and 9.5–25 mm) to investigate the particle size effect on Dp/D0 and SWC. The simulated methane concentration profiles in different size groups were also examined using the transport simulator TOUGH2-EOS7CA based on the multiphase flow of multicomponent gas mixture (methane, water vapour and air) under dry and half-saturation conditions across a predefined temperature gradient. The results highlighted distinct two-region characteristics (i.e., inter-aggregate and intra-aggregate pore regions) in all three size fractions which could be adequately parameterized with existing and modified bimodal functions. We proposed a useful practical tool for estimating Dp/D0 for known mean particle size and volumetric water content in the absence of direct measurements. The results further revealed that Dp/D0 is particle-size dependent; however, Dp/D0 remained invariant across all size fractions at the volumetric water content of ~0.22–0.25 cm3 cm-3. Numerical results further showed a pronounced effect of particle size and soil moisture on gas transport properties.

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Publication Date

5-24-2020

Language

English

Comments

© 2020 The Authors. Published by the Soil Science Society of America.

License

This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.

Recommended Citation

Shanujah, M.; Chamindu Deepagoda, T.K.K.; Karunarathna, A. K.; Nasvi, M. C. M.; Shreedharan, V.; Babu, G. L. S.; Smits, Kathleen M.; and Oldenburg, Curtis M., "Effects of “soil-like” particle size on gas transport and water retention properties in aged municipal solid waste from a Sri Lankan open dumpsite" (2020). Civil Engineering Faculty Publications. 12.
https://mavmatrix.uta.edu/civilengineering_facpubs/12