Original scientific paper
https://doi.org/10.17794/rgn.2021.2.3
SOLUTE TRANSPORT MODELLING IN LOW-PERMEABILITY HOMOGENEOUS AND SATURATED SOIL MEDIA
Muhammad Zaheer
orcid.org/0000-0001-9199-5880
; Department of Geology, Hazara University Mansehra 21300, Khyber Pakhtunkhwa, Pakistan; School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China
Hadayat Ullah
; Department of Geology, Hazara University Mansehra 21300, Khyber Pakhtunkhwa, Pakistan
Saad Ahmed Mashwani
; Department of Geology, Hazara University Mansehra 21300, Khyber Pakhtunkhwa, Pakistan
Ehsan ul Haq
; Department of Geology, Hazara University Mansehra 21300, Khyber Pakhtunkhwa, Pakistan
Syed Husnain Ali Shah
; Department of Geology, Hazara University Mansehra 21300, Khyber Pakhtunkhwa, Pakistan
Fawaz Manzoor
; Department of Geology, Hazara University Mansehra 21300, Khyber Pakhtunkhwa, Pakistan
Abstract
Fickian and non-Fickian behaviors were often detected for contaminant transport activity owed to the preferential flow and heterogeneity of soil media. Therefore, using diverse methods to measure such composite solute transport in soil media has become an important research topic for solute transport modeling in soil media. In this article, the continuous-time random walk (CTRW) model was applied to illustrate the relative concentration of transport in low-permeability homogeneous and saturated soil media. The solute transport development was also demonstrated with the convection-dispersion equation (CDE) and Two Region Model (TRM) for comparison. CXTFIT 2.1 software was used for CDE and TRM, and CTRW Matlab Toolbox v.3.1 for the CTRW simulation of the breakthrough curve. It was found that higher values of determination coefficient (R2) and lower values of root mean square error (RMSE) concerning the best fits of CDE, TRM, and CTRW. It was found that in the comparison of CDE, TRM, and CTRW, we tend to use CTRW to describe the transport behavior well because there are prevailing Fickian and non-Fickian transport. The CTRW gives better fitting results to the breakthrough curves (BTCs) when β has an increasing pattern towards 2.00. In this study, the variation of parameters in three methods was investigated and results showed that the CTRW modeling approach is more effective to determine non-reactive contaminants concentration in low-permeability soil media at small depths.
Keywords
Low permeability; relative concentration; non-Fickian; continuous-time random walk
Hrčak ID:
254167
URI
Publication date:
21.3.2021.
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