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Forward and Back Diffusion from Low Permeability Zone: A Review of Analytical Solutions with Different Boundary Conditions
저투수성 매체 내 오염물질의 정확산과 역확산: 경계조건에 따른 용질이동 해석해의 소개
Econ. Environ. Geol. 2020 Feb;53(1):99-110
Published online February 28, 2020;
Copyright © 2020 the Korean society of economic and environmental gelology.

Changmin Kim1 and Minjune Yang2*
김창민1 · 양민준2*

1Division of Earth Environmental System Sciences, Pukyong National University, Busan 48514, South Korea
2Department of Earth and Environmental Sciences, Pukyong National University, Busan 48514, South Korea
1부경대학교 지구환경시스템과학부, 2부경대학교 지구환경과학과
Received January 3, 2020; Revised January 26, 0202; Accepted February 11, 2020.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
It is a global trend to consider contaminated low-permeability zones as one of the primary management targets for the remediation of DNAPL contaminated sites. In addition, studies on the persistence caused by back diffusion of DNAPLs from low-permeability zones have been actively conducted worldwide. On the other hand, the studies for domestic groundwater contamination with the low-permeability zones are insufficient. Therefore, this study introduces the forward and back diffusions of DNAPL through low-permeability zones and suggests the importance of them by reviewing representative previous studies, especially on back diffusion and plume persistence. We proposed six diffusion scenarios and analytical solutions based on various boundary conditions of low-permeability zones. FI (forward diffusion into infinite domain) and BI (back diffusion form infinite domain) scenarios illustrate forward and back diffusion in which the depths of a low-permeability layer are assumed to be infinite. FFN (forward diffusion into finite domain with no flux boundary) and BFN (back diffusion from finite domain with no flux boundary) scenarios describe forward and back diffusion for a finite domain of a low-permeability layer with no flux boundary at the bottom. When the bottom of a low-permeability layer is considered as flux boundary, forward and back diffusion scenarios correspond to FFF (forward diffusion into finite domain with flux boundary) and BFF (back diffusion from finite domain with flux boundary). The scenarios and analytical solutions in this study may contribute to the determination of an efficient remediation method based on site characteristics such as a thickness of low-permeability zones or duration of contamination exposure.
Keywords : forward diffusion, back diffusion, low-permeability zone, DNAPL, analytical solution


April 2020, 53 (2)