Groundwater pollution by organic compounds: A three-dimensional boundary element solution of contaminant transport equations in stratified porous media with multiple non-equilibrium partitioning
Ah. Elzein et Jr. Booker, Groundwater pollution by organic compounds: A three-dimensional boundary element solution of contaminant transport equations in stratified porous media with multiple non-equilibrium partitioning, INT J NUM A, 23(14), 1999, pp. 1733-1762
Citations number
51
Categorie Soggetti
Geological Petroleum & Minig Engineering
Journal title
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
Industrial contaminants and landfill leachates, particularly those with hig
h organic content, may migrate into groundwater streams under conditions of
non-equilibrium partitioning. These conditions may either be induced by ti
me-dependent sorption onto the soil skeleton and intra-sorbent diffusion in
the soil matrix, or by heterogeneous advective fields within the pore. The
se processes are known as chemical and physical non-equilibrium processes r
espectively, and may result in significant deviations from the paths predic
ted by steady-state partitioning assumptions. In addition, multi-directiona
l soil properties, soil stratification and complex geometries of the pollut
ion source may require a full three-dimensional analysis for accurate conta
mination prediction.
A three-dimensional boundary element solution of the time-dependent diffusi
ve/advective equation in non-homogeneous soils with both physical and chemi
cal non-equilibrium processes is developed. Saturated conditions and rate-l
imited mass transfer are assumed. The Laplace transform removes the need fo
r time-stepping and the associated numerical complexity, and the use of Gre
en's functions yields accurate solutions of infinite and semi-infinite doma
ins such as soils as well as media with finite dimensions. The solution req
uires boundary discretization only and can therefore be a valuable tool in
bio-remediation and landfill design where different geometries, soil proper
ties and pollutant loads may be analysed at low cost. The proposed techniqu
e is validated by comparing its predictions to analytical solutions obtaine
d for different types of soil and contaminant sources. The scope of the met
hod is illustrated by analysing the contamination of multi-layered soils by
a neighbouring river-and a surface source. Copyright (C) 1999 John Wiley &
Sons, Ltd.