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|Title:||Transport of Kinetically Adsorbing Contaminants in Randomly Heterogeneous Aquifers|
|Author(s):||Quinodoz, Hernan Alfonso Maria|
|Doctoral Committee Chair(s):||Valocchi, Albert J.|
|Department / Program:||Civil Engineering|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
Engineering, Sanitary and Municipal
|Abstract:||One of the most promising approaches for modeling solute transport in heterogeneous aquifers describes the natural variability in hydraulic conductivity by means of a stationary random field. Therefore, the solute concentration distribution at a given time also becomes a random field. For the case of an inert solute, Dagan found a solution for the temporal evolution of the ensemble spatial moments of the concentration random field; this solution describes the impact of small-scale heterogeneity upon large-scale spreading of the plume (the so-called macrodispersion phenomenon). We extend Dagan's results to the case of a reactive solute undergoing linear reversible adsorption. We assume spatially uniform kinetic rate coefficients. The solution obtained explicitly quantifies the combined effect of nonequilibrium adsorption reactions and macrodispersion, for a range of possible time scales of both processes. We show that for very large times the effects of macrodispersion and kinetics are additive, while for shorter times they are related in a nonlinear fashion. As a particular application of the theory, we demonstrate that the conditions necessary for the existence of local equilibrium depend not only on the kinetic rate coefficients but also upon the spatial structure of the conductivity field.
A numerical model was also developed and used to test the new theory. Results from all numerical experiments show excellent agreement with the theoretical results. We have analyzed data from a large-scale field experiment of contaminant transport at Borden (Ontario, Canada). The observed behavior of an adsorbing solute used in this experiment is consistent with the predictions of the new theory.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1992.
|Date Available in IDEALS:||2014-12-17|
This item appears in the following Collection(s)
Dissertations and Theses - Civil and Environmental Engineering
Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois