Capturing the Pervasive and Controlling Effects of Diffusion on Solute Transport in Groundwater: Experiments & Modeling
Mixing processes significantly affect and limit reactive transport of contaminants in the subsurface. The correct quantification of mixing in heterogeneous groundwater systems needs to take into account the effects of diffusion at different scales. We investigated diffusion and compound-specific mixing effects at different scales (Fig. 1), including: (i) the pore scale (~ 10-2 m), (ii) the laboratory bench scale (~ 100 m) and the field scale (~ 102 m). Fig. 1. Scales of interest for solute transport in groundwater. In this talk I will present some of the results we have obtained in investigating both conservative and mixing-controlled reactive transport using pore-scale modeling, flow-through laboratory experiments and field-scale numerical modeling in complex heterogeneous hydraulic conductivity fields. I will also introduce some entropy-based metrics of mixing that were proposed to appropriately quantify dilution and reactive mixing of solute plumes. The talk will also illustrate recent experimental findings showing important diffusion effects for (i) stable isotope fractionation of common groundwater contaminants; (ii) transport of groundwater major ions and associated Coulombic interactions; and (iii) the investigation of dimensionality effects and mixing enhancement in 2-D vs. fully 3-D domains.
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Capturing the Pervasive and Controlling Effects of Diffusion on Solute Transport in Groundwater: Experiments & Modeling
Abstract
Mixing processes significantly affect and limit reactive transport of contaminants in the subsurface. The correct quantification of mixing in heterogeneous groundwater systems needs to take into account the effects of diffusion at different scales. We investigated diffusion and compound-specific mixing effects at different scales (Fig. 1), including: (i) the pore scale (~ 10-2 m), (ii) the laboratory bench scale (~ 100 m) and the field scale (~ 102 m).
Fig. 1. Scales of interest for solute transport in groundwater.
In this talk I will present some of the results we have obtained in investigating both conservative and mixing-controlled reactive transport using pore-scale modeling, flow-through laboratory experiments and field-scale numerical modeling in complex heterogeneous hydraulic conductivity fields. I will also introduce some entropy-based metrics of mixing that were proposed to appropriately quantify dilution and reactive mixing of solute plumes. The talk will also illustrate recent experimental findings showing important diffusion effects for (i) stable isotope fractionation of common groundwater contaminants; (ii) transport of groundwater major ions and associated Coulombic interactions; and (iii) the investigation of dimensionality effects and mixing enhancement in 2-D vs. fully 3-D domains.
