Matrix diffusion effects in the cleanup of heterogeneous aquifers
Simple mathematical models are developed to account for the rather slow mass transport of nonaqueous phase liquid (NAPL) into aqueous solution in groundwater during flushing operations. The models are based on the assumption that this bottleneck in the process is associated with diffusion in the aqueous phase in the porous medium from the location of the NAPL drops/ganglia in a region of relatively low permeability out into a region of substantially higher permeability, somewhat analogous to diffusion from a block of porous rock into a nearby fracture, where the fracture system overwhelmingly dominates the overall permeability. The models include batch flushing, flushing in a laboratory column, and a one-dimensional model for flushing by means of a single recovery well.
KeywordsPermeability Phase Liquid Porous Medium Aqueous Phase Environmental Management
Unable to display preview. Download preview PDF.
- DiGiulio, D.C., Cho, J.S., Dupont, R.R. and Kemblowski, M.W.: 1990, ‘Conducting Field Tests for Evaluation of Soil Vacuum Extraction Application’, Proc. 4th Natl. Outdoor Action Conf. on Aquifer Restoration, Ground Water Monitoring and Geophysical Methods, Las Vegas, NV, May 14–17, p. 587.Google Scholar
- Miller, C.T., Poirier-McNeill, M.M. and Mayer, A.S.: 1990, ‘Dissolution of Trapped Nonaqueous Phase Liquids: Mass Transfer Characteristics’,Water Resources Res. 26, 2783–2796.Google Scholar
- Mutch, R.D., Jr., Scott, J.I. and Wilson, D.J.: 1991, ‘Cleanup of Fractured Rock Aquifers: Implications of Matrix Diffusion’,Environmental Monitoring Assessment, in press.Google Scholar
- Powers, S.E., Loureiro, C.O., Abriola, L.M. and Weber, W.J., Jr.: 1991, ‘Theoretical Study of the Significance of Nonequilibrium Dissolution of Nonaqueous Phase Liquids in Subsurface Systems’,Water Resources Res. 27, 463–477.Google Scholar