HR: 0800h
AN: H31F-1358    [Abstracts]
TI: Contrasting Particle Clogging in Soils and Granular Media Filters
AU: * Mays, D C
EM: david.mays@cudenver.edu
AF: University of Colorado at Denver, Department of Civil Engineering 1200 Larimer Street, Denver, CO 80217-3364 United States
AB: Deposition of colloidal particles leads to permeability reduction (or clogging) in the soil geomembrane, which reduces fluxes, alters flow patterns, and limits both colloid-associated contaminant transport and delivery of colloidal reactants for purposes of remediation. Comparison of experimental results for soils and granular media filters reveals qualitatively different clogging phenomena with regard to (1) particle stabilization, (2) fluid velocity, and (3) the fractal dimension of particle deposits. These differences have important implications for contaminant hydrology, because the classical approach for understanding particles in natural environments is taken from the filtration literature, which is based on clean granular media. Accordingly, many of the relevant experiments have been performed with granular filters using media such as glass beads or quartz sand. In such filters, clogging is associated with destabilized particles, slower fluid velocity and deposits with smaller fractal dimensions. In contrast, in soils clogging is associated with stabilized particles, faster fluid velocity and deposits with larger fractal dimensions. With regard to these variables, soils are opposite to filters but identical to cake filtration. Numerous examples will be presented from the filtration literature and the soil science literature to illustrate these differing viewpoints. This analysis demonstrates that experiments on clean granular media filters should not be expected to predict particle clogging in soils, sandstones or other natural porous materials containing more than a few percent fines.
DE: 0418 Bioremediation
DE: 1828 Groundwater hydraulics
DE: 1832 Groundwater transport
DE: 1865 Soils (0486)
SC: Hydrology [H]
MN: Fall Meeting 2005