HR: 0800h
AN: H11E-0342    [Abstracts]
TI: Biofilm Growth Induced Transformation of Porous Media Dynamics
AU: Gage, J P
EM: justin_g@erc.montana.edu
AF: Department of Chemical and Biological Engineering Montana State University, 306 Cobleigh Hall PO Box 173920, Bozeman, MT 59717 United States
AU: * Seymour, J D
EM: jseymour@coe.montana.edu
AF: Department of Chemical and Biological Engineering Montana State University, 306 Cobleigh Hall PO Box 173920, Bozeman, MT 59717 United States
AU: Codd, S L
EM: scodd@coe.montana.edu
AF: Department of Chemical and Biological Engineering Montana State University, 306 Cobleigh Hall PO Box 173920, Bozeman, MT 59717 United States
AU: Gerlach, R
EM: robin_g@erc.montana.edu
AF: Center for Biofilm Engineering Montana State University, 366 EPS Building P.O. Box 173980, Bozeman, MT 59717 United States
AB: Magnetic resonance microscopy (MRM) has been applied to study hydrodynamic dispersion in porous media impacted by biofilms growth. MRM measures the averaged propagator of motion which provides the probability of displacements to occur over experimentally controlled times. The transition from pre-asymptotic to asymptotic hydrodynamic dispersion in a homogeneous porous medium constructed from monodisperse spheres is clearly visualized by the time evolution of the propagator to a Gaussian distribution. The growth of biofilms in the porous media induces a transition in the hydrodynamic dispersion from normal to anomalous transport which is visualized by the propagator transition from Gaussian to that modeled by a subdiffusive fractal kinetics model based on continuous time random walks (CTRW's). This transition is consistent with the porous media structure changing from homogeneous to nonhomogeneous and connections to fractal dimensions are discussed. The MRM data can be analyzed in the q-space domain, i.e. the wavelength space reciprocal to displacement, and provides information on the dynamics on scales above and below a single pore. Fractional kinetics models for subdiffusive processes predict stretched exponential Gaussian behavior and the q-space data fits to strectched exponentials exhibit a transition from Gaussian to subdiffusion due to biofilm growth.
DE: 1899 General or miscellaneous
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting