HR: 1340h
AN: H53E-1466    [Abstracts]
TI: Spatial Distribution of Biomass in Porous Media
AU: * Jansik, D P
EM: jansikd@engr.orst.edu
AF: Department of Chemical, Biological and Environmental Engineering, Oregon State University, 220 Owen Hall, Corvallis, OR 97331,
AU: Wildenschild, D
EM: dorthe@engr.orst.edu
AF: Department of Chemical, Biological and Environmental Engineering, Oregon State University, 220 Owen Hall, Corvallis, OR 97331,
AU: Wood, B
EM: Brian.Wood@oregonstate.edu
AF: Department of Chemical, Biological and Environmental Engineering, Oregon State University, 220 Owen Hall, Corvallis, OR 97331,
AB: Current understanding of subsurface microbial biofilm formation and their impact on fluid hydrodynamics is limited by our ability to observe the microscale geometry of developed biofilms. Biomass distribution in porous media has been observed previously in only two dimensional systems; currently, no high-resolution 3- dimensional datasets exist that give sufficient information about microbial distribution such that the impact on flow and transport at the microscale can be directly computed. Three dimensional biofilms can significantly alter pore flow velocities and overall mass transfer between the aqueous and biological phases. We are currently developing new methods to resolve high-resolution 3-dimensional tomographic images of biofilms in porous media using synchrotron based x-ray microtomography. Imaging biofilms without disturbing their natural spatial arrangement has been a challenging task, primarily because most conventional dopants that dissolve in water also easily diffuse into biofilms. One method that we have developed to overcome this problem is the addition of silver nanoparticles to the fluid phase. Using this approach, we have been able to differentiate between the biomass filled pore space and fluid filled pore space. To date, the images that we have collected have yielded good representations of the geometry and qualitative information about structures of biomass. Ultimately, we intend to combine this kind of experimental measurement with upscaling (via volume averaging) to determine how biofilms might alter the physical properties of the porous media. Ultimately, by quantifying the spatial distribution of biofilms we will gain a greater understanding of how changes in physical parameters may impact the rate at which microbes degrade contaminants or produce products, and therefore this research has applications to bioremediation and bioprocessing.
DE: 1805 Computational hydrology
SC: Hydrology [H]
MN: 2007 Fall Meeting