(549e) Effective Properties of Real Biofilm Shell

Biofilms are involved in several natural or engineered systems. Their presence within porous media can substantially affect the hydrodynamic and the transport process. In this work, considering a simple porous medium including a real biofilm structure, we describe a complete work-flow to numerically evaluate effective properties of the medium.

We analyze the influence of a multi-species basal biofilm developed over a plastic bead with a diameter of three millimeters. The biofilm thickness is close to one millimeter. The biofilm shell used for this study is generated under control in laboratory conditions and imaged using x-ray computed micro-tomography with a resolution of nine millimeters cube per voxel.

Several important preprocessing steps are necessary to achieve direct numerical simulations, including image processing and mesh generation. In order to evaluate the effectives properties (permeability and effective diffusion) of this porous medium, we consider first biofilm as impermeable (solving Stokes equations), and as a porous medium in a second time (using a fictitious domain approach).

Theses different approaches are compared and also permit simple geometric optimization.