TU Delft

Biofilm growth pattern in honeycomb monolith packings: Effect of shear rate and substrate transport limitations

Sirous Ebrahimi (1), Cristian Picioreanu (1), Joao B. Xavier (1), Robbert Kleerebezem (1), Michael Kreutzer (2), Freek Kapteijn (2), Jacob A. Moulijn (2), Mark C.M. van Loosdrecht (1)

(1) Department of Biotechnology, Delft University of Technology
Julianalaan 67, 2628 BC Delft, The Netherlands.
Tel: +31-(0)15-2781551, Fax: +31-(0)15-2782355

(2) Department of Chemical Engineering, Delft University of Technology
Julianalaan 136, 2628 BL Delft, The Netherlands

*Corresponding author. E-mail: Sirous.Ebrahimi@EPFL.ch
Currently at Ecole Polytechnique de Lausanne
Tel: +41-6935728, Fax: +41-6934722

This web page contains support material for our paper entitled
"Biofilm growth pattern in honeycomb monolith packings: Effect of shear rate and substrate transport limitations".
Catalysis Today, 105(3-4):448-454, 2005.

This page contains video files of the simulations presented in the paper.

2D simulations of biofilm formation in monolith reactors

  Day 0  Day 0   Day 7  Day 7

Day 14  Day 14  Day 20  Day 20

The above show the simulated development in time of the biofilm in square monolith channels (at days 0, 7, 14, and 20, respectively). Substrate concentration field is shown by contour lines and by gray areas with a shade gradually changing from white (maximum concentration) to dark gray (minimum concentration). Arrows represent substrate fluxes and the arrow length is proportional with the flux value.

Click on image below to see an animation of the simulated biofilm development.
The movie was encoded with DivX5.2. To view this movie you must install the freeware DivX5.2 (get it here).

Biofilm development movie

It can be clearly seen that the top of biofilm structure in the middle of the channel wall receives larger substrate fluxes, this leading to larger biomass growth rates than in the corners. This trends can be also observed for the biofilms formed in the experimental setup (pictures below).

         Initial  Day 0 experimental   First week  First week

Second week Second week   Third week  Third week

The biofilm patterns obtained depend on the thickness of hydrodynamic and mass transfer boundary layers.
Consequently, substrate concentration fields and shear stresses on the biofilm surface can be calculated from the liquid velocity fields.  Liquid velocity (left images), substrate concentration (middle images) and liquid shear (right images) are shown below for two moments in time. Besides biofilm growth, also biofilm detachment was applied.

MonolithVelocityMonolithConcentrationMonolithShear

MonolithVelocityMonolithConcentrationMonolithShear

 

2005 - Biofilm modelling group at the TU Delft