Abstract

A biofilm is an accumulation of microbial cells and inorganic compounds held together in a polymeric matrix and firmly attached to a substratum; its study has been focused to its description as a biological catalysts. Nevertheless, it is known that the presence of biofilms in flow systems is able to change hydrodynamic behaviour. This phenomenon could be associated to the presence of velocity profiles that cause convective flow inside the biofilm. Following this idea, in this work, the description of a biofilm as a permeable fixed bed pseudo-homogeneous chemical reactor is proposed in order to find concentration and velocity profiles inside the biofilm. The model is simplified by considering a constant acceleration field that provokes flow inside the biofilm. Depending on the velocity profile, concentration profiles of the substrate are predicted. This study considers laminar flow inside the biofilm, therefore it is not necessary to consider the possible compactation of the biofilm due to an increase of the resistance against drag by flow outside. It is assumed that the biofilm is thin enough to be represented using rectangular coordinates without regarding the actual geometry. Finally, first order Kinetics is considered for the substrate consumption; literature data is used to adjust the proposed model. Simulation results show that concentration profiles are clearly dispersed by the convective flow, because of the addition of two orthogonal contributions, the one depending on the reaction-diffusion phenomenon and the other depending on the convective flow inside the biofilm.

Recommended Citation

León-Becerril, Elizabeth and Maya-Yescas, Rafael (2007) "Modelling of Biofilm Reactors for Degradation of Water Pollutants," International Journal of Chemical Reactor Engineering: Vol. 5: A44.
Available at: http://www.bepress.com/ijcre/vol5/A44