Simulation of multispecies biofilm development in three dimensions

A mathematical model to simulate the three-dimensional growth of multispeci es anaerobic biofilms is developed and tested with a two-species biofilm co mposed of sulfate-reducing bacteria and methanogens. The numerical approach is based on the separation of biological, physical, and chemical phenomena so that quasi-steady-state conditions can be used in the solution. Simulat ions with Desulfovibrio vulgaris and Methanobacterium formicicum result in the formation of a biofilm heterogeneous in structure and composition. The model predicts different biofilm structures in the absence of sulfate, when a syntrophic association between the two organisms develops, and in the pr esence of sulfate, when the two organisms compete for the available hydroge n. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.