Two-dimensional simulations of biofilm development: Effects of external environmental conditions

A new approach to biofilm modeling based on cellular automata was described . Simple. local rules governing cell growth and erosion generated self-orga nized biofilm structures. In numerical experiments, the morphologies of sim ulated biofilms depended primarily on the thickness of the concentration bo undary layer that controlled the external mass transfer. The bulk nutrient concentration had a weaker influence. For thin boundary layers, compact, de nse base biofilms were generated. Thick boundary layers produced ramified d endritic structures with higher porosities. For the same value of a critica l bulk nutrient concentration, biofilm structures, generated in individual simulations, varied randomly between two very different outcomes: a dense, thick layer or almost complete erosion. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.