We will introduce a mathematical model for the dispersal phenomenon in multispecies biofilms. The model has been formulated as a free boundary value problem based on mass balance considerations.

In particular, the evolution of the particulate components constituting the biofilm is governed by a system of hyperbolic partial differential equations.

The diffusion and reaction of the dissolved components as well as the motility of the planktonic cells originating through the dispersal phenomenon are modelled by a system of semilinear parabolic equations.

The model has been studied through numerical simulations. In particular, three biological cases have been investigated. The first is related to dispersal induced by nutrient starvation. The second considers the dispersal triggered by the diffusion of a sub-lethal antibiofilm agent. The third example considers the case of dispersal induced by a self-produced biocide agent.