Simulation on particle adhesion on simulated and modified drinking water biofilms

Abstract

Biofilms, commonly found in drinking water distribution system (DWDS), play an important role in pathogens transportation and persistent and raise concern on drinking water safety. They can harbor opportunistic pathogen from disinfectants added to control pathogen. Since bacterial adhesion is the prerequisite for further propagation, understanding the mechanisms of bacterial adhesion on biofilm surface is important to prevent pathogen adhesion and reduce the risk to exposure in DWDS. In this study, bacterial size particles were used to model bacterial adhesion on simulated drinking water biofilms surfaces. Simulations on effects of Brownian motion and drag force on adhesion mechanism were conducted using COMSOL Multiphysics. The role of surface topography and roughness on particle deposition were determined through simulations on biofilm surfaces and artificial surfaces maintaining roughness or topography similar to biofilms. The simulation results showed that surface topography instead of roughness and associated hydrodynamic condition can affect particle adhesion tendency. Spatial analysis through semivariogram showed that the deposition location was not dominated by surface structure.