The role of filter media geometry in tap water biofilms

Biofilms are inextricably linked to the hydrodynamics of flow through a filter and yet engineers rarely explicitly engineer this interaction. We developed a system that links computer simulation and 3-D printing to optimize filter media geometry and biofilm function. The main objective is to prototype filter media to passively induce vortices that roll down a surface, imposing oscillating flow in the channel to enhance biofilm formation. Thus, a 2-D model was developed and linked to a 3-D printer. The model was solved to determine the wall shear stress distribution with time. The experiments showed that the thickest, densest and most extended biofilms were formed for the strongest oscillations in the channel due to the presence of a filter medium. This is a speeding-up innovation in the design and implementation of small-scale biofiltration systems for rural communities.