The mechanistic aspects of microbial transport in porous media

A mechanistic model is constructed to account for colloidal filtration by incorporating fundamental intersurface forces between individual particle and collector, geometry and elastic properties of bacteria / particles, and flowrate of the electrolytic medium. Particle adhesion on the collector surface is derived from the DLVO theory based on electrostatic double layers and van der Waals attraction, while particle detachment depends on the hydrodynamic shear. Filtration efficiency, α, of a conventional packed column is estimated by numerically solving the governing convection-diffusion equation, and is shown experimentally dependent on both ionic concentration and flowrate of the electrolyte contrasting the classical colloid filtration theory. Model bacterial strains of Aeromonas punctata and Raoultella ornithinolytica were investigated using a conventional packed column test and a homemade microfluidic device. Their behavior were shown to be consistent with the model.