A two-dimensional numerical model for silica colloidal fouling in a spacer-filled reverse osmosis membrane system

A two-dimensional numerical model simulating colloidal particle deposition and fouling was developed by integrating fluid flow and solute mass transfer inside a reverse osmosis (RO) membrane feed channel. This model is able to animate the process of colloidal fouling accumulation by simulating the process of colloidal particles deposition on RO membrane surface and occupying the fluid zone into the porous cake zone. The cake layer was treated as homogeneous porous media domain with constant porosity. This model predicts the porous cake layer thickness distribution among membrane surface and its effects on the cake-enhanced osmotic pressure (CEOP). The performance of the RO membrane system under the influence of silica colloidal fouling in terms of initial permeate flux, channel Reynolds number, concentration of silica particles and feed spacers were investigated using this model. Model simulations are validated against experimental data of permeate fluxes with good agreement.