Study on Flow Pattern in a Membrane Bioreactor Using Image Analysis & Computational Fluid Dynamics

In municipal and industrial wastewater treatment, submerged membrane filtration units are used to reject suspended solids from water. Within this process, air bubbles are injected into the stationary suspension in order to remove the cake layer and by that to reduce permeate flux decline. Gas-liquid two-phase flow has been shown to be very effective in reducing fouling for different membrane modules with different feeds, including submerged flat sheet membranes used in membrane bioreactors for treatment of wastewater. Although gasliquid two-phase flow occurring on the lumen side of tubular or hollow-fiber membranes has been very well characterized, the two-phase flow regime in submerged membrane processes is different to that inside external membranes. Within this article, the advantages image analysis introduced and then Showing that hydrodynamic data obtained in 2D images can be used well for 3D Design, Simulation and modeling studies. An Eulerian two-fluid model was used to simulate two-phase flow conditions similar to those encountered in the experimental study. As expected the presence of membrane does not have significant effect on gas hold-up but the profiles of velocity and circulation velocity changed.