ENVR 89 |
| Common framework describes membrane filtration as a combination of forward flux with filtered fluid and mechanisms moving the solids away from the membrane surface (backflux). We extend this model to dynamic conditions by assuming that a solid's network is formed adjacent to the membrane surface. The critical solid's concentration is theoretically derived from the percolation theory. The hydrodynamic stress leads to further network deformation and to a decrease in porosity and permeability. At some moment, the porosity of the solid's network becomes so small that the pores (voids) become disconnected and an impermeable cake is formed. Based on theoretical considerations, the loss of connectivity should be very rapid, reminiscent of a phase transition. Our model successfully describes such dramatic changes during “subcritical” fouling. Finally, the model is able to explain the effects of the time dependence of filtration resistance responses to biomass changes as observed in our experiments with dead-end filtration. |
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Membrane Technology for Water Treatment and Reuse
1:30 PM-5:10 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 237, Oral
Division of Environmental Chemistry |