Modelling and Control of Membrane Fouling in Ultrafiltration of Water and Wastewater

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Membrane filtration, such as ultrafiltration (UF), is an efficient and energy saving process that has been widely used in water purification, wastewater treatment, biotechnology, and oil-in-water emulsion separation. However, membrane fouling by the solutes/particles in a feed solution is a major challenge for the industry and has operational concerns that are currently hindering widespread application of membrane filtration. Membrane fouling causes a reduction of the permeating flux with time, resulting low filtration efficiency and higher filtration cost.******Wastewater from paint manufacturers contains variety of substances, such as: organic/inorganic pigments, latex, solvents and emulsifying agents. Treatment of latex-paint wastewater with UF results in fouling, which causes a significant increase in hydraulic resistance, permeate flux decline and transmembrane pressure (TMP) increase. Through our previous studies, we have developed mechanistic models to predict membrane fouling, TMP, and power consumption using uniform and non-uniform pore size membranes. We also have developed innovative fouling remediation techniques capable of controlling membrane fouling in the cross-flow UF of latex effluent. For further development towards energy saving in pilot scale and industrial applications, there remains a need for a profound understanding of the following mechanisms: i) particle retention on the pore surface (pore constriction); ii) attachment on the membrane surface causing in blocking of the pore inlet, partially or completely (cake formation); iii) particle aggregation causing cake buildup; and iv) particle break-up behavior from the cake layers and reentering into retenate, and their effects on fouling.******The objective of the proposed research is to use Computational Fluid Dynamics and Discrete Element Method (CFD-DEM) to model the particle deposition on the plate-and-frame membrane, both inside the pore and on the surface, in relation to membrane fouling phenomena. Computing the trajectory of a particle to its final capture location involves both hydrodynamic and surface interactions. DEM will be coupled with CFD to study fluid-particle interaction systems occurring during membrane fouling in which both the solute (solid) and solution (fluid) phases contribute to the flow dynamics and particle deposition. A thorough understanding of this phenomenon and development of novel and innovative techniques to reduce membrane fouling through this research plan are of great importance to the industry.******Main benefit arising from the proposed research plan is development of an innovative technique/method in designing separation/filtration membranes. This novel method will be achieved by combining our mechanistic fouling attachment model and the CFD-DEM model. The developed method will have a major impact on Canadian membrane manufacturers and membrane users. Training of HQP for the Canadian industry is an added benefit of the proposed research plan.**