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

水和废水超滤中膜污染的建模和控制

• 批准号: RGPIN-2019-05644
• 负责人: Lohi, Ali
• 金额: $ 2.4万
• 依托单位: Ryerson University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=715690
• 关键词: Modelling; Control; Membrane; Fouling; Ultrafiltration

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.

膜过滤，如超滤（UF），是一种高效节能的工艺，已广泛应用于水净化、废水处理、生物技术和水包油乳液分离等领域。然而，进料溶液中溶质/颗粒造成的膜污染是该行业面临的主要挑战，并且存在目前阻碍膜过滤广泛应用的操作问题。膜污染会导致渗透通量随着时间的推移而降低，导致过滤效率低下和过滤成本较高。 涂料制造商的废水含有多种物质，例如：有机/无机颜料、乳胶、溶剂和乳化剂。用超滤处理乳胶漆废水会导致结垢，从而导致水力阻力显着增加、渗透通量下降和跨膜压力 (TMP) 增加。通过我们之前的研究，我们开发了机械模型来预测使用均匀和非均匀孔径膜的膜污染、TMP 和功耗。我们还开发了创新的污垢修复技术，能够控制乳胶废水错流超滤中的膜污垢。为了进一步发展中试规模和工业应用中的节能，仍然需要深刻理解以下机制：i）孔表面的颗粒滞留（孔收缩）； ii) 附着在膜表面导致部分或完全堵塞孔入口（形成滤饼）； iii) 颗粒聚集导致结块堆积； iv) 滤饼层中的颗粒破碎行为并重新进入滞留物，及其对结垢的影响。 本研究的目的是使用计算流体动力学和离散元方法 (CFD-DEM) 模拟板框膜孔内和表面上的颗粒沉积与膜污染现象的关系。计算粒子到其最终捕获位置的轨迹涉及流体动力学和表面相互作用。 DEM 将与 CFD 相结合，研究膜污染过程中发生的流体-颗粒相互作用系统，其中溶质（固相）和溶液（流体）相都有助于流动动力学和颗粒沉积。通过该研究计划彻底了解这种现象并开发减少膜污染的新颖和创新技术对于行业非常重要。 拟议研究计划的主要好处是开发设计分离/过滤膜的创新技术/方法。这种新颖的方法将通过结合我们的机械污垢附着模型和 CFD-DEM 模型来实现。所开发的方法将对加拿大膜制造商和膜用户产生重大影响。为加拿大工业界提供 HQP 培训是拟议研究计划的另一个好处。