UNS Collaborative Research: Optimizing Microfilter Productivity During Water Treatment: Modeling and Experimental Verification
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1510743 Cogan 1510526 Chellam This collaborative project results from the excellent filtered water quality of microfiltration membranes which are increasingly implemented for environmental and industrial water/wastewater separations. Tremendous effort has been spent studying fouling mechanisms during microfiltration; however, membrane fouling control by backwashing and air scouring remain largely unexplored topics. This work builds upon the PIs significant past collaborations to develop models of membrane processes. The proposed research will yield a rigorous mathematical framework along with systematic experimental validation to maximize microfiltration water productivity by maintaining high flux with periodic regeneration and electrocoagulation/flocculation pretreatment. This project provides a unique perspective to train students at all levels in multidisciplinary studies and broadening participation in science and engineering. The proposed research represents a synergistic collaboration between an experimentalist with expertise in membrane filtration and a mathematician with long-term expertise in modeling, fluid dynamics, and optimal control to make potentially transformative contributions to fouling control. The PIs tackle the problem of maximizing the cumulative volume of surface water filtered by hollow-fiber microfiltration incorporating periodic regeneration using optimal control theory. This study also includes sensitivity analysis and data assimilation, complementary mathematical processes used to quantify aspects of variability that arise in both theoretical and experimental studies due to underlying stochastic processes, uncertainty in measurements, or errors in approximations. Complementary laboratory measurements are aimed at generating necessary data for model validation as well as novel interfacial chemical characterization, to discern the sequence of mechanisms that lead to (ir)reversible fouling. Additionally, experiments and modeling will encompass Lake Houston water pretreated using an innovative electrochemical process, namely electrocoagulation with sacrificial aluminum electrodes. The underlying mathematical approach requires specific experimental measurements to determine sensitivity rankings for parameters (and hence physical quantities), statistical likelihood estimates for parameter distributions, and advanced optimal control analysis. Similarly, the experimental approach requires predictions such as key parameter regimes to explore, specific areas of uncertainty that can be reduced, and validation experiments to consolidate the real-world behavior with the mathematical predictions. This is facilitated by seamless collaboration, established over the past seven years or so, that brings together substantial experience on experimental and theoretical aspects to the project. Input will also be obtained from external stakeholders including a membrane manufacturer (Pall Corporation) and a water purveyor (Orange County Water District) who will provide hollow fibers as well as operational data from their long-term pilot-studies. They will also evaluate our methods and results to attempt to increase the productivity during low-pressure membrane filtration.
