New York, New York
November 1, 2019
November 1, 2019
November 30, 2019
7
10.18260/1-2--33806
https://peer.asee.org/33806
392
Benjamin Wallen is a Lieutenant Colonel in the United States Army and an Assistant Professor in the Department of Geography and Environmental Engineering at the United States Military Academy. He is a 1996 graduate of the United States Military Academy with a B.S. in Environmental Engineering and obtained an M.S. from both the University of Missouri at Rolla in Geological Engineering and the University of Texas at Austin in Environmental Engineering. Most recently, he graduated with his Ph.D. from the Colorado School of Mines in Civil and Environmental Engineering. He teaches Water Resources and Planning, Environmental Science, and Environmental Engineering Technologies.
Andrew Ng is a Captain in the United States Army and an Instructor in the Department of Geography and Environmental Engineering at the United States Military Academy. He is a 2010 graduate of the United States Military Academy with a B.S. in Environmental Engineering with honors and a 2019 graduate from the University of California, Berkeley with an M.S. in Civil and Environmental Engineering. He teaches Environmental Engineering for Community Development, Environmental Engineering Technologies, and Environmental Biological Systems.
Michael A. Butkus is a professor of environmental engineering at the U.S. Military Academy. His work has been focused on engineering education and advancements in the field of environmental engineering. His current research interests are in physicochemical treatment processes with recent applications in drinking water disinfection, lead remediation, sustainable environmental engineering systems, and contaminant transport. Butkus is a Board Certified Environmental Engineer and he is a registered Professional Engineer in the state of Connecticut.
Erick Martinez is a Major in the United States Army and an Assistant Professor in the Department of Chemistry and Life Science at the United States Military Academy. He is a 2007 graduate of the United States Military Academy with a B.S. in Environmental Engineering and a 2016 graduate of the University of Florida with an M.E. in Environmental Engineering. He is a registered Professional Engineer (P.E.) in the State of Florida. He teaches General Chemistry, Environmental Engineering for Community Development, Environmental Science, and Environmental Engineering Technologies.
Jeremy received his B.S. in Civil Engineering from the University of South Florida in 1998, his M.S. in Environmental Health Sciences from the University of Michigan, Ann Arbor in 2013, and his Ph.D. in Civil Engineering at Wayne State University in 2018.
He is currently an Experimenter for the Army responsible for performing fundamental research and development to advance the state-of-the-art in the field of membrane separation, advanced water treatment and reuse. He is the Principal Investigator on funded In-house Laboratory Independent Research (ILIR) to use Integrated Micromixers and Acoustic Streaming to Prevent Reverse Osmosis Membrane Fouling. The objective of this research is to obtain a greater knowledge of the fundamental physics, chemistry, fluid mechanics, and acoustic streaming principles associated with bubble based acoustic mixing at the RO membrane surface.
The demand for clean, safe drinking water continues to grow at near-exponential rates as a function of both the burgeoning world population and depletion of easily accessible water sources. As a result, research into improvements into desalination capabilities is swiftly increasing as the ocean represents an infinite supply of water conveniently located to the most densely populated portions of the world, providing a simple answer to growing municipal water demands. One method to improve desalinization processes involves reducing scaling within reverse osmosis (RO) membranes. With reduced scaling, membrane permeability remains higher reducing the energy bill required per volume of water treated. Associated impacts also include reduction in cost to replace RO filters impacting traditional water treatment plants as well as Reverse Osmosis Water Purification Unit (ROWPU) used in austere environments. Two different centers (the Center for Environmental and Geographic Sciences at the United States Military Academy and the U.S. Army Tank Automotive Research, Development and Engineering Center in Warren, MI) are conducting research in this area that enables enrichment of the undergraduate experience. The partnership between the two centers provides a link between industry need and undergraduate research. The research provides an additional capstone-type experiential learning opportunity for students which incorporates a three-week summer internship and a one or two-semester long independent study experience for environmental engineering students. The purpose of this study is to examine the impact of different feed spacer geometries that separates membranes within RO filters in order to increase filtration efficiency and requires students to develop innovating solutions in a group project work setting. A model was developed in SolidWorks using Flow Simulation to replicate the hydrodynamic conditions within a cell (Sterlitech SEPA Crossflow Cell, 316SS) to match an experimental configuration set up. The initial model evaluated changes in flow velocity and pressure. Subsequent model refinement enabled the evaluation of the impact of three different geometries on flow regimes with significant parameters investigated that included pressure drop within the cell, flow velocities, flux, and dead zones. Selection of the three different geometries evaluated was based upon the ability to reduce dead zones and streamline flow velocities thus minimizing the conditions necessary for scale to form. Experiments were conducted to validate the response of designed and 3D printed feed spacers placed in identical cell compared to modelled results. A feed solution of 0.0304 M CaCl2 and 0.0304 M Na2SO4 was used to evaluate scaling within a 24-hour period for each of the different geometries. Detailed data of the different spacer geometries was obtained through physical testing and computer modeling. Preliminary experimental results indicate a correlation between changes in designed feed spacers and scaling associated with decreased flow velocities and increased dead zones. Experiments and modeling efforts over the coming months are designed to enable further validation of the model and in so doing enable improved efficiencies toward the redesign of feed spacer geometry.
Wallen, B. M., & Espell, W. E., & Hanna, A. M., & Ng, A. J., & Butkus, M. A., & Martinez, E., & Swanton, P. T., & Walker, J. S. (2019, November), Modelling and Experimental Investigation of Geometric Solutions to Scaling on Reverse Osmosis Membranes through innovative Feed Spacer Design Paper presented at 2019 Fall Mid Atlantic States Conference, New York, New York. 10.18260/1-2--33806
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