| NSF Org: |
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems |
| Recipient: |
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| Initial Amendment Date: | December 15, 2017 |
| Latest Amendment Date: | August 12, 2019 |
| Award Number: | 1752531 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Christina Payne
cpayne@nsf.gov (703)292-2895 CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems ENG Directorate for Engineering |
| Start Date: | August 1, 2018 |
| End Date: | July 31, 2023 (Estimated) |
| Total Intended Award Amount: | $547,364.00 |
| Total Awarded Amount to Date: | $547,364.00 |
| Funds Obligated to Date: |
FY 2019 = $112,380.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
1500 ILLINOIS ST GOLDEN CO US 80401-1887 (303)273-3000 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1500 Illinois Street Golden CO US 80401-1887 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Interfacial Engineering Progra |
| Primary Program Source: |
01001920DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.041 |
ABSTRACT
The growing demands of municipalities, industry, and agriculture for potable water have provoked a water deficit that threatens global energy, food, and economic security. Membrane separation processes offer promising low-energy solutions for desalination and wastewater treatment. However, the retention of solutes on the feed side of the membrane, known as concentration polarization, increases the pressures needed to force the fluid across the membrane surface. With time, the buildup of solutes forms a mineral scale that impedes filtration, damages the membrane, and increases maintenance costs. Many on-going research efforts are exploring both physical and chemical strategies to prevent scaling. One such strategy is to pattern a mesh-like net of physical spacers on the membrane that alters the fluid flow at the surface. This patterning creates complex fluid flow dynamics that are not well understood, particularly with the added complexity of solute filtration and the effect of concentration polarization. This CAREER project will develop a validated computational fluid dynamics model of concentration polarization and mineral scaling with patterned spacers for reverse osmosis and nanofiltration membranes systems.
This project will develop innovative computational fluid dynamics simulations that fully couple interactions between polarization, scaling, and mixing due to feed spacers. The simulations will address complications that arise due to both near-membrane mass transport and three-dimensional mixing due to the feed-spacers. The methods will be experimentally validated, and then used to: (1) develop improved models of polarization and scaling; (2) investigate the roles of spacers and operating conditions on system performance; and (3) explore the design of new spacers that minimize polarization and scaling. The project will directly train both graduate and undergraduates in conducting research, while also integrating the activities into undergraduate engineering design coursework. Outreach activities, in collaboration with a community center and Multicultural Engineering Program, will introduce both under-served middle and high-school students to computer programming, sustainable water issues, and STEM careers. The project is anticipated to accelerate informed design of membranes for extended lifetime and performance.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Reverse osmosis (RO) is a desalination technology with important applications to generating potable water from seawater and treating complex wastewaters generated by industry, agriculture, and municipalities. RO operates by flowing high-pressure water over a permeable material called a "membrane." The membrane acts as a sieve, through which water can pass while salts and other contaminates are removed. RO is a mature technology used extensively across the globe to treat a wide variety of waters. However, it is also an energy intensive process that can negatively impact energy and climate security. Furthermore, RO recovers only a fraction of the input water. The remaining wastewater has a high concentration of salts, and is challenging to dispose of safely and economically.
With these motivations, the objective of this research was to improve the energy efficiency and water recovery of RO systems. RO's energy efficiency and water recovery depend on complex fluid mixing that occurs as the water flows over the membranes. As this mixing is difficult to observe experimentally, this NSF project developed methods to simulate the mixing numerically. The methods addressed two major challenges. (1) The transport of water through the membrane requires unique numerical methods that are not available in commercial computer software. (2) The geometry of the flow channels within RO systems are complex, and require advanced methods to efficiently simulate. The numerical methods have been verified and disseminated to the public.
Using our numerical methods, we showed that fluid flow, energy efficiency, and water recovery in RO systems are strongly influenced by a plastic mesh that supports membranes within RO systems. As water flows through an RO system, the plastic mesh causes dissolved salts to accumulate at specific locations along the membrane surface. In these regions, the recovery of water is reduced, and the salts tend to precipitate and damage the membrane. By elucidating the physics of this accumulation process, we developed simple models that accurately predict the impact of supporting meshes, without requiring costly numerical simulation.
In addition to the fundamental research, this NSF project collaborated with a community center to provide campus visits to the Colorado School of Mines for historically underserved middle and high-school students from Aurora, Colorado. Students toured research labs, met with admissions counselors, and performed STEM experiments. The project also developed two open-source, graduate-level, textbooks in fluid mechanics and engineering mathematics. The project also incorporated 10+ undergraduate students who helped with laboratory experiments, numerical simulations, and data analysis.
Last Modified: 02/07/2024
Modified by: Nils Tilton
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