From The Editor | February 7, 2017

Changing Membranes And The Future Of Water

Peter Chawaga - editor

By Peter Chawaga

Changing Membranes And The Future Of Water

In an effort to advance membrane technology, the American Membrane Technology Association (AMTA), an industry advocate, and the U.S. Bureau of Reclamation (USBR), a federal agency that oversees water management, have awarded $11,750 fellowships to four graduate students around the country for the first time.

The White House Initiative on Water and Energy appropriated funds for research in innovative technologies and USBR was able to supplement those and allocate them for the fellowships, according to Harold Fravel, AMTA’s executive director. A longstanding partnership between the two organizations led AMTA and USBR to team up to select the beneficiaries.

“Each applicant submitted their resume, a letter of recommendation from their professor, and a detailed description of their research and how the funds were going to be used,” said Fravel. “The applications were ranked independently by AMTA and USBR and from there the four fellowship winners were selected.”

Each student chosen for the fellowship is working on a project that meets USBR’s objectives for reducing costs and environmental impact of water treatment for augmenting water supplies and AMTA’s goals to promote and advance membrane technology.

“If the goal is to reduce cost, reduce energy, and reduce environmental impact, the investment needs to be made on the membrane side of these technologies and innovative new ways of using different materials to make membranes is where a lot of the research is still needed,” said Yuliana Porras-Mendoza, USBR’s research coordinator for advanced water treatment. “Augmentation of clean water supplies is crucial and funding research such as the projects AMTA and USBR have identified for this first year of fellowships is the first step.”

Fravel, who regularly witnesses the advancement of membranes for water treatment in his role with AMTA, believes these projects demonstrate the limitless future the technology has.

“Although the technology has been adopted widely, there are improvements that can be made to make their use even more economic by lowering energy demands, reducing fouling, and even improving separation,” he said. “As the sources for water become more demanding, traditional water treatment may not be able to do the job and an alternative technology must be used. Membranes can fill that void.”

Working On The Future

Masoud Aghajani of the University of Colorado, Boulder, is a second-year doctoral student studying fabrication and characterization of patterned thin-film composite membranes, which have controlled surface patterns that can reduce concentration polarization, fouling, and scaling.

“This work has been done with ultrafiltration membranes and demonstrated improved resistance to fouling,” said Fravel. “If the same technology can be applied to thin film composite membranes for reverse osmosis, it could be of great importance by reducing fouling and improving water quality in the permeate.”

Aghajani’s work may also come to benefit the planet.

“This could also reduce the use of chemicals to clean membranes, which would have a positive environmental impact,” said Porras-Mendoza. “If we can reduce fouling and scaling, then the membranes would require less energy as well.”

Kasia Grzebk, a third-year doctoral student at the University of North Carolina at Chapel Hill, is working on incorporating zeolites into thin-film nanocomposite membranes, which could allow for water reuse.

“To date, most of the work done with similar products has been for the standard feedwaters,” said Fravel. “Any reduction in energy and improvement for water reuse applications will be important.”

That potential for reuse is directly in line with USBR’s hopes for the future of how membranes are utilized.

“Improved membranes for the water reuse industry will help continue the work of finding solutions to augment water supplies, not only for potable use, but also for other uses such as agricultural irrigation, industrial use, and groundwater recharge,” said Porras-Mendoza.

Carlyn Higgins, who is working towards her master’s degree at the University of Central Florida, is modifying a nanofiltration membrane process for acid pretreatment conditions, trying to model mass transfer and endocrine-disrupting compound removal. The research is part of the university’s effort to investigate acid reduction options for the nanofiltration system at Jupiter, FL’s central port. Hopefully, it will provide a potential design to help engineers with similar scenarios in the future.

“This research is important for understanding how these very complex compounds react to membrane treatment and mass transfer modeling is the first step to having a scientific understanding,” Porras-Mendoza said.

Chris Morrow, a third-year doctoral student at the University of Southern California, is studying low-energy potable reuse through osmotic membrane bioreactors coupled to membrane distillation. His work couples two waste products, waste heat and wastewater, to produce a drinking water quality product with minimal external energy supply.

"We are seeing increased water stress all over the world, particularly in urban areas, and wastewater reuse has the potential to fill the gap," Morrow said. "This research is important because it provides a low-energy alternative to conventional wastewater reuse that is energy intensive. This technology has the potential to not only increases domestic water supply, but also to protect the environment by decreasing water withdrawals."

Coming To A Plant Near You?

As for when treatment plants will be able to get their hands on this technology, Fravel is optimistic that they could all be commercialized within a few years. Particularly, he thinks Higgins’ and Grzebyk’s work could be applied quickly.

Porras-Mendoza, however, notes that the road could still have some obstacles.

“This is still very early research at the laboratory scale and research like this takes years before it can become commercial,” she said. “Funding is also key to ensure that this work moves from the laboratory scale to pilot scale to demonstration and finally commercialization. A lot of what this work can provide is early answers to what does not work, so others don’t spend time on what doesn’t work and fix what can be fixed.”

If the students really are on the verge of the latest breakthroughs, their work will find treatment plants sooner or later.

Image credit: "scientist working at the laboratory," BRITICO © 2009, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/