ACR Special Issue: Water for Two Worlds: Urban and Rural Communities

Special Issue in Accounts of Chemical Research Lead by Westerhoff, Boyer, Linden 2019

Supplying clean water and sanitation are major accomplishments of the 20th century, but growing populations, aging infrastructure, and changing water quality challenges place new stresses on water in both affluent and developing countries. Within rapidly growing smart and connected megacities, there are opportunities to reuse water and use water infrastructure to recover critical elements and even electrical power, and these will be enabled through interconnected cyber–physical treatment systems. New materials and technologies are also enabling smaller, modular, and inexpensive systems that purify water. There is an emerging recognition that different technologies are needed for and within cities and rural populations, and one technology cannot simply be scaled up or down in size to meet all needs because of the complex biogeochemistry within waters. This special issue, guest-edited by experts in the field Paul Westerhoff and Treavor Boyer (Arizona State University) and Karl Linden (University of Colorado, Boulder), presents examples of the diverse challenges in this field and approaches to improving drinking and waste water purification or recycling.

Two Pod-Casts by Westerhoff for NNCO

(March 22, 2018)  World Water Day is an annual event celebrated on March 22nd. The day focuses attention on the importance of universal access to clean water, sanitation, and hygiene facilities in developing countries. The National Nanotechnology Coordination Office (NNCO) is celebrating this year’s World Water Day by releasing a series of videos and podcasts, and by highlighting the U.S. National Nanotechnology Initiative (NNI) Nanotechnology Signature Initiative (NSI) on Water Sustainability—and the role of nanotechnology in providing clean and affordable water solutions.

Podcasts: As part of the NNCO’s ongoing series, two podcasts will be released for World Water Day. One podcast features Arizona State University’s Paul Westerhoff discussing the bold new research efforts at the Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment Nano-Enabled Water Treatment (NEWT).

The Second pod-case is at :

NNI Podcast by Westerhoff: A NEWT, a Nanoparticle, and an Engineer Walk into a Lab: Using Nanotech to Purify Water

A NEWT, a Nanoparticle, and an Engineer Walk into a Lab: Using Nanotech to Purify Water

For World Water Day, Dr. Paul Westerhoff discusses using nanotechnology to purify, polish, and remove pollutants from water. He also talks about bringing clean water to places that are off the water grid.

Follow link here:

Our paper was including the Nature Geoscience Focused issue on “Inland waters under threat”

ature Geoscience has just been published and features a bunch of great papers and opinion pieces about inland aquatic systems. We’ve taken the opportunity to put together a special focus collection on inland waters, their many contributions to ecosystems and biogeochemical cycles, and the challenges they face due to climate change and human actions.

High levels of endocrine pollutants in US streams during low flow due to insufficient wastewater dilution

Cool YouTube Videos developed by our students

Click here to find more

Nanosystems Engineering Research Center (NEWT)

Videos created by members of the NSF funded Nanotechnology-Enabled Water Treatment (NEWT) Engineering Research Center – a collaboration between Rice University, Arizona State University, Yale University, and the University of Texas El Paso.

notechnology limit biofouling in water treatment?

How silver nanoparticles can help reduce biofouling in water filters

How silver nanoparticles can help reduce biofouling in water filters

How silver nanoparticles can help reduce biofouling in water filters

How silver nanoparticles can help reduce biofouling in water filters?




Portrait of Paul Westerhoff with a caption of His ideas are transformational . . . and he's never satisfied with small, incremental advances in knowledge,” says a colleague of new ASU Regent’s Professor Paul Westerhoff. “Because of his persistence and dedication, Paul's work will always be on the cutting edge." Photographer: Jessica Hochreiter.

Paul Westerhoff figures he was “destined to be an engineer.” But that is mostly because while growing up, he jokes, “I just didn’t know anything else existed.”

His father was an environmental engineer. One of his two older brothers became an electrical engineer, the other a mechanical engineer. It just seemed natural for him to follow in the family footsteps.

Still, Westerhoff took his time in college before declaring a major. The only thing he was decided on was that “I wanted to do work involved with things outside.”

He liked the outdoors and gravitated toward “doing things around water,” specifically lakes, streams and rivers.

It was a course in hydrology — the study of water in the environment —that finally fixed him onto a specific educational track.

“It was the first time I had a class that really integrated my interests in mathematics, statistics and technology, and the teacher talked about how all that could relate to rivers,” Westerhoff recalls. “Everything just came together for me at that point.”


The water thing has worked out well for him. Westerhoff, a professor of civil, environmental and sustainable engineering in Arizona State University’s Ira A. Fulton Schools of Engineering, is today a well-recognized leader in water treatment and water safety research.

He has received many of the most highly regarded awards for his work in the field, and his more than 200 peer-reviewed journal publications have made him among the most highly cited researchers in environment and ecology studies.

He directs a U.S. Environmental Protection Agency research network that teams nine universities to study the lifecycles of nanomaterials and their impacts on the environment and human health.

He is deputy director of the National Science Foundation Engineering Research Center on Nanotechnology Enabled Water Treatment. The center is developing technologies to provide clean water to millions of people in areas throughout the United States that still lack it.


During his 22 years at ASU, he has also received accolades for his skills as a teacher, mentor and administrator.

Westerhoff has garnered awards for his work mentoring doctoral students and teaching undergraduates, and has been instrumental in helping to establish the Fulton Schools’ graduate and undergraduate degree programs in environmental engineering.

He has also served at various times as a civil and environmental department chair, the founding director of the School of Sustainable Engineering and the Built Environment, the Fulton Schools Associate Dean for Research, the ASU Vice Provost for Academic Research Programming, and Senior Advisor on Science and Engineering to the ASU Provost.

In 2016 the Fulton Schools created a new position and he was named the interim Vice Dean of Research and Innovation.

Why take on the extra administrative tasks on top of his research and teaching?

“I just get bored,” he says,” “and I need to be intellectually challenged.”


With or without boredom as motivation, Westerhoff’s range of achievements has now earned him designation as a Regents’ Professor, the highest honor bestowed on faculty members at Arizona’s three state universities.

The title recognizes accomplishments in research, education, scholarship, creative endeavors and public service that have brought national and international distinction.

Colleagues attest to the widespread impact of Westerhoff’s contributions.

“His research is highly relevant to society because insufficient access to clean water is a major limiting factor to human capacity,” says Pedro J. Alvarez, the George R. Brown Professor of Civil and Environmental Engineering at Rice University and director of the Nanotechnology Enabled Water Treatment research center.

“Paul excels in scientific rigor. He does a great job of bridging the interface between the discovery-driven culture of science and the innovation-driven culture of engineering,” Alvarez adds. “It’s rare to find someone with such depth and breadth in issues related to water treatment.”

Menachem Elimelech, the Roberto Goizueta Professor at Yale University, points in particular to Westerhoff’s essential work exploring the environmental implications and applications of engineering nanomaterials as only one of his “numerous important contributions to the field of environmental engineering.”

University of Colorado Boulder Professor of Environmental Engineering R. Scott Summers sums up, “There are only a few who are able to visualize solutions to major challenges, and fewer still who can clearly articulate those solutions. Paul has that gift.”

“Paul’s research is never ordinary,” says Clemson University’s Vice President of Research Tanju Karanfil. “He’s always looking for solutions to environmental problems that are out of the box, and he’s never satisfied with small, incremental advances in knowledge. His ideas are transformational, which is exactly what our field needs. Because of his persistence and dedication, Paul’s work will always be on the cutting edge.”


Westerhoff doesn’t view his new Regents’ Professor status as a platform for shining a spotlight on career success. He hopes only that it might in some way boost his ability to make further impacts in the professional endeavors he cares about most.

In his new vice dean position, he wants to foster a stronger innovation mindset among the Fulton Schools’ 300-plus tenure-track faculty.

That involves them zeroing in more directly on use-inspired research pursuits with entrepreneurial potential.

“It’s the idea that progress isn’t just publishing in research journals, but in getting patents or starting a company,” he explains. “That might mean focusing on producing results that could have important concrete benefits rather than just finding out more about something that is merely interesting.”

“Paul is very creative and has a tremendous skill for identifying timely, relevant and interesting challenges,” says Julie Beth Zimmerman, an associate professor of chemical and environmental engineering at Yale University. “Not only is he adept at getting others to join the cause, he has a powerful gift in bringing out the best in those individuals, and even more importantly, realizing outcomes greater than the sum of the individual collaborators.”

Westerhoff is leading by example on the entrepreneurship front. He and his wife, Kelly, also an engineer (they met in graduate school), are forming a start-up that would license some of the water-treatment technologies he has developed and move them toward commercialization.

“I am manager and technical advisor,” he says. “She is the company president.”


He also wants to continue using his expertise to help communities through his work as a member of an EPA science advisory board, as well as with the information and advice he has been providing to local governments and public groups that have been regularly seeking his consultation for more than a decade.

He has been participating in efforts to find water treatment, safety and pollution solutions for a number of sizable municipalities and urban regions, including Los Angeles, as well as for rural agricultural and ranching areas.

“It’s really interesting to help bring science and engineering experience into the mix of making public policy, and to see it come together toward something positive,” he says.


With all of this multifaceted work on his agenda, Westerhoff still keeps teaching and mentorship high among his priorities.

He says one of best rewards of his job is watching the young undergraduates he teaches transition “from looking clueless and confused to starting to figure things out, to finally mastering complex concepts and ideas.”

With the advanced students, he likes pushing them to excel beyond the classroom — urging them to compete for scholarships, learn how to pitch themselves to employers, map out their career-planning strategies and develop their own research pursuits and their own creative approaches to problem solving.

Westerhoff’s measure of success in his role as an educator and research director is a simple one: “It’s when I’m learning as much from the students as they’re learning from me.”


ASU nanoparticle expert uses research to move society past fear

Read more

February 14, 2017

Newly named Regents’ Professor Paul Westerhoff is part of an initiative to harness the tiny specs to purify water

When people find out there are invisible particles in their food or water, they become alarmed.

Arizona State University professor Paul Westerhoff has dedicated his career to producing research that answers people’s questions and moves them past fear.

“The things I do are not from a scare-mongering point of view, but trying to answer objective engineering questions,” said Westerhoff, a professor of in the School of Sustainable Engineering and the Built Environment at ASU.

Westerhoff, an environmental engineer, has been named one of three Regents’ Professors for the 2016-2017 academic year. Regents’ Professor is the highest faculty honor and is conferred on full professors who have made remarkable achievements that have brought them national attention and international distinction.

An expert in nanoparticles, Westerhoff started working on the tiny specks even before they had a name. As a graduate student, he worked on water filtration.

“At that time we talked about these things called ‘sub-micron particles,’ which we couldn’t measure very well but we did a bunch of experiments with them anyway,” he said.

A few years later, when the term “nano” was becoming popular, he realized he had already done it.

“So I put in my first proposal, and it got funded because I was one of the first people who had data!”

Now, he focuses on using nanoparticles to treat and purify water, an interest that was piqued by a hydrology class he took as an undergraduate.

“I understand water,” he said. “I like fishing and swimming and kayaking, and I can go to a river and not only understand the hydrology. But I know why the water is a certain color. And I know where it came from. And I know all the fish that live in it.”

From his first studies, he saw the trajectory of public perception about invisible and unknown substances in the environment, and how that could influence his research.

“In the environmental world, initially it’s like the world’s going to end. But what I’ve learned is that these things move through predictable trends,” he said, using as an example “Silent Spring,” a 1962 book by conservationist Rachel Carson that documented the effects of the use of pesticides, including DDT.

“It’s in this early stage that people are scared, while the agriculture industry and pesticide industry responded by saying that they save millions of lives. In the first few years there’s a lot of uncertainty,” he said.

“Then researchers come along and help reduce that uncertainty.

“Then there’s another phase where politics come in, and there are cost decisions and people think about regulations and finding alternatives,” he said.

“We still find DDT in the environment, but it’s regulated and people really aren’t scared of it. It’s like a 20-year cycle.”

Westerhoff said the key is to know which phase is coming next.

“As a researcher you want to be focusing on what will be the important question to answer in three to five years, before people even know it’s a question,” he said.

“In nano, we were ahead of the game in thinking, ‘Maybe this isn’t so bad, maybe we can use it.’”

Now he’s deputy director of the Nanotechnology Enabled Water Treatment Systems Center, which is focused on developing compact, mobile, off-grid systems that can provide clean water to millions of people who lack it.

Many of Westerhoff’s research projects have been funded by agencies such as the National Science Foundation and the Environmental Protection Agency, but he also works with water utilities, non-governmental organizations and industry partners.

“Industry wants to know the answers to things. It’s moved out of the scientific ‘what if’ toward reality,” he said. “They all have agendas and as long as you understand their agendas, they ask interesting questions.”

“As a researcher you want to be focusing on what will be the important question to answer in three to five years, before people even know it’s a question.”

— Regents’ Professor Paul Westerhoff

Westerhoff was commissioned by the environmental activist group Friends of the Earth to see whether there were nanoparticles in powdered infant formula after the manufacturer declined to reveal whether there were.

His lab found needle-shaped nanoparticles in the formula.

“In Europe, there’s a warning on their use in cosmetics but yet they’re in infant formula,” he said.

They discovered the nanoparticles did not dissolve in either water or saliva, but when they put them in stomach fluid, they dissolved instantly.

“They did it to deliver calcium to the gut very efficiently, so they didn’t have to use as much,” he said of the manufacturer. Friends of Earth was concerned that the formula labels didn’t disclose the presences of nanoparticles.

“That’s an example of where one group sees something as a risk to society but a company sees it as a benefit.”

He’s also seen the evolution of how scientific research is portrayed in the media. In 2008, he supervised a doctoral student on a research project that studied the use of nanosilver in socks to eliminate stinky feet. They wanted to know: Did the particles wash out of the socks and into the water supply? The answer was yes.

Journalists jumped all over the story. One headline read, “Toxic socks?”

“We kept telling them the amount of silver is very small and won’t affect anything. None of them got it, and everything they wrote was over the top,” Westerhoff said. “They don’t want to hear that ‘everything is safe, there’s no problem.’ They want to hear ‘there’s nanoparticles in donuts.’ “

In 2015, Westerhoff was named an Outstanding Doctoral Mentor by ASU’s Graduate College. His former students said he is able to deftly balance the guidance that students crave with the independence they need to cultivate.

Troy Benn, who worked with Westerhoff on the nanosilver paper and is now an engineer in Montana, said: “For a young kid it was a little bit shocking because you do all your research in a lab and you don’t talk to anyone outside, and all of a sudden people are asking you what you did.

“Paul’s good at knowing how much guidance each student needs because they’re all unique.”

Kyle Doudrick, who was a graduate student at ASU from 2008 to 2013, said that even with the enormous workload of a full professor, including travel, plus the administrative duties of a vice provost, Westerhoff found time to meet weekly with the students he advised.

“It was a good balance of managing but also letting you find yourself in your independence but not so hands off that you had no idea what’s going on,” said Doudrick, who is now an assistant professor in the Department of Civil and Environmental Engineering and Earth Sciences at the University of Notre Dame.

“The research I did was on nitrate as a contaminant in water,” he said. “He wasn’t the expert but what he was good at was making the student the expert, and that’s the whole purpose of the PhD, is to become an expert at something.”

Even now, Westerhoff teaches ASU 101, the required, one-credit course that all first-time freshmen take.

“I ask them why they want to be engineers, and about half have a life story of something they want to solve. They have a deep passion.

“And if you don’t hear that until you see them in grad school, you’ve lost touch with what motivates people.”

Top photo: Newly named Regents’ Professor Paul Westerhoff spends part of every week supervising students in the hydrology lab where his students work in ISTB4. Photo by Anya Magnuson/ASU Now

Mary Beth Faller

Mary Beth Faller

reporter , ASU Now