If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



Podcast: Jessica Ray and William Tarpeh on clean water, turning trash into treasure, and life as assistant professors

These environmental engineers tell Stereo Chemistry about their visions for the future of our water . . . and share some laughs along the way

by Katherine Bourzac , Kerri Jansen
December 21, 2021

Graphic shows half-tone headshots of Jessica Ray and William Tarpeh next to the words In conversation with Jessica Ray and William Tarpeh and the Stereo Chemistry podcast logo.
Credit: Will Ludwig/C&EN/University of Washington/Courtesy of William Tarpeh
Credit: C&EN

How do we build water systems that are sustainable and also equitable? On this episode of Stereo Chemistry, Jessica Ray and William Tarpeh talk with C&EN reporter Katherine Bourzac about how they use their chemical engineering know-how to develop simple systems for filtering toxic chemicals from our water and harvesting useful chemicals from urine. They also discuss finding ways to thrive as assistant professors and building support networks as Black junior faculty.

Sign up for C&EN’s weekly newsletter at

Subscribe to Stereo Chemistry now on Apple Podcasts, Spotify, or wherever you get your podcasts.

The following is a transcript of the episode. Interviews have been edited for length and clarity.

Jessica Ray: Are there urine jokes? I still hope you have the urine jokes. That’s what kept me going.

William Tarpeh: Oh, like “Think about the pee-tential from what you can do!” I didn’t know we were going there today Jess.

Kerri Jansen: You’re hearing Jessica Ray and William Tarpeh reminisce about their time working at UC Berkeley. They’re both environmental engineers who specialize in water treatment and wastewater. For Will, that wastewater happens to be urine. We’ll hear more about that later. I’m Kerri Jansen.

Attabey Rodríguez Benítez: And I’m Attabey Rodríguez Benítez.

Kerri: On this episode of Stereo Chemistry, we’ll hear Will and Jess talk about how they thrive as assistant professors.

Attabey: We’ll also explore the science of clean water and the visions Jess and Will have for a more sustainable future.

Kerri: For these two engineers, that means much more than just developing green technologies. They want to make sure everyone has access to clean water and sanitation. Jess and Will discussed those goals and more in a recent chat with C&EN reporter Katie Bourzac. Welcome to the show, Katie.

Katherine Bourzac: Hi, thanks for having me on the podcast!

Kerri: Well, I’m excited to hear more from Jess and Will. Katie and Attabey, I’ll let the two of you take it away.

Attabey: Thanks, Kerri. So Katie, I was really interested to hear more from these two about how they’re navigating life as new professors. They both started their own research labs within the last few years, right?

Katie: Yeah, that’s right. Jess’s lab is at the University of Washington in Seattle. Will is at Stanford University. Now that they’re both assistant professors, they’re helping each other figure out how to thrive in this relatively new role. As Will noted, being a new professor can result in some tricky situations.

William Tarpeh: OK, assistant professors, we get a lot of advice. And that’s a great thing from mentors. And sometimes, honestly, you get conflicting advice. And you’re like, OK, what do I, how do I navigate these two pieces of completely diametrically opposed advice?

Attabey: I can sure relate to that—I had two professors as my main advisers when I was in grad school, and let me tell you, it was an adventure. Figuring out how to navigate all voices and opinions took a lot of communication and patience!

Jess and Will told us that a big part of how they deal with conflicting advice and other challenges is by supporting each other. They’re both part of multiple support networks—mostly online over the past few years, due to the pandemic. They told us they meet regularly on Zoom with a group of other Black assistant professors to work on grants and papers they’re writing. And they give each other advice.

Jessica Ray: Yeah, it’s a great space. I think what I also benefit from is the peer mentoring, because we’re all at slightly different stages. We’re all, you know, assistant professors, but all at slightly different stages. So I get a lot of great info about issues that I’m having as an assistant professor. And then we also give back to the newer recruits that join the writing group as well. So it’s been really nice.

William Tarpeh: Yeah, share proposal drafts, edit each other’s work as needed, that type of stuff. Also troubleshoot, like, how do I talk to my department about this? Or how do I work through this with a student, that type of stuff.

Attabey: Having the writing group opens the door to other conversations and other forms of connection.

Jessica Ray: During the pandemic, as we continued our writing time, we were, in addition to providing peer mentoring, just talking about frustrations that we have observed as Black faculty in our various departments. Usually, we’re the only Black faculty within our department, sometimes one of maybe two or three in the whole college of engineering or school of engineering.

William Tarpeh: So we have just started an assistant email thread, but there are 15 or 20 of us. And that, in and of itself is very encouraging, as Black faculty members, to say, oh, wow, there’s a lot of people replying to this email, getting added, everyone is just adding people. And it’s like, if you asked me how many Black faculty members are there in my field, I would have underestimated. And so that in and of itself is efficacy building, helps increase the awareness.

There’s also kind of unique needs that Black junior faculty may have in addition to those of every junior faculty member. And also that means that helping and building an environment in which Black junior faculty can thrive, of course, has spillover effects. If we’re doing things like making evaluation metrics clear, or if we’re doing things like establishing mentoring committees, everyone benefits from that.

Attabey: And having a group of peers where you can bring your whole self to being a scientist can also mitigate the effect of stereotypes. Will talked about how stereotypes can mess with your head.

William Tarpeh: The idea being if you’re aware that there’s a stereotype in some setting where you are, it adds extra mental load, and it may affect your performance in that setting, right? Whether it’s being a Black student in a math class, or taking the SAT, and you’re made aware when you fill out the Black/African American bubble, that, oh, there’s a stereotype that Black people aren’t good at math, that might affect your performance.

Attabey: And for Will, support from peers and senior mentors can deflate the power of stereotypes. Jess added that role models are also important too, especially for Black students.

Jessica Ray: If you talk to most graduate students, for example, who are Black and interested in pursuing, you know, PhD research or becoming faculty, something that echoes in a lot of their comments is the ability to see faculty that look like them to be represented in their future department, to see someone that looks like them.

Attabey: Yeah; finding a community of people with a similar background is really how I got through grad school—just having a space where I could be my authentic self. So that makes me curious . . . how did Jess and Will meet? Will was a grad student, right?

Katie: Yeah, that’s right. Will was a grad student at UC Berkeley, and Jess was doing a postdoc. Let’s hear the story.

William Tarpeh: In 2015, Jess just walked into the Berkeley Water Center and walked right by my desk, because I had the honor of having the front desk in the whole place right next to the locked door, which meant I got a lot of exercise jumping up and down when people would knock. And Jess just walked by, and I was like, oh, who’s that? And so then we met, probably later that week. We weren’t in the same research group, but we were in closely tied research groups; we all shared lab space.

Jessica Ray: When Will was a PhD student, he was conducting research on urine source separation, which you should also ask him about, it’s really interesting. And for his urine source separation research, he, of course, needs urine to do the experiments. And I was a very proud donor to Will’s PhD research. So . . .

William Tarpeh: Thank you, thank you.

Jessica Ray: . . . when you get your multimillion dollar award, I want acknowledgement for my contributions. I mean, that is one vivid memory I have of our time at Berkeley. Like oh, Will’s collecting urine again, I guess it’s time!

Katie (in interview): And that’s because you’re trying to collect some nitrogen or . . .?

William Tarpeh: Good question Katie. Why are we doing this? Yeah, so, we were . . . at the time when I was a PhD student, we were developing some novel technologies to selectively recover nitrogen as ammonia from urine. Why urine? Because urine is just 1% of wastewater volume, but contains a large portion, around 80%, of the nitrogen that we excrete.

Katie: Will, is it challenging for you to solicit samples from people, or does your work still involve this?

William Tarpeh: It does, but now we have a whole operation. It’s amazing.

Katie (voice-over): Will’s lab has what they call a dispensing room.

William Tarpeh: The crown jewel of our lab.

Katie: Basically, it’s a few lab-grade urinals that capture people’s pee. There’s also a setup to discreetly urinate into a sterile cup. Will has decorated the area with humorous and encouraging slogans to capture the interest of his donors—you heard some examples of those at the beginning of the episode.

William Tarpeh: Like “Urine luck! Today’s your day to donate.” These are the things I would put above the collection containers just to catch people’s eye.

Attabey: OK, but why all this talk about urine? Katie, tell us a little bit more about Jess and Will’s research.

Katie: Right, so, as we mentioned earlier, Jess and Will are both environmental engineers who work on water. Jess uses her knowledge of chemical engineering and nanotechnology to make new materials for water treatment. Her goal is to make equal access to clean water a reality. So she’s developing low-cost systems for removing toxic chemicals from our water.

And many of Will’s projects are about sanitation and how to treat wastewater. That means developing low-cost systems that clean up waste for schools around the world. He’s also interested in mining valuable chemicals from our urine. Our pee has ammonia in it that Will thinks we could capture and use as a low-cost fertilizer.

Attabey: And Will’s work goes way beyond just nitrogen. His vision is to mine different types of wastewater for a range of valuable materials.

William Tarpeh: Humans, we generate teraliters of wastewater every day. It’s kind of a huge mind-boggling number. And that’s even hard to wrap your mind around, but it’s a lot of wastewater. We’re extracting and consuming materials from the environment and then just emitting them into the environment in different forms. And that, by definition, is an unsustainable system.

Attabey: Will wants to mine nitrogen, phosphorus, and even carbon that could be used for fuels. Mining chemicals from wastewater, in the process of cleaning it up, has a double benefit. In the end, you get clean water and valuable chemicals.

William Tarpeh: There’s literally so many minable products in wastewater that a lot of us will be in business for decades, because there’s still more you can extract from wastewater. And it solves two problems at once, right?

Katie: And Jess is also making good use out of something that usually gets thrown away. She’s not working with urine, but she is turning trash into treasure.

Jessica Ray: So one of the materials that our group is developing is taking used coffee grounds that we’re actually getting from the University of Washington catering services after their events. And then we burn those in the lab and create an activated carbon adsorbent that we’re then testing in the lab to remove stormwater contaminants. So it’s a really nice puzzle of, you know, the two things you think about when you think of Seattle: you think of the coffee capital of the world, and you think of all the rain that we get. So it’s a nice marriage of the two, and it’s another example of how we can upcycle what otherwise would have been just a composted waste and then using that for an environmental good.


Katie: Jess’s materials can filter out contaminants that are harmful to people and to animals. For example, her team is targeting a class of contaminants that we often refer to as PFAS. That stands for a kind of intimidating chemical name that I will say once, and never again in this episode: they are per- and polyfluoroalkinated substances.

Attabey: That’s quite a mouthful. But PFAS are pretty common, right?

Katie: Yeah, that’s right. These chemicals are in a surprising number of products you probably have in your home right now, like nonstick pans and waterproof coatings on takeout food packaging. They’re also used as fire retardants. Unfortunately, some kinds of PFAS are toxic. They’ve been linked to immune system problems, cancer, and other health issues.

Attabey: And these compounds earned the nickname “forever chemicals” because they are super stable. And that’s a good thing if they’re being used on something like a nonstick pan, but it also means they persist in the environment for a really long time.

Jessica Ray: Because of all these uses and developments and applications, there are now over 5,000 different types of PFAS within the class of compounds. And this is a problem because of the way they’re designed, right? So we need to come up with more creative and innovative approaches to first remove those compounds from water and then ultimately degrade them so that they no longer pose a risk to human and environmental health.

Attabey: With Will trying to mine wastewater for resources and Jess making used coffee grounds into water filters, it sounds like they are focused on recycling and sustainability.

Katie: Yeah. They’re both passionate about chemical solutions that eliminate waste, rather than generating more of it. And that ultimate goal has naturally led Will beyond water to other kinds of waste recovery. For example, here is how Will thinks about a topic his lab has started to investigate recently—engineering new polymers.

William Tarpeh: When we think about just the kind of heaps of plastic when you take out your recycling bin every week . . . and you think about, you have filled this bin that is several gallons large, and you look at all the houses on your street or all the apartments in your complex, and you start to get a sense of the scale of that, right? And it kind of makes you wonder when people were designing these plastics, in the 20th century in particular, it’s like, were they thinking of the scale of what happens during disposal? And I think they were thinking of the scale in terms of getting plastics in people’s hands and making these convenient, right? It’s not like . . . sometimes I try to remind my students, it’s not like people who came up with these things were like evil people, right? It’s just like the world was different, constraints were different, incentives were different, right? It was like about democratizing things and getting lots of people access to things.

Katie: But that mindset doesn’t take into account what happens when you throw plastic away. Will told us he’s really excited about the opportunity to rethink how products are designed, down to the base polymers that are used to make them. That way, they can be safer to dispose of once they’ve reached the end of their useful life.

William Tarpeh: Right, so now that we think about disposal a lot, it means that if we think about designing with the end of life in mind at the beginning, it’s going to change which polymers, or which formulations, we think are best suited for different applications, right? And so it takes this whole reframing of one’s mind to really change and forecast for decades. And that can be paralyzing at times but it also, like, gives you a felt sense of opportunity.

Katie: So that was really big-picture. We’ve been talking about how to make a circular economy, where water and polymers and other precious resources get reused, not wasted. Next, we’ll zoom in a little on how Jess and Will want to accomplish this. Knowing that these two are friends, I wanted to know if they had any questions for each other. We’ll hear more about that after a quick break.

Gina Vitale: Hi everyone, Gina Vitale here. I’m an assistant editor at C&EN. And I’m here to remind you about a great way to stay up to date with the latest news from the world of chemistry and chemical engineering: our weekly newsletter.

The newsletter delivers the best of C&EN to your inbox every week. You’ll get the most important research findings, the emerging trends you need to know to get ahead, plus the latest jobs and career insights. And also some really cool extra content, like Periodic Graphics in collaboration with the science illustration website Compound Interest. Or Chemistry in Pictures, which showcases the beauty of the central science.

You can sign up for our newsletter at Just point us to your inbox, and we’ll take it from there.

Again, that link is And now, back to the show.

Attabey: So before the break, we heard about Jess and Will’s focus on sustainability. In the second half of the show, we’ll hear more about how they’re putting this green vision into action.

Katie: That’s right. When I asked them if they had any questions for each other, they both wanted to pick each other’s brains about opportunities for more sustainable water systems. And being engineers, they got right to the nitty gritty of it.

Katie (in interview): So I had asked you guys, if you wanted to, like, ask each other any questions in this forum? Give you some time to do that.

Jessica Ray: I have a question for Will.

William Tarpeh: That was fast. OK.

Jessica Ray: So, my question is: What, in your opinion, is the biggest opportunity in, like, source separations, or electrochemical separations?

William Tarpeh: Ooh, in electrochemical separations, biggest opportunity. How much time you got, Jess?

Jessica Ray: I figured you might have something to say.

William Tarpeh: I think I’ll interpret the question, though, to think about the kind of fundamental advances that electrochemistry could afford. And I think, one that I’ve been thinking a lot about, and many people have been, as well, is kind of combining electrochemical separations, with electrochemically driven reactions. The idea being that codesigning catalysis and separations using electricity as a driving force for both can really change and enable—maybe more importantly, it can enable—completely new applications.

Katie: It seems Will is always thinking about new ways to turn wastewater into treasure. Jess’s answer to Will’s question hits a little closer to home. She pointed out a surprising feature of the water we use.

William Tarpeh: I think I would throw it back at you Jess, I want to hear more about stormwater. I feel like I haven’t heard you talk about stormwater for a long time. Maybe it’s a climate change question. But, like, what do you think are like the opportunities we’re missing in stormwater treatment, like the overlooked things?

Jessica Ray: Something I talk about is how, for example, all of the water in our toilets is drinking water quality, and the water that we use to water our lawns in front of our homes, and at parks and playgrounds, that’s all, you know, drinking water quality water that we have treated to the highest extent possible. And if we can think more creatively about other water sources to use to save drinking water for drinking, and not to use for these existing applications, then we can really think more creatively about how we manage our existing stormwater. Because right now, we don’t. In most newer US cities, when it rains, the stormwater goes down a drain and then directly into the nearby lake or river.

Katie: That’s pretty wild to think about. Does the water we use to flush our toilets really need to be as pure as the water coming out of the kitchen tap?

Attabey: If you’re fortunate enough to have a reliable, clean water supply, it can be easy to take that for granted. You just turn on the tap, or the hose, and it’s there. But that’s not the case for a lot of people. There are many reasons why someone might not have access to a safe water supply, including rising costs, inadequate infrastructure, contamination in water systems, or environmental reasons. I grew up in Puerto Rico, where we sometimes have droughts in the summer. And during one of those droughts when I was in college, 24 of us in a dorm had to ration a water drum. It was a challenge, to say the least!


Katie: I can imagine! These kinds of experiences can really affect your point of view. I live in drought-prone California, and I grew up here. Growing up, our family was on well water. My parents were always reminding my brother and me to turn off the tap, and we had to take short showers. Now that California is in another historic drought, I think about water conservation every day. Climate change is making droughts more frequent and more severe. That’s why scientists like Jess and Will are working on ways to conserve water as much as possible—not just in the lab, but at home, too.

Katie (in interview): So for you guys thinking about water all day, every day, does that influence, you know, what you do in your home? Do you do anything to save water?

Jessica Ray: I will say, at times, especially with respect to the vast amount of contaminants present in water sources, and understanding the level of efficacy of existing water and wastewater treatment plants, it can be really concerning to know what’s there, and what’s not being done. I do like to inform, you know, friends and loved ones about perhaps changing some practices that will help mitigate what I already know to be a significant problem. So, you know, we all have people in our lives like that. And sometimes it can be really great and really inspiring. And sometimes it can be really annoying. So, walking that fine line of, like, “here’s what I know, that you might be interested in,” is difficult to balance sometimes. But yes, absolutely. I try to save water as much as I can.

William Tarpeh: Definitely, I think Jess has covered it in terms of water. I feel like in my family and circles of friends, I am not the environmentalist, but I certainly am on that side of the spectrum. So we compost at home, because I like doing that. And I, like many people, have a pandemic garden of which I’m very proud. And yeah, we compost, and I’m trying to convince my wife to let us install a source-separating toilet. That’s sort of like a long game. Jess knows my wife’s issues. It’s a step-by-step thing. But like, we’re making progress, I think we can confidently say.

Katie (voice-0ver): Those are some good thoughts on what we can do to be green at home and conserve water. But I also wanted to know what these engineers see as the future of water on a larger scale. Our individual decisions are important, but as we all know, it’s about a lot more than that. Jess said her number one concern is not a purely scientific one. She wants to make sure all people have equal access to clean water.

Jessica Ray: I think first is equitable access to clean drinking water throughout the US and making sure that we don’t continue propagating existing disparities with respect to not only clean access to water, but just environmental pollution in general, making sure that we protect the communities that are most vulnerable.

One of my first projects was building or designing iron oxide nanoparticles to treat arsenic in water. And so when I was doing some research about arsenic contamination, I found a lot of information about where there are excessive loads of arsenic in groundwater and drinking water sources and those communities impacted.

Katie: One of the places with high levels of arsenic in the drinking water is Bangladesh. And Jess’s group is doing some work there, using locally available materials to filter arsenic from the water. But arsenic is a problem in the US, too. I actually wrote a story about this contamination for C&EN about 2 years ago. Navajo Nation land is contaminated with arsenic and other heavy metals. Scientists have found that about 30% of people living there have no access to clean drinking water.

Jess and Will both spoke about how equitable access to resources motivates their work.

William Tarpeh: The way I think about it is I’m very motivated by science, and how I got into the field had a lot to do with just thinking about the different impacts that, where you’re born and—where you’re born in every sense of where and to whom, and all of these things, what your community looks like, what access your community has to basic resources—can affect so many things, right? And so, for me, I’ve always been interested in thinking about how do we make our very cool technologies work out in all types of settings and in just unique problems and unique opportunities, also. Sometimes we forget about the opportunities in resource-constrained or low-income communities that are posed by these different constraints.

Attabey: Will pointed out that sometimes engineering problems in different parts of the world can lead to different kinds of solutions based on the constraints you encounter. Some of his work has involved sanitation systems in Sub-Saharan Africa, which operate with different constraints than what he might typically encounter with projects in the US.

William Tarpeh: If there are sanitation systems at school, girls are more likely to stay in school. And so for me and my work, what that has meant is a lot of work in Sub-Saharan Africa focused on increasing people’s access to sanitation, to decrease diarrheal disease, increase the number of girls going to school, these types of things. And so those have been big motivators for my work, because sanitation is so fundamental to so many different parts of life. And so for me, what that has meant is that as we design technologies, we’ve piloted them in Kenya, we do some work in Senegal as well.

Katie: Will said working in places where solar panels are the main source of power provides opportunities that might not exist in other places.

William Tarpeh: Sometimes there’s a dichotomy between like tech-savvy techniques or, like, if it’s fancy, and has a bunch of widgets, it should be used in the US, if it’s simple and low-cost, it should be used abroad, especially in Sub-Saharan Africa. And there are ways to subvert that dichotomy for sure, especially with things like solar panels, right? Solar panels and electricity means that we can run electrochemical techniques pretty easily.

Katie: Electricity from solar panels is perfect to use for the kinds of electrochemical reactions he uses for water treatment, and this power source opens up new possibilities.

After listening to Jess and Will, I can’t help but think more deeply about things a lot of us take for granted. Maybe this deeply established water treatment system we have in the US needs to be revamped. Does it make sense that the water that fills the toilet tank is clean enough to drink? Should we be thinking more about the . . . pee-tential in the water we flush down the toilet?

Attabey: Those pee jokes do stick with you, don’t they? I guess urine luck!

Katie: For sure. And I’ll stick with the short showers, too.

Remember at the beginning of the episode, when Will said he gets a lot of advice? To wrap up our conversation, we offered Jess and Will the opportunity to dole out some advice of their own. They both had very practical answers.

Jessica Ray: I think the biggest piece of advice that I got and the biggest piece of advice that I can give to new PIs is time management. So blocking that time for me, including our, like, writing meetings, right, like blocking that time to do work that absolutely has to get done. It’s critical as an assistant professor to block time for writing to, you know, write proposals to get more money to continue, right, the work that we’re doing. So that’s been huge for me, and I tell everyone that.

You do worry about how much time you have, how much money you have as an assistant professor, and all of your many interests, and you have to be really careful about what you say yes to, what hole you want to, you know, decide to jump down and pursue further versus staying more close to home.

William Tarpeh: My, like, short advice would be . . . I think it’s just sort of like identify your strengths and lean into them.

I think on the spectrum of scientists, maybe I’m more intuitive, and so I just allow myself space to like, make a game-time decision sometimes, whether it’s like how to phrase this in a paper or whether we should go for this proposal or that. It’s just a lot of decisions one has to make. I don’t like making decisions about equipment, because I feel like I’ll always have buyer’s remorse. So I very soon got my students in on the, let’s compare quotes together and figure things out, because I just . . . I just got really tired. For every piece of equipment, it was like 30 more questions. And I was like, I don’t know, I just want . . . I just want a pH meter. Please, just a pH meter! And so that decision fatigue, I think, can be real.


And so try to identify your strength or way of doing things and lean into it. And then kind of buttress whatever weaknesses you have, or the parts of your job that are most taxing on you.

Attabey: This episode was written by Katie Bourzac and produced by Kerri Jansen. Story editing by Michael Torrice and Amanda Yarnell. Production assistance from Gina Vitale. The music in this episode was “Different Kind of Love—Instrumental Version,” “Boom-Instrumental Version,” and “Something New—Instrumental Version” by Anthony Lazaro. The promo music was “Plain Loafer” by Kevin MacLeod.

Stereo Chemistry is the official podcast of Chemical & Engineering News. C&EN is an independent news outlet published by the American Chemical Society.

Thanks for listening!.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.