Bringing Chemistry to Life

One person’s waste is another's treasure

Episode Summary

This captivating conversation with Dr. Will Tarpeh from Stanford University centers on the how chemistry is finding ways to recover valuable resources from wastes. His innovative way of thinking stands to provide economic incentives to develop applications with tangible benefits for human life and the environment.

Episode Notes

80% of waste water gets discharged untreated, which causes some of the most urgent environmental issues facing our planet. However, Dr. William Tarpeh, nominated as one of The Root 100's most influential African Americans, views waste water is an incredible resource that contains many valuable components and represents an untapped economic opportunity in our world of finite resources. 

This episode is an intriguing discovery of how chemical engineering can transform our energy-intense linear economy, where materials are made, used and eventually discarded, into a new circular economy based on recovery value and a vision of eliminating waste altogether. 

William and Paolo speak about how selective adsorbent resins and electrochemical processes can completely change the chemical landscape and profoundly impact the global economy. This episode is a treasure trove of examples of how chemical innovation can change the world and how great science can translate into practical applications with immediate tangible benefits for human life and the environment.

Episode Transcription

Dr. Will Tarpeh  0:05  

80% of wastewater that's generated around the world isn't collected, it just goes out into the environment, often without treatment. And so we're talking billions of litres of wastewater being discharged to the environment. It's a threat for pollution, of course, and it's a lost opportunity.


Paolo  0:24  

Will Tarpeh assistant professor of chemical engineering at Stanford University is focused on harnessing that lost opportunity with wastewater through chemistry. It's what landed him on the Chemical and Engineering New's 2019 Talented 12, a list of brilliant young scientists taking some of the world's toughest problems with clever chemistry. And it's also how we came to be one of the most prominent young scientists on thechemical scene, being named one of the 100 most influential African Americans by the Root and appearing in Forbes 30, under 30. In the science category, in the sixth and final episode of the Science with a Twist series, Bringing Chemistry to Life, we speak with one last member of the Talented 12 about their work and trends in their field. I'm your host, Paolo Braiuca, Senior Manager of global market development at Thermo Fisher Scientific. We began by asking Dr. Tarpeh about this background, and what took him to his current role.


Dr. Will Tarpeh  1:22  

I was born in West Africa and my my dad is Liberian, my mom is black American. And so I grew up kind of between the West Coast of Africa and East Coast of the US, I found myself as a child really fascinated by science and always by the environment. So I was always really interested in how things worked. Around me being in nature and thinking about it. I also thought a lot about how science could impact people's lives in terms of improving people's lives. That got me really interested in eventually in water, but kind of meandering through all different types of science. I was, as a kid, I was really interested in paleontology, I loved doing fossil digs that I, I would hide fossils for myself, and then and then find them a couple weeks later, that was like, really exciting to me that element of discovery when I look back at it, but I got interested really in water, kind of in middle school, high school. And then even more interested in wastewater. Drinking water is really clean, very aspirational. Wastewater, we view as the exact opposite in so many ways, but they're often connected in the cycle that we don't always acknowledge, we might install a well or think about ways to clean up drinking water. But we don't think about the fact all the time that wastewater often becomes someone else's drinking water. What people treat as trash and discharge, there's value in it, and what if we could recover it? And that's really the backdrop for everything we do in my lab is how do we, the quote we often think of is one person's trash is another person's treasure. And we're the second person. So that's how we think about it.


Paolo  2:49  

What is the main driver, here is your interest for nature, you're interested in people, you're interest in making a difference, because, you know, you could potentially take on an area that was under, not particularly looked after?


Dr. Will Tarpeh  3:04  

The drivers are twofold. One is, I love really interesting science. I love a good scientific challenge and pulling the needle out of the haystack from a chemical perspective. So that's always driven me. And then I was always driven by really tangibly improving someone's life. So when I did internships in college, I was the ones I was most excited about. Were the ones where I could meet the people who's who's who were the motivation for my work, right. So like, doing work in sanitation, I could meet people who benefited from toilet installations and things like that, that was really gratifying for me, and helped drive the discovery and the scientific part because I could think of early on, it was like, I could think of that person, right. But now it's easy for me to just say, Oh, I can think of this group of people who I think would benefit from these innovations. So I love doing fundamental science, but with the application like really already in mind.


Paolo  3:51  

I think this is a recurring theme. And there's always this sort of correlation between the love for science and the problem solving aspect that most scientists have, but also with this drive and desire to make it real right to ensure that you impact life. And what is wastewater really, how much of it we have, and what the reason he that is valuable?


Dr. Will Tarpeh  4:16  

When I think about the definition of wastewater, in most cases, any industry any installation that has a physical pipe that takes some liquid stream and discharged it to the environment, once it crosses the physical boundary of that installation. I'm interested, it's the wastewater part. And so that broadens the definition because most the time when I say wastewater, the picture that pops into people's minds, is a wastewater treatment plant. I love to broaden that definition. Because there are many different types of wastewater, they're all different, they have different compositions and thus they have different value because they have different components. So wineries have wastewater, any chemical industry you can think of as wastewater but so does agriculture. Right? So do there's so many things that generate wastewater. So it's water that goes out into the environment. And in terms of how much there is 80% of wastewater that's generated around the world isn't collected, right? So it's just, it just goes out into the environment, often without treatment. And this is worldwide. And so we're talking billions of liters of wastewater being discharged to the environment. It's a threat for pollution, of course. And it's a lost opportunity, a series of lost opportunities, because we put all this money into generating these valuable chemicals. And then we discharge some portion of them, large portion of them into the environment.


Paolo  5:34  

So spending energy and money to generate value, and then discharging a lot of this value into the environment and forgetting about it and then keep spending money to regenerate it.


Dr. Will Tarpeh  5:44  

That's not a bad thing. I don't mean to demonize it. I just think in the 20th century, we weren't as aware of pollution as we are now we weren't as aware of the costs of the linear economy, nor were we as aware of the opportunities of a circular economy. Now we know there's we're putting money in and we're leaving money on the table.


Paolo  6:00  

If I think about all the different wastewaters definition that you just described me, what are you really focusing on? Are you really looking at all of them?


Dr. Will Tarpeh  6:10  

We definitely cut off a bite sized pieces that we're most interested in. But definitely the big vision, we I hope that in 20 to 30 years, people ask me what wastewater is. And it's like that term is obsolete because it doesn't exist because there's no such thing as wastewater, that's kind of the vision I work toward, in the same way inspired by biology, right. So like, ecosystems don't have the same concept of waste, right? One organism's waste is another organism's input. That type of circularity is what I would love to see and what I what me and my group work towards in terms of the chemical industry. But in terms of the compositions of these different wastewaters, the few pieces that we take on one that's really captured our imagination is the nitrogen cycle. Inorganic nitrogen in particular, there's so many different forms of nitrogen, they have different oxidation states, we can convert them between each other. Nitrogen is so captivating to us, because it's one of the cycles that humans have changed the most. So we have all this reactive nitrogen that we're pumping into the environment with very little removal of it. And so we take that a step further and say, let's not just remove it, because that would take two energy intensive processes, right. Haber-Bosch, and then conventional nitrogen removal. Let's recover it, let's keep it as reactive nitrogen, we've already done the work of reducing it to ammonium. Let's keep it that way. And so that's something that has captured our imagination. Part of me keeps trying to get away from it and diversify, but I just keep getting pulled back into it. So now we're thinking about nitrate, ammonium, what about gaseous nitrogen? Right NOx emissions, and tool emission? How many of these Can we turn into valuable products. So that's one big area of the work. Another area we've got really interested in is desalination. And there's lots of work going on on desalination, turning seawater or wastewater or brackish water into potable water. Our perspective on that is that even desalination generates wastewater. So if you take ocean water, you'll make less salty water that's potable, you will also make a volume of saltier water. And that brine is something that we still can get value from. And so that's what we're after. So even in kind of green technologies, we're still after squeezing all the value out.


Paolo  8:12  

Is the vision, taking one by one, these different types of chemistry in a different types of wastewater. And overall, the vision, long term vision is that we will have circular economies for all the wastes.  


Dr. Will Tarpeh  8:26  

I tend to view circular economies as actually elements specific. So I, we talk about a circular nitrogen economy, but there should also be a circular phosphorus economy. I view these as loops of each element that you can look at. And then we ask questions like How many times can one molecule of nitrogen go through our industrial ecology? And how much value can we get to like seventh generation nitrogen? Right? So maybe you've seen like, Seventh Generation dishwashing liquid? Can we get seventh generation nitrogen? What would that look like?


Paolo  8:53  

And that makes a lot of sense to me, because I imagine the chemistry for each element is going to be fundamentally different. So you actually need to tackle the different circles with different kinds of approaches. So they have to be looked at in isolation.  


Dr. Will Tarpeh  9:06  

Absolutely, right.So when we think about the separations that we design, whether they're electrochemical or adsorbent-based on the different characteristics we we exploit to get just nitrogen out, they might be things like hydrated ionic radius, or electronegativity. These sorts of things to get nitrogen away from potassium or sodium. There's a different logic. If we want to think about lithium. Lithium is another thing, we've started thinking about. Lithium has a whole different mechanism of selectivity, so to speak, it's hydrated radius is really different from sodium, ammonium, and potassium. So we call these sort of like resource recovery cases. And it's kind of a three part thing that we think about. It's like, what's your target wastewater? What's the wastewater where this nitrogen or whatever element you're after is present at high concentrations. Then there's the target element, what element are you after? And then there's the target product. Are you trying to make a fertilizer Are you trying to make a disinfectant? So with those three things we sort of juggle those around to make our each resource recovery case that motivates a line of research.


Paolo  10:06  

But I assume that wastewater are more complicated than that. You don't only have nitrogen pollutants only or phosphate pollutants, you know, you're gonna mix of those things. So is the vision sort of combining all these different cycles somehow, by sort of pre-processing of the original water stream, dividing it in separate wastewater types that can be treated separately chemically or physically?


Dr. Will Tarpeh  10:32  

To your question of different wastewaters having different compositions? Absolutely. Because we absolutely think about that and leverage that because it does some of the separations work for us. So as an example, another thing that we continue to do, and I really just own now, so my C&EN moniker was, the Waste Wizard, is the Waste Wizard. And so this is a thing my group has really owned. So I dress up for it, this will be my second Halloween dressing up as a Waste Wizard. But part of that is because one of the thing that has captured our imagination a lot is urine, human urine. And so sometimes people who I meet are like, "Oh, you're the urine guy." And I'm like, okay, that's one of my, one thing I go by not the cheif thing, but it's one thing I go by. And that's because urine is one of these cases urine is 1% of the wastewater volume that's generated municipal wastewater, but it has 80% of the nitrogen in it. So it's, it's done the work for us, right, our bodies have done the work for us in terms of if we want nitrogen from municipal wastewater, getting it from urine is 100 times easier than getting it from municipal combined wastewater because it gets diluted a hundredfold. And so that's why we go after urine, because the separation, it's like the pretreatment you mentioned, there's a pretreatment their urine is high in nitrogen, it's going to be an easier separation. Let's go for that.


Paolo  11:45  

It's a perfect model system for you guys. And, okay, why is nitrogen consider a pollutant, you mentioned the fact that humans actually affected the homeostasis of the natural environment, to skewing the equilibria. And I believe that nature just can't cope with that. So there's no mechanism to go back to a perfect equilibrium, like when human didn't have the Haber-Bosch, and they were making so many fertilizers and explosives, Is it that and what does this imbalance cause to the environment?


Dr. Will Tarpeh  12:15  

The major forms of nitrogen that cause pollution in water are ammonium (NH4+) and nitrate (NO3-). Now both of these contribute to harmful algal blooms, which in environmental science, we call eutrophication. So if you've seen that green, green, kind of slimy muck layer on water, that often is seasonal, when you go to the beach, or when you go to a lake, these sorts of things, or even a river. These algal blooms are often not always caused, but exacerbated by excess nitrogen emissions. And so what that cycle looks like is, ammonium and nitrate are the main food sources for these algae that continue to overpopulate, they continue to reproduce, because there's plenty of food around, they're very happy. And so that over consumes oxygen and leads to hypoxic zones in the water column. This affects aquatic ecosystems by changing the food chain, and can even affect higher order like fish kills. And so one of the places we think about is the the Gulf of Mexico, where one of these dead zones emerges at the mouth of the Mississippi River every year, and it's about the size of the state of New Jersey. And when I read this, in an environmental science paper, I was like flabbergasted. And this happens every year, let alone this also happens in the Great Lakes too, like, those are some of the problems that ammonium and nitrate can cause. In addition, nitrate when it's present in drinking water, can pose threats specifically to infants and can cause a syndrome called Blue Baby Syndrome. But eutrophication is really the main thing we think about. And the main thing we want to prevent when it comes to natural pollution.


Paolo  13:45  

Are there currently any chemical physical processes to remove nitrates or nitrogen compounds from from the wastewater at all?


Dr. Will Tarpeh  13:54  

There are some processes that already do a great job of removing nitrogen one such as nitrification denitrification, a pair of coupled processes that are biological in nature. So it's a great removal process it generates N2, it fills that cycle. And so like in that arrow diagram that we're thinking of the nitrogen removal part, the part that is balanced on the anthropogenic side is wastewater nitrogenremoval. It's a fantastic process. It's not a bad process. Our approach is just that it's still energy intensive. And often nitrifiers are the bacteria that do nitrification are the slowest growing in a wastewater treatment plant. And so that leads to larger wastewater treatment plants, because you need more time for them to grow. And so we've used this as a compliment. It's not, we don't want to get rid of nitrogen removal. It's a great process, but most wastewater treatment plants don't have it. And so we need to think about additional tools in our toolbox.


Paolo  14:46  

Let's think about the strategies you use them. So how'd you how do you go for this shortcut? So what are the ways you actually recover the nitrogen in the ammonium form?


Dr. Will Tarpeh  14:56  

Right? How do you extract only ammonium, let's take ammonium or nitrate, how do we only extract ammonium from a very complex wastewater stream? This calls for a really high selectivity. And the selectivity is so important because we're going to make products, right. So if you're just removing nitrogen, you can just oxidize lots of things you can oxidize and then reduce lots of things. And it's you don't care so much about what happens in the rest of the water column. But if you're recovering a product like ammonium fertilizer, or ammonium hydroxide, we challenge ourselves to meet the same purity that those products are made with normally. As an analogy, right with the dishwasher liquid we make, we don't want to come up with a new way for you to wash your dishes, in addition to making a new dishwasher, so right, we just want to have another dishwasher soap on the shelf, so to speak.  


Paolo  15:44  

You said that it's a very complex affinity property you have because you have a complex stream. And then you need to play with the charge and the pKa. And so you're designing I'm assuming some sort of specific ligands that are selected for the ammonium and not for whatever else, you have in the stream. What are you using as a bed resin? Are these the standard ion exchange type of things?


Dr. Will Tarpeh  16:11  

Yeah, so we've we've done a few things we first started off, when I first got to Stanford, we started with this big molecular screen, we were like, let's look at all the different we were using some acrylamide monomers, and we were making our own beads. And this was promising but wasn't getting us the selectivity, we desired, we thought we needed to make the casting even wider net. And so we sort of repositioned and said, Okay, what if we go for rather than making our own beads from scratch? What if we start with ion exchange resins and modify them? And this has a few advantages. One, people are more familiar with these. Two, we can it decreases the like level of adaptation one would need, right so. And what we've done now is we pass transition metals over these ion exchange rates and these cation exchange resins. Load things like zinc or copper onto them. And that becomes our liquid exchange site. So we do ion exchange, and then ligand exchange. And so then the challenge for us is how do we get ammonium, to become ammonia and then do ligand exchange without displacing the metal that we just loaded on? Right. And so the interesting thing about absorption that we think about a lot is getting the ammonia on is one part like removing the ammonia from the solution. The second part that's just as important for us in the recovery process is the regeneration of the resin, right? How do you use it multiple times, because when you do the regeneration, that's when you actually make our product, you make your nitrogen-rich liquid waste stream. So in this version, what we need to do is get the ammonia off, but keep the transition metal on. Right. And so then that's how we start to play with the regeneration. And that's like kind of that what's the right recipe of terms of pH to do the regeneration?


Paolo  17:48  

And you certainly have enough contaminants in your water stream. You don't want to add transition metals to it right?  


Dr. Will Tarpeh  17:54  

You don't want to leach those transition metals. And so we tested this in our first paper on this because we were really concerned we want to make sure we weren't adding transition metals. And with that we were using fairly acidic pH is to get the ammonia off. But we were able to find kind of a happy medium, but around pH 1.5, to 2 where the transition metal didn't ellute at like 100th, the rate of ammonia which we said, Okay, that's good enough for proof of concept. We've got more to do on the regeneration side.


Paolo  17:54  

But what the overall process economics?


Dr. Will Tarpeh  17:55  

Ah, fantastic question. So the we've done this with existing adsorbents. We haven't done it with our new adsorbents yet. But the first thing I did as a PhD student actually was try to survey different adsorbents for their nitrogen selectivity. And think about these unit economics. What we saw kind of intuitive parts right are the more times you can regenerate, the lower your cost gets. Right, because that extends the lifetime of your, of your resin. And so that decreases your the metric we're after is cost per kilogram of nitrogen. An interesting finding was that in terms of cost, we were able to beat the cost of conventional nitrification de-nitrification. Now, this is important because actually the comparison that we should be making to your earlier point is our process which does removal and recovery, we need to compare it to the sum of removal and recovery. Right, which should be Haber-Bosch, which is not recovery, but production plus nitrification de-nitrification. And so this is a really important thing to communicate in our work because sometimes people will, people from wastewater treatment will say, "Oh, you didn't beat nitrification de-nitrification." And I'm like, Yes, we may not have, but you're forgetting about Haber-Bosch. And then people who think about fertilizer production will say, "Oh, but you didn't Haber-Bosch." And I'm like, yes, we may not have beat Haber-Bosch, but but we were doing two there two value propositions here, right? We're not just getting the nitrogen out. We're getting it out and turning it into a valuable product. So in terms of cost, we did some also a field study in Kenya when I was a PhD student and found that urine-derived fertilizers were actually lower costs than fertilizers available to farmers in Kenya. And this has some kind of unique aspects because most fertilizer in Kenya is imported. And so there are markups that actually are in our favor. So the value of urine-derived fertilizer is that it's locally sourced. Right? You can have as long as you have people, and there's urine and you can make fertilizer. But in the US, we're certainly not beating the cost of Haber-Bosch yet. So we have to think about how to market this in terms of it's not just cost, but energy, environmental impacts, and also constantly how to reduce cost, because cost often will take the day.


Paolo  20:22  

Yeah, that rules. I'm just curious, what is the cost determining factor in the whole process? Is it the cost of the resin or the number of times you can recycle it?


Dr. Will Tarpeh  20:32  

Most of the time, it's the number of times you can recycle it. That's one metric that we're very interested in. Another aspect of it is the chemical inputs you need for regeneration. And so this happens for cost and energy actually.


Paolo  20:46  

It's fantastic. And this is the typical pragmatic approach of chemical engineers. They look at systems and try to integrate system is beautiful how you do that. And we can go on forever on this one, just curious about your electrochemical approach. So how does it look like in practice, this is such a big reactor ar a battery, is this like really implementable on the field? How do you envision that?


Dr. Will Tarpeh  21:11  

Yeah, it is. So in our lab, it's something that fits in my hands, right? So I'm big hands, but it's about it's about, it's about 10 centimeters by 10 centimeters, the outer parts are, and then across total, it's maybe 15-20 centimeters. And that's because of the many chambers that are stacked up. But these are all made of we make them out of Plexiglass. But kind of the first prototype we made is this is this, a bit that fits and fits into your hands, that size can treat about 10 liters a day. And so this to us is is promising because it's it can be used in decentralized settings, right? It doesn't need a ton of input. And in terms of the power draw, it's around 5 volts. In many cases, it can be powered by solar panel, right. And so this is something that we we envision we haven't done yet, but it's just hooking up a solar panel to our system, rather than an amazing potentiostat to control experiments. But for implementation, you can just hook up a solar panels or hope use that electricity to constantly recover ammonia. And so some of the one of the big questions we're after from the engineering side is what's the optimal scale of our process? Right? How do you what do you know about the optimal scale? And so these are some questions that our engineers are thinking about.


Paolo  22:18  

How does it compare economically with the absorption process?


Dr. Will Tarpeh  22:21  

Great question. So it's, it's more expensive in terms of capital costs, because we have membranes, electrodes, and we use fairly, they're not the most expensive electrodes, they're mixed metal oxides, titanium coated with radium oxides often made often for the chlor alkali process or other other water based like aqueous electric chemical processes. But between the electrodes and the membranes, it's about tends to be like an order of magnitude higher in capital costs. But then what we're after, again, is lifetime. And so then operating costs can be lower for the electrochemical process, because you're not constantly adding acid, for example, you just have one batch of acid sitting there that's constantly receiving ammonium.


Paolo  23:01  

What is in your mind a better system? Do they compete with each other? Or do you see any synergy there?


Dr. Will Tarpeh  23:06  

For a while we compared them a lot and it's sort of like because we sort of developed them at the same time like in parallel and so it's like Okay, which one is better and we ended up doing more on the ion exchange in terms of practical nature, because it was there the electrochemistry was more like the electrochemical reactive separation took more time to to really design and engineer well. Interestingly, now, so to me, they go in different settings, right. So in a place that so like, one can, the ion exchange column can run without too many pumps, and without too many moving parts, right? And it's more established, right? If I go into the water industry and say, oh, I've got an ion exchange column for you. They'll be like, "Oh, great, hook it up. No problem." If I go and tell them I've got this great electrochemical stripping process for you. They're like, "Tell me more" like they're either like "Tell me more" or like "No not interested." But it just there's more adaptation needed for the electrochemical process, but water is getting increasingly electrified. So people are starting to get get used to that more. I will say one of the things I'm really excited about is combining these I mentioned using sulfuric acid to regenerate resins. One thing that's captured our our thoughts a lot recently is can we use electrochemistry to regenerate the resin bed. And in so doing, avoid the input of the sulfuric acid and just regenerate it on the spot. So our first iteration of this in a paper we just wrote up in Water Research is using electrochemical water splitting just normal electrochemical, water splitting and kind of old news in some ways, but using it to make ion exchange regenerants. And knowing that we don't have to make them at normally ion exchange regenerants are either really high in salt concentration, or they're like pH 2, pH 1 or 2, or pH 13 or 14 they're extreme right? And so we said what if we make it more like pH3 and 11 electrochemically and see if we can we can regenerate some pH sensitive resins and we were able to so in this case, the resin isn't in the electric chemical cell. You make the regenerant electrochemically and then pump it through the column. Our next steps that I'm relaxing About our Can we put the resin in the cell?


Paolo  25:02  

You have already demonstrated that these things can be used in practice or you've done the study in Kenya to really change potentially life of people in you can affect the local economy. For that, you turn pee which is basically free of charge right? into valuable fertilizer in a fairly efficient way. How much? Or how far are we from having either of the system or their combinations and synergy available as a commercial product and widely utilized, at least in some specific situations or markets?


Dr. Will Tarpeh  25:32  

My answer right now is on the order of 5 to 10 years. I think from from commercial, so not not very far away. We've recently kind of intensified our startup efforts being at at Stanford and in Silicon Valley, we've been thinking more about this in electro-san, which is how we identify ourselves and on the venture scene. But what we're really after here is taking advantage of some of the wonderful kind of networks we have at Stanford and get their input on what do you think are the best cases what what's our what's the best target market for this? Another thing I'll mention in terms of the implementation is we're finding new applications that honestly I hadn't even thought of, which is another exciting part of doing science. But NASA has gotten very interested in some of our work. And one of my students, was just identified as a NASA fellow. Because, again, going back to pee, right, we can another place where we need to make value from pee is in space. on the International Space Station, there's already some urine treatment going on there. Most recently, we've been talking about the lunar moon base, right? Making consumables from from urine, rather than shipping them up at millions of dollars per payload.


Paolo  26:42  

You have so many ideas, right? And you take a lot of inspirations from the results of your work in potential applications and on the constant drive to improve the economics and efficiency of your systems. But is there any other way you get inspired? What are your ideas coming from?  


Dr. Will Tarpeh  26:59  

Oh. I read a lot. I like to read for fun. And I like to read things kind of out of the box from science that actually brings me back to ways to tell the story of the research and draw new connections, I find that that I tell my students often that like writing proposals and lots of the work that a that a principal investigator does is actually very creative, trying to capture someone else's imagination with our idea and convince them for funding or convince a student to join your lab these things. Because of the NASA thing, I really got really interested in reading books like The Martian, etc, things like that, that are sort of, to me seem futuristic, but maybe are within the next decade, which is really mind boggling to me. I also find inspiration for my science, just when I'm talking to friends being around family community, one of my friends, close friends got a new fish in the new aquarium. And I overheard someone in the pet store talking about sensing nitrate and nitrite. And I was like, Oh my gosh, I didn't thought about this, we should be thinking about aquaria. And so we had been thinking about changing adapting some of our treatment techniques to sensors. And I was like, I have to think more about this. So I like impulse bought of not a whole aquarium, but a nitrite paper testing kit. And I brought it back to my lab. But I said students guess what happened to me today. And they sort of now they're used to this. And so it's still sitting in the lab because the pandemic happened, we haven't really gotten to opening it. But these are the things that really capture my imagination, I just, I guess I tried to leave space in my mind and in my life to like get inspired spontaneously. And that and that really helps. Of course, going back to kind of my roots in terms of nature inspiring me is another another big part of thing. So like, sometimes it's looking at a body of water and thinking what would have looked like San Francisco Bay if we did this. So what would it really look like to have resource recovery plants all around the bay, that type of thing. So


Paolo  28:45  

it's great. I mean, you have such a creative mind and this drive and you're you always keep it open and you're you're ready for it. And us that's really what defines a brilliant creative mind like yours is It's fantastic to see you describing to hear you this kind of thing. There's a question I always ask, you know, what is the single piece of advice that you would give to a young scientist just starting your career now that you are still a young scientist, but already saw accomplished?


Dr. Will Tarpeh  29:18  

Hmm, one piece of advice I give my students a lot is exactly what we were just talking about. Try to remain inspired and remain open to new ideas. Because I think the most exciting talks I see are the most exciting scientists I see nowadays are often combining ideas from different fields in a new way, or putting new ideas together just in a way no one has quite thought about. And I think so much of it is actually influenced by your personal experience too. And so sometimes people think like, Oh, I don't have this pedigree and so this disqualify that disqualifies me from science or things like that. And I it's so important to me that we include everyone because we need everyone's experience and personality to have these great ideas. So I guess I really trust in the serendipity of putting brilliant people together in rooms and seeing what comes out as much as possible, I suggest to young scientists to try to put yourself in those rooms. And also, of course, work hard. We all are passionate about our science, but leave some margin there to have the serendipitous conversation that we were talking before this Paolo about the thing that might lead to what we're missing in conferences, right? Is that serendipitous content 10% of time you don't plan you just leave. And you see what happens, right? Maybe it's not 10%. Maybe it's 30 for you or I don't know 50, or 80. But leave some time where you're just open to a conversation learning about a new field that curiosity I think is really important. So stay curious and try to put yourself in positions to learn from new people. And we try to draw connections between what you're doing and someone else is doing.


Paolo  30:54  

That was Dr. Will Tarpeh, Assistant Professor of chemical engineering at Stanford University, and one Chemical and Engineering New's Talented 12. Thanks for joining us for this final episode of season one or Bringing Chemistry to Life, a Science with a Twist series. You can visit for special access to our guest profile sheets, which has more information about Dr. Tarpeh, recent publications from his group and his content recommendations. This episode was produced by Matt Ferris, Gabriel Orama and Emma-Jean Weinstein.