Show Notes
What do you do with human waste in space? Daniel Yeh, winner of the 2014 Cade Prize and a professor at the University of South Florida, invented a solar-powered system that converts human waste into nutrients, energy and water. Initially designed for small villages in the underdeveloped world, the all-in-one waste management system is being tested for use in the Artemis program for a return to the moon in 2024.
TRANSCRIPT:
Intro: 0:01
Inventors and their inventions. Welcome to Radio Cade the podcast from the Cade Museum for Creativity and Invention in Gainesville, Florida. The museum is named after James Robert Cade, who invented Gatorade in 1965. My name is Richard Miles. We'll introduce you to inventors and the things that motivate them, we'll learn about their personal stories, how their inventions work and how their ideas get from the laboratory to the marketplace.
Richard Miles: 0:39
Waste in space, specifically human waste. What do you do with it? And is it good for anything? Welcome to Radio Cade. I'm your host Richard Miles. And today we'll be talking to Daniel Yeh, an engineering professor at the University of South Florida in Tampa, as well as a winner of the 2014 Cade Prize. Welcome to Radio Cade Daniel.
Daniel Yeh: 0:56
Richard it's great to be here. Thanks for having me here.
Richard Miles: 0:58
So Daniel, you've had an incredible ride over the last several years, six years ago, you won the Cade Prize. It was a great moment for you and your team. Now we're going to talk all about that, the technology behind it and so on. But first I'd sort of like to focus on you a little bit. Tell us what the Daniel Yeh story. So you're born to come home from the hospital, then what happens? And then how did you end up in Tampa?
Daniel Yeh: 1:19
So I grew up in Northern New Jersey, I think just typical suburban environment, nothing really exciting. And I was thinking, you might ask me this question. So I was thinking, you know, do I have something, some aha moment as an inventor, right? You people usually point to something when they're living , right ? Somebody gave them some electronic tool kit and that sparks some creativity. No, I think I listened to a lot of music at the time. And that was obviously pre-internet. I just listened to a lot of radio and whenever I can get on the bus and lay down , I was able to drive over New York City, go watch concerts and clubs and whatnot. And that's mostly what I did focus a lot on music.
Richard Miles: 1:55
Are you a musician yourself?
Daniel Yeh: 1:56
That's on my bucket list and to pick up a guitar and play and probably should . Now that you're asking me that. So after high school, I went to the University of Michigan. And for me, that was a world of difference from what I was used to coming from the New York, New Jersey area, being in the Midwest. And I think that experience going to the University of Michigan, being a Midwest really changed my life in many ways, got to see a different perspective of how people are in the Midwest. And of course, I met my wife there.
Richard Miles: 2:24
That helps it.
Daniel Yeh: 2:25
it was life changing for the better.
Richard Miles: 2:27
So we entered the University of Michigan. Did you know you wanted to study engineering or what was your undergraduate major?
Daniel Yeh: 2:31
I did not. So I thought about biology and I was really attracted to nature. That was one thing to have may explain where I am today. I was really attracted to nature. I started out in the school of natural resources and ended up with degrees in natural resources, as well as civil engineering. I even attended forestry camps. I thought I was going to be a forest ranger, but at some point at Michigan, that something clicked. I realized that engineers develop solutions. Engineering is how you get things done. And if I really want, I think, solve problems, I need to become an engineer. So that's where I pivoted and double majored and pursued a degree in civil engineering, the realm of equations.
Richard Miles: 3:07
So you finished up at U M and then what came after that?
Daniel Yeh: 3:09
From there, I went to work, went back to New Jersey to work work for a consulting company, did a lot of computer modeling to study impacts of human development on water bodies. So specifically looking at this case where there's a potential development in a watershed in Northern New Jersey and the pristine watershed and our job as the consultant was to project the impact from that development and how that might impact a water reservoir. So I think that was a good experience because they really got me to think about what constitutes a good computer model. When people say garbage in garbage out, I really understood what that meant. A motto is only as good as the assumptions state you put behind it. It is only as good as the data that you have to formulate a model from there. I decided to go back to Michigan to get my master's degree. And then after I got my master's degree, I worked at Ford Motor Company for a little while. So that was a good experience. Getting industrial engineering, industrial waste management experience. I was part of a research group that was in charge of troubleshooting issues at Ford, almost kind of like a strike force, looking at different issues related to environmental aspects, waste management at Ford. But that's where I think I met my first life-changing mentor. His name is Hyung Kim and Dr. Kim really just loved to talk and give advice. And he said, young man, you need to go South to Georgia Tech because that's where, before he came to Ford, he was teaching and I follow his advice and went to Georgia Tech to pursue my PhD in environmental engineering.
Richard Miles: 4:34
Wow. Yeah . And then you just kept going, he's got a PhD and.
Daniel Yeh: 4:37
Kept going. Yeah, I think that didn't have everything mapped out. A lot of that is just, well in each one of these jobs that I've always felt like, I didn't know enough. I always felt like I could do my work, but I just didn't know enough. Right . There was something that was kind of nagging me. Like I could apply the solution, but, but what constitutes that solution? Like how did people come up with that solution? And I felt like ultimately I really need to get a PhD so I can essentially construct something from zero. And I'm glad I did, because I think that whole PhD process rewires your brain. It does, either breaks you or makes you.
Richard Miles: 5:09
A lot of inventors have unique stories. And when you start out saying that you used to go to New York City, it's funny, I've had two other inventors on the show and they started the exact same way, but the sentence always ends. Like I went to go see like planetariums and science museums. You're the first as I went to music clubs .
Daniel Yeh: 5:24
I did, I went to the village.
Richard Miles: 5:26
And all sorts of ways that you can map out a career path, but that's not a bad one. So Daniel , let's talk about your inventions. And first of all, the work that you've been doing recently, at least since I've met you last six years, you're dealing with most people by definition don't ever want to hear about or talk about it's human waste. And so forgive me, you've probably heard every single poop joke out there by now. You've probably gotten used to it.
Daniel Yeh: 5:47
I've heard most of them, but there's still some good ones. Yeah.
Richard Miles: 5:50
So start out by explaining the technology that won the Cade Prize six years ago, the new generator, which if I remember it was solar, it converted human waste into nutrients, energy, and water, hence the name. And it was essentially like an all in one sanitation slash power slash water system for small villages. And is that essentially what it did.
Daniel Yeh: 6:10
And that's essentially what it is. So the motivation behind this idea is the fact that we have close to 3 billion people on the planet that lacks something that we take for granted e very d ay, which is the ability to go to the bathroom and flush a nd f orget and go about our daily business. And the reason that we're able to flush and forget is because in our society, t here's infrastructure, starting with the toilet itself, then you have a whole series of underground pipes, the pipes in your house, the sewers i n the city, a massive underground network and leading to a wastewater treatment facility that handles that waste and turns it into clean water. Water that's either clean enough to put back into the nature or water that you can recycle for other uses. This system is very expensive to build and probably even more expensive to maintain. So for many parts of the world that are in the emerging economies, they're struggling with t he various infrastructure issues and this type of sanitation infrastructure that we use is really difficult for a lot of cities to build, not to mention t hat for many mega cities, they basically b uilt very organically. So now it's very difficult to go back and basically dig up the entire underground and put all those pipes in.
Richard Miles: 7:18
For these systems that you develop . Can you give us a rough idea of size? I seem to remember they're fairly compact and small.
Daniel Yeh: 7:24
Yeah. So normally you would have this entire factory, right? It looks like a whole factory facility that your domain would be one or multiple in , in a city, depending on the size of a city, like a whole plant. Right? Yeah. And so what we're after is, is there a different way to provide this type of service so that you don't have this build as massive sets of pipes under the ground? And normally the trade-off is that, well, it looks like the only thing that's available is either a latrine, which is essentially a form of hole in the ground or a septic tank of some sort and in the 21st century. And it's incredible information technology age. So there's gotta be different ways to do that. Right. And so the idea is that if we can have essentially a hub of some sort near where people live, those that their waste can enter this hub and the pipe runs would be relatively short, could either be the one hub per house or per a cluster of houses or cluster of public toilets. But this hub would not only safely handled the waste that go a step beyond that. It will view the waste as a resource, not a liability, but extract what we can out of the resource. So that's the water, the energy nutrients, and actually provide value back to the community and this hub, because many parts of the world is crowded. So it can not be very big. So it has to be relatively compact. And what we build are essentially fraction of the size of a 20 foot container.
Richard Miles: 8:40
Really? Yeah. And how are they powered?
Daniel Yeh: 8:42
To date we've built them all solar power. And the reason is in these communities that a re lacking sanitation, they're probably lacking other things as well. And part of the sanitation equation is water, but electricity is another global problem. Many communities either don't have electricity at all, or is severely unreliable. And that's another part o f that cost equation for the US that these treatment plants, we have c onsume a lot of electricity. So we basically need to come up with a low energy system that can run on r enewable. S o it runs on solar, but along the way, we also extract energy out of it in t he form of bio gas that communities can use for heating, cooking, lighting, and so forth.
Richard Miles: 9:17
So something in the size you said that could fit easily into part of a cargo container, what size village could that handle? Both the waste and provide a reasonable amount of power for?
Daniel Yeh: 9:27
The first form we built what we called a new generator, a New Gen 100 serves nominally about a hundred person a day. And that's about a third of the size of 20 foot container . So roughly a foot by six and a half foot wide. So that's the size of that. And then right now we are testing a new generator, 1000, serving a thousand people for about double the size of that. So basically 10 times the capacity at double the size.
Richard Miles: 9:52
And you're currently testing these, I think in India, right? And South Africa is that where you've done most of your testing.
Daniel Yeh: 9:57
We started our testing in India and then later on, because we've had good success, we moved to South Africa and these are all places where there is a significant needs. And we're currently still developing the technology in South Africa. This is all through just the support of the Gates Foundation that had this vision to basically reinvent a toilets that can basically do all those things I described independent of sewer . So basically the next generation of toilets. So we were fortunate to be one of the teams funded by the Gates Foundation to develop these technologies.
Richard Miles: 10:26
How did you get on their radar screen? Was there an application process or did they reach out to you? Or how did that connect happen?
Daniel Yeh: 10:31
So , so after Georgia Tech, I later on move on to Stanford to do my postdoc . And then that's when things start to click in terms of working with wastewater. And so I was working with this technology called an anaerobic membrane bioreactor with another good mentor there , Craig Credo. And this is sort of the latest and greatest technology for waste water treatment. But I always felt like there's an application to apply this for sanitation context. But the thing is nobody would fund that it was difficult to get funding within the US because this is for a global need, right? And then if I go to talk to the NGOs, they tend to want to work with tried and true technologies. There really aren't any resources available to develop transformative technologies. So this thing is we're sort of caught in between, right ? Until the Gates Foundation came along with this program that they want to reinvent the toilet. So it all started in 2011 with a two-page application. They had a program called grand challenges explorations, anybody in the world can apply anybody. You just need to supply two pages. And the first time I applied, I didn't get it. And then I retool made the application better and then apply it again. And then I got it.
Richard Miles: 11:35
And what year are we talking about Daniel?
Daniel Yeh: 11:36
Uh , that was 2011.
Richard Miles: 11:38
2011. Okay. All right . So one more question then before we move on to the space application of this and what you're working on now, I'm imagining that by nature, this is not difficult to both install and fix. So if you put it in a village or any remote area and something goes wrong, do you need to, in an engineer from somewhere, or is there extensive training that's required? Or how long would it take you to train person of average intelligence, how to fix one of these things?
Daniel Yeh: 12:01
So what you described this scenario is exactly the challenges that when we develop technologies for this type of context, often in remote areas. You have to think through. So first of all, the technology needs to be extremely reliable. And you need to think about all the things that may potentially fail. And every machine fails. At some point, if you have a car and you never change the oil, it will fail on you. At some point, you've never inflate your tire. It will fail on you since Henry Ford time. And before we have made so many cars in the world, that we have a good idea to predict reliability, automobiles, that we understand their failure modes and meantime to failure and end to preventative maintenance needed for those. So what we're trying to do is get our technology to that point where we can predict failures, that you can have preventive, maintenance, change out parts before they go out. And then you essentially have a workforce, right? Because one of the issues in lobbies communities also is high unemployment. So you want to create value in the product you're providing so that somebody will pay for this value, this product, this service, which is sanitation, and then employ people who will be trained technicians to serve as the units. And people are very smart and clever anywhere in the world, you go, right ? Somebody will figure out how to solve that need. And right now we're working with some of the smartest people I've ever come across in South Africa. And the prototype engineer that we have working with our sister is just dynamite. So I totally believe that this approach will work, that you make a reliable technology, and then you train a technical workforce to go along with that. And then you create a business model that will sustain that operation .
Richard Miles: 13:34
So let's switch now from the underdeveloped world to space. At some point you attracted the attention of NASA. First question, when I heard that, is that, that , well, hasn't NASA figured this out already. I mean, even astronauts got to go, you know, they they've clearly they've done some work on what you do with human waste in space. So tell us, did they contact you for it's fall or you contacted get them? And what was their request? What were they looking for?
Daniel Yeh: 13:55
So the whole thing was serendipity. I happened to be giving a talk on the space coast at a workshop actually about what we were doing in India. And after my talk, a NASA scientist came over and started talking to me, his name is Luke Robertson. And he said, you know, I've been thinking a lot about how we need to go to this next generation of water recycling in space, because right now on the international space station, we're pretty good at recycling water on international space station. We can recycle even the water in urine. The issue is the amount of chemicals involved to make that whole process happen. And he's worried that when we move beyond the ISS to the moon and then to Mars, this resupply of the chemicals will be either extremely difficult or expensive or just not possible. So NASA kind of needs to go onto this next generation of technologies that might be more biologically inclined that will use less chemicals. So that's one and the other is the need is driven by food production. Well, we need to grow food on Mars, but our current approach doesn't allow us to connect the dots. And I know there's fertilizer and waste, but we need an enabling technology to make that happen. So we started talking and then putting our heads together and applying a lot of the ideas that we developed through the new generator towards what we're currently doing with it NASA.
Richard Miles: 15:09
So I guess the big question, obviously, anything deal with this space is does this work, or can it work in zero gravity or low gravity? Have you done any testing so far? I imagine you have to establish a proof of concept before we go any further, or will you not know that until you get to step on the International Space Station?
Daniel Yeh: 15:26
The very first thing is that we need to have a technology that can show that, you know, if you have a certain type of input into the system, that you can get a certain output out. So meets the requirements of NASA that I can have water that basically looks like water containing toilet water, and out will come clean water, right? It meets their requirements within a certain space. So that's the level that we're at right now, but obviously we're doing this technology on the earth where gravity is present. So while we designed a system with microgravity in mind, we won't really know that until we actually build the next iteration, which hopefully then will be subjected to low gravity situations. So kind of have to climb the ladder. First, first, you need to show that, yeah, I can get it to work. And then the next iteration is okay, I'm going to actually build a version deck, stand up to all the requirements of micro gravity . And then the other is that, you know, micro gravity is not the only setting. If you're looking at surface habitats, whether it's the moon, one, six gravity of the earth or Mars about one third, there's going to be gravity present. So you get to enjoy gravity a little bit in this system you built for this context, although it's going to be a reduced gravity.
Richard Miles: 16:34
So let me make sure I understand this correctly. So in addition to cleaning up the wastewater and converting it to water without chemicals, which is the big advantage compared to what NASA does now, you're also creating fertilizer for plants growing in space. What was NASA's plan before that? Were they just going to truck a bunch of fertilizer up to the moon? Or how did they plan if at all, to grow things on a moon base.
Daniel Yeh: 16:56
Other ideas have often been considered. I think the technology is wasn't there yet because of the focus on making what you currently have work. As you know, right now, NASA is given a budget by Congress and it needs to work within demand days of the budget of their current administrations. So priorities do shift over time. For example, since the Apollo era, we haven't gone back to the moon because the priority has shifted to lower earth orbit. And you can watch all sorts of shows on TV, talking about how this future would have been if we had kept going and gone to Mars. So we would've been there maybe 30 years ago, but it's the focus happened on lower earth orbit. So even though I think in the back of their head has always been the need to develop a different version of the technology, but the focus has been to get things to work on ISS and what they currently have works for the ISS very well. In fact, one of the reasons I got involved working in NASA, well, first of all, who doesn't want to work with NASA, right ? Right. So, but the second is, as an engineer is incredibly challenging and you get to work with some really, really good people. And it also rewires your brain, I think a different way. But under these very difficult constraints, if you can get something to work, you can probably develop something that will work better on earth as well.
Richard Miles: 18:03
So dividends that pay off as you develop something for NASA, you could discover it , it works even better or other applications here.
Daniel Yeh: 18:10
We think so yeah. So for example, we know there's a lot of technologies developed for a space that has since been sound translate to earth like GPS, the algorithms use for talking to the space station is now the algorithm used for laser surgery and the list goes on and on. So we're basically miniaturizing the new generator into something, the size of a refrigerator. And we see that, well, the outcome of this might be something like an appliance household appliances, like refrigerator sized decadent, or just basically handle all the waste as his house generates. But now not only that will give you value back .
Richard Miles: 18:41
Right ? So sketch out for me, Daniel, I know you're still in the testing phase of just making sure this works, but at a conceptual level, what is the idea? Let's say if we have a moon base eventually that has several hundred people or even a thousand people, would it be like what you just described where you'd have these sort of mini units for each household, or is it envisioned that you'd build something like a water treatment plant using your technology just a lot bigger to service the entire base, how much thinking has gone on to, I guess, the scaling up of this type of technology to serve a relatively largish base. And then I'll go ahead and ask my follow-up now is the plan that those would be constructed there on the moon, or would they be constructed here and then brought up there and assembled.
Daniel Yeh: 19:23
I think all of those things that you mentioned are all possible scenarios, right? So right now NASA has planned is 2024 through the Artemis project first woman on the moon next man on the moon that by 2024 and by 2028 to have a sustainable presence on the moon, as a proving ground for technology so that we can put it the first human on Mars by somewhere around 2033. So what's neat is that we get to have the moon to test these technologies before we just build something, think that'll work and then do on Mars. So part of this is also that there's going to be a gateway station, sort of like an ISS that circles the moon. So in terms of building out the moon base, there's a number of ways it could go. And I think you always have to think economy of scale. You obviously, if you have a whole community and you want to put a treatment system in, in every household, it might be better maybe to aggregate the waste and then to have one unit, right, in that case. However, you can also see that this is going to be colony. That will slowly grow. Basically when we go to a place I go to the moon. First thing we're trying to do is not die. It's survival. And just like the first thing that will happen when we land on the Mars is trying not to die because Mars will find all sorts of ways to kill you. So as you get really good at not dying, you transition from survivability to sustainability, how do you actually sustain your presence there ? Using the, these amount of resources, costs, energy, generated the least amount of waste, recycle everything. So whatever technology that's putting , putting up is probably need to grow. You need to have something that maybe is there initially serving one phase of the operation and maybe a smaller scale, and then sort of like Lego blocks, it will grow and be able to serve something larger rather than just shipping something, a mega sized unit overnight. So I think a lot of thinking needs to go in there thinking about how do we put something in there that will not only serve the needs of initial missions, but you get to basically lean on your investment and allow that initial investment to just grow. So that 5, 10 years down the road say, you know, that technology is outdated and basically kind of scrapped it.
Richard Miles: 21:18
I've been talking to a number of folks on this podcast series and we're all working diligently and feverishly on one aspect relating to space. How do we do X or how to do Y do you have an opportunity through NASA or through any other organizations to actually interact with other people in other disciplines, working on space technologies. In other words, do you get a chance to interact with doctors or chemists or biologists focus also maybe part of the Artemis program? Cause I would be fascinated to know, are there areas of overlap in which even though you're in different disciplines, you're actually may be trying to solve versions of the same problem.
Daniel Yeh: 21:49
That's is really interesting. So we work in this realm called Eclss that's environmental control and life support systems. And we work in a subset of Eclss, which is basically water and waste management, but obviously the rest of Eclss in terms of like air revitalization and radiation. I m ean, those are all important things. And I'm also very interested in basically human physiology and psychology because at the end of the day, it's about life support and mission success and how do what we do contribute to that. But how d o w ork other people do affect what we do? I would say probably right now, we're so focused on just trying to get this initial piece of technology to work that haven't had chance to really branch out as much. But I think this w ould just happen as the project grows and maybe I'll do this through my son. He's currently studying biomedical engineering and his goal is to do space medicine. Wow. A nd you think about, this is actually not that long in the future. M aybe in a few years from now, he w ould be up and running during this stuff, I'll be learning from him.
Richard Miles: 22:44
The biggest revolution seems to me in space, exploration has been the involvement of the private sector and specifically private space companies. And you've got this interesting dynamic going on. They obviously still depend on support for math then and oftentimes funding. But in many instances it looks a lot like a private sector initiative in which they're kind of set their own priorities, set their own plans, get at least part of their own funding. So whether it's SpaceX or Blue Origins or Sierra Nevada Space Corporation and others. And we were talking earlier before the show about licensing and so on. Has anyone expressed any interest in your technology from a private company that says, Hey, we want to develop some component of the space program. We really like what you're doing, come work for us or develop this for us or license it to us. How much of role is that playing or is NASA still the major and kind of only driver in this event that we're seeing?
Daniel Yeh: 23:31
So right now we are working with NASA or our goal really is to help them fulfill the mission of Artemis is very ambitious schedule. But what you said there, absolutely I think will happen in terms of licensing of our technology. That's co-developed with NASA to the private sector. So I anticipate that we'll be working with the private sector as well, very soon, because I think right now, most of what the private sector is doing is getting from A to B, having a better way to get from A, to B lower costs. You can't really reuse a rocket from A to B and back, but the question is going to be like, what do you do when you get on B? How do you sustain life there? And if what we're seeing with NASA is any indication, it's more complicated than anybody on earth has ever worked on. And we've gotten good at sustaining life on ISS, but nobody's ever been able to sustain life on the moon for a continuous basis, right . A long, long period. So that's going to be, I think, a challenge for all of humanity to do that. And definitely the private sector will be part of that. So there are not already developed solutions, but at times what happens in the private sector you don't care about because it's a proprietary, but if they're not already developing those solutions, they need to be doing that. And I think there'll be working with NASA to develop those.
Richard Miles: 24:39
I got to ask before we close Daniel, it's not out of the realm of possibility that in 2024 or sometime after that NASA calls you up and says, professor Yeh, we really need someone knows what they're doing to install the first space toilet. Would you be willing to go to the moon and spend however long it takes to put one of your inventions on the moon?
Daniel Yeh: 24:55
Absolutely, but I do hate roller coasters . So I'm not sure how I'm going to survive liftoff.
Richard Miles: 25:01
So avoid the rollercoaster test for as long as you can and maybe NASA won't notice. I got to say, it's fantastic. What you've done. See progress that you've made since we first met you in 2014, I was glad to see that at least a couple of your members of your original team are still with you. I think right from new generator is fantastic and glad to see that and wish you all the best as you continue to research. And certainly as you continue this development for Artemis,
Daniel Yeh: 25:23
Thank you, Richard, you mentioned members of the team and I just have to say that this podcast right now, is it me? I'm the person that's sitting behind the microphone, but this truly has been a team effort from the get go . And I think I've been just very lucky to have had really good people, really good students that I work with. And students usually there's a passion that drives them. They bring their own skill set and perspective to the team and oftentime my role is to just kind of steer them in the right direction. And it's sometimes I just get out of the way and let them do their thing. So I've been very lucky to have that good people. I mentioned people on the original team. One of them is Robert Baer and he's just been the key person behind the scenes.
Richard Miles: 25:58
Well, that sounds perfect boss. Right? You inspire people and they need to step out of the way, right. And go have a sandwich or something. Right? Let your team, figured out the hard stuff.
Daniel Yeh: 26:05
I think a good leader knows when to step out of the way, because you're not necessarily the smartest guy in the room. And if you do your job, you shouldn't be the smartest guy in the room.
Richard Miles: 26:13
No , absolutely. I've heard that before. I've said it in the show as well. If you are the smartest guy in the room, something's wrong, you know, you need to go find some other workers or organization, cause that's probably not a good sign, but Daniel, thank you very much for joining us on Radio Cade and wish you the best of luck and hope to have you back on the show.
Daniel Yeh: 26:28
Thank you, Richard. It's been a pleasure. Great talking to you.
Outro: 26:31
Radio Cade is produced by the Cade Museum for Creativity and Invention located in Gainesville, Florida. Richard Miles is the podcast host and Ellie Thom coordinates, inventor interviews, podcasts are recorded at Heartwood Soundstage and edited and mixed by Bob McPeak . The Radio Cade theme song was produced and performed by Tracy Collins and features violinists, Jacob Lawson.
