Episode 57: Dr. Bruce Logan on Environmental Engineering and Microbial Fuel Cells

Introduction

0:00Hi, you're listening to Let's Talk Chemistry, a podcast by Chemtalk. On today's episode, we interview Dr. Bruce Logan, a professor of environmental engineering and director of the Institute of Energy and Environment at Penn State. He talks about fuel cells, climate change, and more. We hope you enjoy.

0:22Hello, and welcome back to Let's Talk Chemistry, a science podcast by Chemtalk. I'm John, I'll be one of your co-hosts. And I'm Jasmine. In some of our last few episodes, we've featured guests that specialize in various aspects of earth and environmental science. Today, we're continuing that trend with Dr. Bruce Logan, an environmental engineer at Penn State University. We have an abundance of Dr. Logan's insight to share throughout this episode that spans a variety of topics, from renewable energy to climate change.

Guest Background

0:51Let's first start with a bit of background on our guest. My name's Bruce Logan. I have a PhD in environmental engineering from UC Berkeley, BS and MS degrees from Rensselaer Polytechnic Institute in chemical engineering and environmental engineering. I'm currently the director of the Institute of Energy and the Environment at Penn State University. I'm a faculty member in the Department of Civil and Environmental Engineering, and also chemical engineering. That's a lot of hats to wear, and they cover a large spectrum of environmental science.

1:26But what kind of work do these roles translate to? Here's Dr. Logan on his current area of research.

Renewable Energy Research

1:32So, I work on renewable energy, primarily from the perspective of the sustainability of the water infrastructure. So, I've done work, wide range of topics, but mostly in bioelectrochemical systems, which is the study of microorganisms that can either generate or release an electric current, electrons, to and from an electrode. I also work on water electrolyzers and novel membranes in those systems, desalination, and

2:06renewable methane and renewable hydrogen production. Of the topics mentioned, these electricity-producing microorganisms, which we'll come to know as microbial fuel cells, stand out amongst the rest. Dr. Logan goes on to elaborate on the functionality and application of these fuel cells. I've been working with microbial fuel cells for many years now, and these cells are based on the ability of bacteria to degrade organic matter and release electrons to an electrode,

2:40and thereby, we can capture that flow of electrons as electricity. So, think of some of the science fiction movies you've seen where, you know, people are hooked up in making electricity, a lot of the matrix, or all these, you know, innovative ways that people make power. We actually study bacteria that could make electricity. And so, we have been studying them for, oh, probably nearly 20 years now in terms of their ability to not only convert organic matter, waste organic matter, biomass into electricity,

3:13but also with additional power put into the system, they can actually evolve hydrogen gas. So, we can get hydrogen for transportation, other applications, and we can use that to also make methane using special microorganisms on a cathode that turn that hydrogen into methane. Harnessing the electricity of bacteria is an inventive and valuable scientific feat. Naturally, it raises some questions, such as, can we do this with just any form of bacteria?

3:48And does working with this bacteria pose any risks? While the science behind these microorganisms is compelling, keep in mind that the big picture of Dr. Logan's work is in renewable and alternative energy. One of his areas of expertise that was alluded to earlier was the water infrastructure. When it comes to these systems, Dr. Logan explains the role that these microbial field cells play in maximizing efficiency and conserving energy. Anybody who's been outside of a box in recent years knows that the world is focusing on renewable

4:21energy. And so, we're interested in using all the resources that we can, and we're developing solar and wind and so forth. But then there are applications where you don't, maybe you don't want to have to use those, or you don't want to use much of that. One of the main things that we look at is the water infrastructure. In the U.S., about 5% of our electricity production can go into the water infrastructure, treating wastewater, cleaning water, pumping water, and so forth.

4:54And if you build all water activities into that, which includes heating water and, like I said, pumping and irrigation, it can be as much as 15% of our electricity that goes into that. So, there's a lot of energy that goes into our water infrastructure. And if every country on the planet wanted to have a very industrialized water infrastructure, where would that energy come from? So, what we're looking at is trying to use these microorganisms and the energy inherent in wastewater as a source of energy.

5:24And by capturing that energy, we could make these wastewater treatment plants power themselves. So, it certainly wouldn't solve everything, but being able to deal with this used water or wastewater and to have no additional energy demands on that system, that would be really wonderful. With the world attempting to shift to more conservative means of energy production, this idea of creating self-sufficiency in our water treatment plant sounds like a tremendous asset.

5:55This could allow for other energy sources to be allocated toward various everyday applications. Especially given the perspective of the statistics Dr. Logan enlightened us with. Something else to consider is that certain forms of energy may not be as accessible to some parts of the world. Northern countries that don't receive as much sunlight wouldn't make use of solar energy the same way warmer climates could, for example. These microorganisms, on the other hand, are much more ubiquitous and accessible across the globe. These are large-scale challenges that the scientific community is confronted with daily, and some

6:30of the work being done to find solutions is quite unique.

Career Path

6:33So, how does one find themselves in the world of environmental engineering and conducting research in a renewable energy niche? For Dr. Logan, his journey was motivated by a sense of curiosity as well as the desire to make a difference. So, I grew up, like many people in high school, you take all the subjects, you do all these extracurricular activities, and then one day somebody says, oh, you have to choose one. And you think, oh my gosh, how am I going to do that? And so, I thought about doing something related to the environment.

7:06And when I talked to people, they said, well, if you really, do you want to study the environment or do you want to actually go and solve environmental problems? And I said, yeah, solve environmental problems. I said, well, you should be an environmental engineer. He said, oh, okay. So, I looked into that. And then when I was an undergraduate, at first I was majoring in environmental engineering at RPI. And then as I looked at the curriculum, I realized that courses I needed to succeed in this were more in chemical engineering.

7:37And so, I took, within chemical engineering, not only a lot of math, but a lot of chemistry. And so, you really had this nice background, this fundamental background in both the math, which you need to do the applied work in engineering, and the chemistry, which you need to do to develop the processes and understand what's going on in environmental systems and in engineered systems. And so, that was really pivotal. That was when I decided to get a chemical engineering degree, but then I continued on in environmental

8:08engineering. And specifically, I would never go back for a PhD, that I wanted to go out and change the world. And I had worked about two years, and I decided to go back and get my PhD. And people said, well, you know, what was the realization there? And I said, well, I looked at what people did, and I looked at the people that did all the interesting jobs. And all of those people had PhDs. And I thought, well, if I want to do this really interesting work, I guess I have to get

8:41a PhD so that I can learn to do that. And, you know, so that's how I ended up with a PhD. You know, it's never a certain pathway. People used to say pipelines, but it's never a pipeline. It's a pathway. We all wander along and kind of go in different directions and do different things. That's quite the journey, and demonstrates how dynamic the life of a scientist can be. Dr. Logan's career reveals just how interconnected the mechanisms of our world are through the

9:13various fundamentals at play. This can lead to many surprises, as well as exciting discoveries, like the one Dr. Logan made while studying the phenomenon of marine snow. Now, to tell you the most exciting discovery is a little bit away from the work I'm currently doing. Actually, my most exciting discovery came in the form of studying particles in the ocean. Now, particles in the ocean turn out to be really important to climate change now, because if you want to sequester carbon in the ocean, it's got to get way down deep into the bottom

9:47sediments and effectively out of the sort of whole food chain. And so, we were studying the formation of something called marine snow, and think about snowflakes, what they look like, but when you're underwater, they kind of look, you see these little amorphous particles, and they call that marine snow, because it looks like snow, but it's in the marine environment, so it has nothing to do with cold temperatures or anything like that. And the problem was that people said that can't form, because they calculated how many smaller

10:22particles there were and how fast those particles could collide and come together. And based on our calculations, there weren't enough particles to make that aggregate of particles. And so, it's kind of like the bumblebee, you know, people say, oh, you know, the bumblebee shouldn't be able to fly, but it doesn't know that. So, it does, you know, because it can't beat its wings fast enough, and it's too big, and all that sort of thing. So, our greatest discovery was that we figured out how these particles could form.

10:54And what happened was, we did an experiment, and we counted particles, and indeed, we didn't have enough particles. And then we looked, and there were these sort of somewhat invisible particles in there. They were formed by polygors that phytoplankton excreted. And when you look at the number of those particles that were nearly invisible, then you could form the aggregate. So, we were seeing these aggregates that were essentially formed by invisible particles.

11:27And we just realized that in just that one moment, it was quite a discovery for us because we really had crossed that line of understanding. And it took, you know, it was a day-long experiment, but we made that discovery in the span of about five minutes. So, that was, you know, that was really exciting. Very few times you can look in the lab and say, that was the instant that I made that discovery. When Dr. Logan talked about wanting to do the interesting jobs, he certainly meant it. Not only are the science and math skills needed, but there is an investigative quality to unraveling

12:01these mysteries that makes for some detective work. And these discoveries aren't limited by their interesting nature. They have practical and relevant implications to the challenges facing us today, such as Dr. Logan's reference to climate change and the sequestering of carbon. Right. Every scientist hopes for a moment of discovery or epiphany, like the marine snow moment Dr. Logan just described. His interest in microbial fuel cells was piqued in a similar moment of revelation during a conference in Utah, which he shared with us here.

12:31You know, scientists always talk, oh, we go to these meetings, we talk about our work, and everybody's like, yeah, you're just going to, you know, have fun at the conference. I'm like, no, we go to conferences. So I was thinking about what I wanted to do in the renewable energy space, and I went to a conference in Salt Lake City, and I went to a poster session, and I was reading posters. And I saw this poster from this one guy from South Korea, and I looked at it, and it just was like, that's what I'm going to do. And he had been studying how these iron-reducing bacteria could actually essentially discharge

13:07without, we didn't need to add in any chemicals. And I thought, wow, we could treat wastewater with that and make electricity. I'm going to work on that. So next day, I went back to my university. I grabbed one of my students and said, you're going to start working on this.

13:25And we did. And that's really, you know, that was most of my, probably what I'm known. And that occurred because I just happened to see a poster. You really never know what the catalyst for inspiration is going to be or when it will appear. And after a long career working as an environmental engineer, Dr. Logan declares the following as the biggest challenge currently facing the environmental science field. I think the environmental engineering field needs to evolve. For a while, the environmental engineering field just focused on essentially wastewater,

13:59treating water before it went into the environment that, you know, this used water. And then they said, well, you know, we need to treat water more efficiently than we do now. And they started chlorinating it and doing a better job of that. So they were doing water and wastewater. And then one day somebody said, oh, what about all these chemicals in the ground? Oh, well, we need to clean those up. So environmental engineers started working on that. And they're like, well, what about air pollutants? Environmental engineers started working on that. What about solid waste? We started working on that.

14:30Hazardous waste. We started working on that. Climate change actually is being driven by waste CO2 and other greenhouse gases. And I don't think the environmental engineering profession is taking that challenge on as well or as efficiently as they need to. So, for example, historically, we worried about solid waste. And each person in the U.S. produces about three to five pounds of solid waste a day.

15:01And we collect it. We haul it out to the curb. Somebody comes. We have this whole infrastructure, right? Garbage trucks, taking it to a landfill, capping it and safely disposing of it. If you used a gallon of gas a day in your car, you are essentially taking about 20 pounds of CO2 out to the curb every day. So, 20 pounds of CO2, and we just throw it up in the air. Goodbye. Three to five pounds of garbage.

15:32Oh, we carefully cultivate that. We put it in the ground, you know. But there's no air fill like there is a landfill. So, we keep putting this up into the air. And it's a lot. I mean, it's like the weight of a, you know, a mature man every week going out to the curb as waste CO2. Well, that's a lot of CO2. And so, I don't think people really appreciate the mass of CO2 that we're throwing out every day just from a gallon of gas. That doesn't include our home, you know, and food and the energy to produce that food.

16:05So, I really think we need to be looking at climate change. And if you were to use existing technologies to capture the CO2 that was released from your gallon of gasoline, the price of gas would go from like $4 a gallon to $14 a gallon.

16:25That's pretty expensive. And so, it's not like you can pass this charge on to the consumer because they're not going to pay $14 a gallon. But I think if they realized the impact of that, maybe that would help this transition to electric vehicles. So, you know, I think this is the next challenge for environmental engineers. You know, from your perspective, for the people in chemistry is to understand the chemistry of how we can capture that CO2 more effectively and sequester it.

16:55And so, that's a, you know, that's our global challenge right now. Despite the growing threats and alarming statistics, Dr. Logan has a more optimistic perspective on society's current approach to climate change.

Climate Change Discussion

17:09But in an age where change is crucial, how can we effectively educate the population on the importance and significance of these challenges? Acknowledgement of the issue is important, but it shouldn't stop there. Understanding of these issues should serve as a harbinger for the action needed to effectively change behavior that is inducing the excessive amounts of CO2 emissions. And as we discuss the topic of climate change further, it is worth considering our sources of information. Dr. Logan shared with us that his research led to him writing a book, which he titled, Daily Energy Use and Carbon Emissions.

17:44The inspiration for this book came from other works that existed at the time. Dr. Logan recognized that there was a plenty of information written about climate change itself and its causes. But writers tended to focus on the details and not so much on how energy use ties to carbon emissions. This is especially important as climate change is directly related to increasing carbon in the atmosphere. I was definitely interested in the link between energy and carbon emission, as I believe this information isn't as common knowledge as other concepts related to climate change.

18:17Sometimes, quantifying concepts also helps us to understand them better. Thus, one of Dr. Logan's goals is repairing the disconnect of daily activities with carbon emissions. And it seems he's been quite successful in communicating this topic. He shared a couple examples with us, the first being a comparison between the energy use of your car and in your home in one day. What uses more energy, your house or a car on average every day? Actually, they use about the same amount of energy.

18:47I mean, on average, a person uses about one of the quarter gallons of gasoline a day per person. But on average, about two and a half people in a house and the amount of energy that uses. A house uses about 900 kilowatt hours or 30 kilowatt hours a day. A gallon of gasoline is about 35 kilowatt hours. So, depending on how many people are in the car and how many people are in the house and everything else, they're about even. Or you could say, yeah, the car may use more energy than even the house. So, it varies. Whether you're in nice, warm Southern California or you're in Maine, well, there's going to be quite a difference in the amount of home energy you use.

19:24So, we can say, you know, about average. But that's the sort of thing that, you know, I think the energy in a gallon of gasoline is something that people really don't understand. I found this surprising. Ever since being in elementary school, I remember being encouraged to use a bike instead of a car for transportation. I truly underestimated the impact, though, because even short distances driven in your car can add up quickly. Agreed. I've always loved bike riding for recreational purposes, but with the context of the climate, it inspires me to go beyond recreation and consider what's practical and helpful.

19:59It's interesting to relate this distance to the power of electricity it would provide my home. Speaking of power and energy, Dr. Logan also shared a unique comparison. A stick of dynamite and a bar of butter. A stick of dynamite and a bar of butter. How many bars of butter equal the energy in a stick of dynamite? I think, you know, most people say, you know, I've had some people say, oh, it must be like 100, you know, 100. Because you never think of a bar of butter being a lot of energy.

20:29Actually, it's a trick question because there's actually only a third of a bar of butter equals the energy in a stick of dynamite. It's about 800 calories in a bar of butter and about 250 calories or kilocalories, really, but calories, capital C, in a stick of dynamite. And you're like, well, how can that be? It's like, well, that energy is released instantaneously from the stick of dynamite, but not from the butter.

21:01So it's those things and thinking about energy and power, you know, like a lot of people, you know, think of something more powerful uses more energy. And whether you run a mile or walk a mile, you don't burn much difference in calories. I found that to be such a fun and remarkable way to think about energy. Relating energy and food to energy and other sources also helps consider the impact of our consumption. It's so important to ensure the information provided to the public is both accurate and understandable to be truly impactful.

21:33Definitely. And Dr. Logan didn't end this mission with the writing of his book. As editor of the journal Environmental Science and Technology Letters, Dr. Logan was instrumental in making scientific research more accessible to members of the public. The goal was to bring environmental search and stories very quickly out of the laboratory and into awareness. And so we set up a very rapid review cycle. These were shorter papers so they could be reviewed more quickly.

22:07And we would generally, within two weeks from submission, an author would have a decision. And so that enabled people to very quickly get their results out. And particularly like when during coronavirus, when people were worried about aerosols, there was a lot of very fast aerosol research being published there. So, yeah, it was just a way to very, very good review. I mean, the people that reviewed for the journal were good experts in the field.

22:39We didn't just push anything through. And in fact, we had a pretty high rejection rate. If it didn't need to be urgently published, we would say you should use the regular submission process. But the idea of environmental science and technology was to bring up rapidly stories about emerging contaminants or new chemicals or particular pollutants or priorities that people would want to know about. As topics like climate change become more crucial to understand, regular publications of research keep people appropriately informed.

23:14As I looked at things, I realized that it was actually an interesting job and it would always stay interesting. And when you first get a job, it's always interesting. But after six months, maybe not so much. After 20 years, not so much. And so I think science and, you know, whether it's chemistry or physics or math or whatever it might be, it keeps it interesting because it continually changes.

23:49And there's always new challenges. And then why become a professor? I ask students, well, what do you want in your job? Well, I want to travel. You know, I want to meet people. I want to do challenging things. I want to work on things I think are important. I said, you just described my job. I work on things that are important. I travel. I, you know, meet interesting people. You're in the lab. You're talking with people. You're working with people. There's a lot of communication that occurs as being a professor in academia.

24:21And I think maybe students don't always see that. And they think their professors work very hard. Well, you know, we do. But look at somebody who's a VP for a company, too. I mean, you can choose how hard you want to work and to what level you want to succeed. The best jobs always do require a fair amount of work. I wouldn't say I work any harder than anybody else in a company that's, you know, moving up in the company. So those would be my points.

24:53Most importantly, Dr. Logan advises us to pursue a field in which we have an existing interest. Yeah, I think the key for me and for many others is, number one, find an area that you're interested in. And then when you find an area you're interested in, look for something you can be passionate about. Maybe young scientists say, well, I know how to be passionate in other ways, but I'm not so sure I could be passionate about science. And you can't expect to immediately find that. I think it's something that you look for.

25:23And as you get into a field that you're interested in, you look to see where you'll develop that passion. And for me, it was finding something that was really thrilling, whether it was particles in the ocean, how do they form? Going out on boats and being out there for two weeks with divers and marine scientists, that was exciting to figure out that microorganisms can make electricity. How do they do that? How do we harness that? That became exciting. So I think it's important not to expect that to happen at day one, but, you know, you pursue some interests and exciting things will happen along the way.

25:58And when that comes along and you start to really get engaged in something, follow it. It gets to be really good. I found this insight to be especially helpful since the idea of finding your passion can feel daunting. However, hopefully Dr. Lowland's advice provides encouragement as you learn to navigate this process. Thank you again for joining us on today's episode of Let's Talk Chemistry. And we hope to see you next time. Bye for now.

26:25Thank you for listening to Let's Talk Chemistry, a podcast by Chemtalk. We hope you enjoyed it. For more information on today's episode and countless chemistry resources, please visit our website at www.chemistrytalk.org.