Podcast transcript
Generating power from pond muck
Dr Ashley Franks
Audio
You can also listen to the interview [MP3 9.9MB].
iTunes
Visit this channel at La Trobe on iTunesU.
Transcript
- Matt Smith
Welcome to a La Trobe University podcast. I would be your host Matt Smith and today I’ll be speaking with Dr Ashley Franks, a microbiologist from La Trobe University. He’ll be speaking to me about his research involving a certain type of bacteria and how it could be used as an alternate source of power.
- Ashley Franks
Most people always associate bacteria with disease and only with disease, but what they forget is that less than one per cent of bacteria on this planet actually cause human disease. Bacteria do a huge range of things. They are tiny little microbes that we can’t see by our eye. They’re the smallest things on earth. You can fit thousands of them on a pin head. They actually drive all the processes in our environment. So they look after things like getting rid of all the organics, they give us nitrogen for the soil, they help plants grow, they clean up all the waste, they produce most of the oxygen that we breathe. Basically if we all disappeared, the earth would be fine. If bacteria disappeared, then everything would stop, ceasing. We need bacteria. We’ve actually got ten times the amount of bacteria in our stomachs than we do human cells, so we’re more bacteria than we are people. You know, most people think of them as bad, but they make cheese for us, they make beer, they do very sort of important processes.
- Matt Smith
Very important. You’ve been doing work with bacteria and harnessing energy. How does bacteria go about harnessing energy and is it every bacteria that can do this?
- Ashley Franks
I work with a special type of bacteria that is quite unusual because when we breathe, we breathe oxygen. But these bacteria, they live in the soil where there is no oxygen. So when they breathe, what they end up doing is using other things like metals. So these bacteria are actually breathing metal. And we breathe oxygen by taking it in, but metal’s a big solid surface, so what they have to do is go up, and usually things like iron oxides. The bacteria go up and touch the iron oxide and transfer electrons. So breathing is giving electrons to oxygen for us, whereas for the bacteria, it’s giving electron to the solid lumps of iron oxides in the ground. And if, instead of iron oxide, you give them an electrode, what you can do is, you can actually gather the electrons that these bacteria are breathing. So it is just a natural process like us breathing, but instead of using oxygen, these bacteria are now using an electrode, and using these devices called microbial fuel cells, we can collect all that energy as electricity, in the form of basically a biological battery.
- Matt Smith
You’ve got an example right here in front of you. I guess the easiest way would be for you to tell me how is this working.
- Ashley Franks
This one’s what we call a sediment microbial fuel cell, and all it’s doing is, it’s got a graphite cloth in some sediment, so just in some dirt from the bottom of a pond, and what is happening is that the bacteria in there, they are using that electrode, that carbon cloth, as an electron acceptor. So they are breathing out by actually giving electricity to it. The electrons then go up through a wire, go up to the top to another electrode over the top, which we call a cathode, which combines with oxygen, so this is basically working in the exact same way as your normal alkaline battery would. You just have a negative and a positive, you have a reaction where electrons go from one point to another. In your alkaline battery, it’s all chemicals, but in this sediment fuel cell, what it is is the actual bacteria breathing that generates that electricity. And we can use that, in this case, to run a little light.
- Matt Smith
Yeah. You’ve got a jar of mud that’s making a light blink red.
- Ashley Franks
Yep. And that’s all through bacteria just breathing electricity.
- Matt Smith
So, how often would you have to feed that bacteria?
- Ashley Franks
At the moment, we’re not quite sure, because we’ve had one running for three years, because what the bacteria do, is eat all the organic matter in that mud. Organic compounds, like leftover wood, or your compost heap, has heaps of energy if you can get it, and the bacteria know how to get all that energy and convert it all into electricity. And the great thing with this is that if we actually ever did run out of the organics in here, we just have to put more mud in.
- Matt Smith
Now, that’s all very well for making a little light blink for three years, but what’s the practical applications of something like that? How much mud would it take to say, power a laptop?
- Ashley Franks
One of the interesting things with this, is that it gives you a small amount of constant electricity. So this small amount of constant electricity can come from a natural source, and what that natural source can be, is just mud. So, if you actually had sensors in the ocean, or if you actually wanted to monitor streams, or if you wanted to do somewhere way, way, way out from everything else, you could easily bury these in mud, the local bacteria will give you energy, and you could keep on supplying as much energy as you want to power your little … check the temperature, salinity, whatever you’d like. There are a group in Washington that work with the American Navy. They have one of these – it’s about a metre square, they can bury that in the ocean, and it gives you the same amount of energy as about 39 D cell batteries each year. So a low level amount of energy, but it’s constant and it’s free and you never have to go back and re-supply it. So if you’re thinking of monitoring something in the Mariana Trench, it’s going to cost you two million dollars to get a submarine down there, but if you can bury this then the bacteria can go and generate your electricity. And the more you put in series, the more energy you can produce. But one of the things too, that’s useful with this, is that you can use whatever waste organics that you want. So if it’s something like a food factory, you’d have to treat all its leftover produce or its leftover waste, which has got lots of organics, but what you can do is convert that into electricity. And at the moment, you could even do it with waste water, so when you flush your toilet, and waste water in America uses about 7 to 9 per cent of the total energy production for the whole of the US. So even if you didn’t make it in net energy, you could save 9 per cent of the actual energy output of the whole country, which would be fairly significant in itself.
- Matt Smith
With that bacteria from waste water then, you’d be setting up, say, a waste water plant. So do we need to look at the services that we’re using?
- Ashley Franks
Yes, I think at the moment we spend a lot of energy, and a lot of money, to treat the waste water to make it into clean water and to get rid of that waste. And I think the thing, what we need to be doing, is looking at other ways, where we can actually reduce that cost, and reduce those energy inputs we need to put into it, and also we’ve got also a resource of energy in our waste, so whether it is through making electricity, or making methane, we could get something back from it, whereas at the moment we just treat it, and get rid of it, and we put energy into it, but get nothing back. I think that with a bit more research and a bit more insight, we could actually be able to reduce, because at the moment the technology that we have seems to work, so there’s no emphasis at the moment to do anything new or put more money in, or make any changes, even though in the long term there could be a lot of benefit for us.
- Matt Smith
So what specifically are you guys working on here in the microbiology department?
- Ashley Franks
So what we’re looking at is the actual bacteria, the molecular mechanisms that can do this. Because this type of process is actually quite unusual, for microbes to be actually transfer electricity outside of themselves. If you think of a tree, or you think of grass, you don’t think of something that’s going to conduct electricity. Normally these things stop electricity from actually transfer, so what we’re interested in is these special, what we call bacterial biofilms, so when bacteria is able to stick to these electrode surfaces, how they’re actually able to get electricity outside themselves, how they’re able to connect with these electrodes, and we’ve actually been doing some work recently too, to show how bacteria, some of them are actually feeding each other the electricity.
- Matt Smith
Right.
- Ashley Franks
So these bacteria can interact and they feed each other electricity, and do things directly through these processes, centropic processes with each other, using electrons. And people before recently didn’t realise that this could happen. They thought that bacteria interact by giving each other sugars, or nutrients, or things they didn’t realise that they could do it directly with electricity. And there’s just a wide range of applications and important processes in the environment, that now need to be re-looked at, that could involve bacteria and electricity.
- Matt Smith
There’s something that I always find about bacteria, though, is that it can survive anywhere and can adapt to any thing. So isn’t this just an aspect of it that’s surviving and putting metals to use?
- Ashley Franks
Yep. A lot of the things that we think we’re very clever at, bacteria have already been doing, because one of the interesting things with these electric bacteria, is that some of them you can feed electricity to, and you can actually get them to produce petrol from carbon dioxide. So at the moment, the big problem is, is that you burn petrol and it makes carbon dioxide, but some of these bacteria, you could give electricity to and reverse that, and you get a fuel source. So it’s like a nice bio-energy, or a bio-fuel. It’s only a few years old, but it’s one of those things which potentially in the future may be a very alternative, natural way to get rid of carbon dioxide and give us energy. But also too, we could power these bacteria directly with energy, and get them to produce a lot of different types of products, whether they be bio-fuels, specialty chemicals, or getting the bacteria to produce what we want, using natural products. Because we always think we’re I guess clever, being able to do these type of things ourselves, but what we’re finding is, these natural evolution already have all these processes in nature, if only we know where to look and how to harness them.
- Matt Smith
Dr Ashley Franks there, environmental microbiologist, along with his jar of pond muck. That’s all the time we have for the La Trobe University podcast today. If you have any questions, comments or feedback about this podcast, or any other, then send us an email at podcast@latrobe.edu.au.
Focused, Ambitious and Transformative ideas - 
