It turns out, there’s a way to capture methane before it leaks into the atmosphere. In the case of a landfill, you can cover the surface and then install vent pipes to capture the gas. And for manure and food waste, you can use something called an “Anaerobic Digester.” Anaerobic Digesters sound complicated, but they’re really just contraptions that grow the right mix of microbes to break down all that organic waste and produce methane.
Digesters come in a few different shapes and sizes. But on farms, they are usually a series of large tanks that look a little like the bubbles you see over indoor tennis courts. They hold the manure in air-tight conditions and collect the methane as it rises up off of the waste. Once the methane is captured, it can be turned into natural gas. So, not only do you prevent methane from getting into the atmosphere, you also can also use it for energy.
Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall.
A few weeks ago, we had an episode on methane. Methane is the main ingredient in natural gas and it contributes to climate change when it leaks into the atmosphere from places like pipelines, landfills, and piles of manure.
It turns out, there’s a way to make these methane leaks less of a problem and more of a solution.
Here to explain how are Cate Ryan and Harrison Katz from our Possibly Team. Welcome, Cate and Harrison!
Cate Ryan: Hi, Megan!
Harrison Katz: Hello!
Megan Hall: So, Harrison, is there a way to turn these methane leaks into a climate solution?
Harrison Katz: The short answer is yes – if we can capture those leaks before they end up in the atmosphere.
Megan Hall: How can we capture leaking methane??
Cate Ryan: Well, to understand how this works, it’s useful to know a little more about how methane is created in the first place.
Harrison Katz: To find out, we called Jose Amador, a professor at the University of Rhode Island who studies Soil and microorganisms.
Cate Ryan: He says that when organic material, like food waste or manure, decomposes, it can emit methane because of the microbes that break it down.
Jose Amador: They are super tiny. You cannot see them with the naked eye.
Cate Ryan: These microbes basically “eat” organic material by breaking it down into smaller and smaller pieces.
Jose Amador: So I’m a microbe … Right? I see a large fiber and I’m like, ooh, dinner.
Harrison Katz: And when this feeding frenzy is over, one of the things the microbes “spit out” is gas.
Cate Ryan: If this process happens in a place with oxygen, the microbes release carbon dioxide. If it happens without oxygen, you get both carbon dioxide and methane.
Megan Hall: OK, so how do you capture this methane?
Harrison Katz: In the case of a landfill, you can cover the surface and then install vent pipes to capture the gas.
Cate Ryan: And for manure and food waste, you can use something called an “Anaerobic Digester.”
Megan Hall: What is that?
Harrison Katz: Anaerobic Digesters sound complicated, but they’re really just contraptions that grow the right mix of microbes to break down all that organic waste and produce methane.
Megan Hall: What do these digesters look like?
Cate Ryan: Digesters come in a few different shapes and sizes. But on farms, they are usually a series of large tanks that look a little like the bubbles you see over indoor tennis courts.
Harrison Katz: They hold the manure in air-tight conditions and collect the methane as it rises up off of the waste.
Cate Ryan: Being airtight is important — you don’t want the methane to escape. ALSO, if oxygen seeps into the manure, the microbes won’t create as much methane.
Harrison Katz: Once the methane is captured, it can be turned into natural gas. So, not only do you prevent methane from getting into the atmosphere, you also can also use it for energy.
Cate: And the waste those microbes leave behind can be repurposed as fertilizer.
Megan Hall: Cool! How many places actually use these Anaerobic Digesters?
Cate Ryan According to the EPA, as of January 2019 there were 248 digesters at farms across the US.
Megan Hall: That doesn’t seem like a lot. Why so few?
Harrison Katz: Well, according to Dawn King, a professor at Brown University who studies urban agriculture and energy policy, these systems aren’t cheap.
Dawn King: Part of the problem is really scale, and that it can be really expensive to get a legitimate digester. But when you do, it’s super cool.
Cate Ryan: Luckily, the technology is improving, and Dawn says anaerobic digesters are already worth the investment, especially for large institutions.
Dawn King: You’re taking something that really is a horrible pollutant and instead you’re harnessing that and creating something that will push it back into the energy cycle, right?
Harrison Katz: Like with all alternative energy, the prices will fall as more people invest in anaerobic digesters. And then maybe more places can take advantage of this technology.
Megan Hall: Great! Thanks, Cate and Harrison!
That’s it for today. For more information, or to ask a question about the way you recycle, use energy, or make any other choice that affects the planet, go to the public’s radio dot org slash possibly.
Possibly is a co-production of the Institute at Brown for Environment and Society and the Public’s Radio.
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Citations
Here is where we got the stat about the number of digesters in the US. This site also explains what a digester can look like on a farm-
Methane is a really horrible pollutant compared to CO2- https://www.sciencedaily.com/releases/2014/03/140327111724.htm
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