This episode originally aired on September 15, 2020.

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. 

The other day, my take-out food came in a container that said it was “certified compostable,” but when I threw it in my backyard compost pile, nothing happened. 

I had Isha Chawla and Fatima Husain from our Possibly team look into this. Welcome, Isha and Fatima!

Isha Chawla: Hello!

Fatima Husain: Hi Megan!

Megan Hall: I’ve seen disposable utensils, straws and containers that are called “certified compostable.” What are these things made of? 

Isha Chawla: They’re all made with bioplastics, which look like regular plastic — but they’re made of plants instead of fossil fuels.

Megan Hall: So, my to-go container said it “turns into soil when commercially composted”. What does that mean? And why didn’t it decompose in my backyard? 

Fatima: “Commercially” is the key word here.

Lee Pollock: They start to break down at a temperature that's above either 150 or 160 degrees Fahrenheit. Most home composting piles are not going to get up to that temperature.

Isha Chawla: That’s Leo Pollock, one of the cofounders of The Compost Plant in Rhode Island, a company that picks up food waste from local businesses and turns it into compost. 

Fatima Husain: He says only commercial facilities get compost up to a temperature that’s high enough to break down those bioplastics. But, good luck finding anyone to accept them. 

Leo Pollock: What we've seen is pretty clearly across the board, composting facilities in southern New England will not take bioplastics.

Megan Hall: What! Really? Why not?

Fatima Husain: Well, remember, bioplastics look just like regular plastics, so it’s pretty easy to get them mixed up.

Isha Chawla: And while that may not be too much of an issue for us, it can be a real problem for the people managing our waste.

Fatima Husain: Bioplastics can’t be recycled with regular plastics. And it’s expensive for recyclers to look through and separate them. Sometimes, too many bioplastics in a recycling batch can contaminate the entire load, which means it has to be thrown out.

Isha Chawla: You have the same problem when people accidentally put regular plastics into a compost bin, and that means the plastic can contaminate the compost. 

Fatima Husain: Leo says it’s just not worth the hassle.

Leo Pollock: Bioplastics really don't add any nutritional or quantitative benefit to the compost. And when the contamination rates go up, that really degrades the quality of whatever the product they're producing.

Megan Hall: But I see these compostable plastics at all sorts of places!  

Isha Chawla: That’s a problem — because if they aren’t getting composted, which they usually aren’t, then they’re either messing up the recycling system or going straight to the landfill.

Megan Hall: Well, what’s the solution?

Fatima Husain: Leo says it’s pretty simple — cut down on using single-use items. 

Leo Pollock: How do we get into a mindset where whenever we leave the house, we keep in our car a reusable fork and knife and a cup that can handle hot or cold drinks. If most people did that daily, that would decrease the amount of single use plastic or bioplastic significantly.

Isha Chawla: While plastic is very toxic and takes ages to break down, it doesn’t solve our problem just to move to other materials. What we really need to do is work on changing our patterns of consumption.

Megan Hall: Ok, but if I do get a container that says it’s made of bioplastics, what should I do?

Fatima Husain: Your best bet is to try to find another use for that container — you can use it to store odds and ends. 

Isha Chawla: But whatever you do, don’t recycle it. So, unless you use a commercial composting plant that accepts bioplastics, the best thing to do is actually throw it away.

Megan Hall: Great! Thanks, Isha and Fatima! 

That’s it for today.

Possibly is a co-production of the Institute at Brown for Environment and Society and the Public’s Radio.