Biodegradable or Compostable? Here's the Difference
Everyone thinks they know the difference between compostable and biodegradable ‘til they’re asked about the details. Then things get more complicated. In a perfect case of marketing appealing to what we hope is true—rather than the actual truth—lots of compostable products turn out to be… well… not compostable.
Why? Because while single-use plastic is cheap, customers today want sustainable options. Those cost more, so rather than increase product costs, it’s easier to frame single-use plastic as eco-friendly.
Compostable: Better than Recyclable?
So you just opened that awesome thing in the mail and now you have to dispose of the packaging responsibly. Ah nice! The label says 100% compostable. That means you can toss it in the garden right? Or does it just break down faster in a landfill? Do you recycle it?
Who the hell knows?!
Biodegradable, compostable and recyclable get used interchangeably, but they don’t mean the same thing. Why does it feel so confusing? What aren’t businesses telling us?
Let’s make like a recycling plant and break it down.
How Long Does It Take to Break Down?
Everything on Earth is biodegradable depending on your timeframe. Plastic, car batteries, even nuclear warheads all eventually break down, just not for thousands of years and after emitting all sorts of toxic gases.
So let’s reframe that definition.
Biodegradable items should break down within a year at most. Stuff like newspaper, banana peels and pine cones doesn’t need any help returning to nature because bacteria can snack on them—tasty! No matter how much heat or water is present, biodegradable items fully break down and go back into the ground.
If everything is biodegradable, then compostable items should definitely be good to go.
Wait, You Can’t Compost That?
Do you think composting is where worms and fungus biodegrade stuff? You know, the same biodegradable process as organic material but while also enriching soil?
If plastic is compostable, shouldn’t it break down nicely in a compost bin within just a few weeks?
Does this sound like your idea of compostable? If so, welcome to the club of people who misunderstand bioplastics! No need to be embarrassed. These companies spend ungodly sums to do exactly that—engineer public opinion—and they are experts at it.
Guess what! Compostable plastic is not compostable except under special conditions that only exist in super expensive industrial plants. Not only can’t they go into your home compost bin, they can’t go in the recycling bin either!
GIF OF SCREAMING
What’s Different about Compostable Plastic?
The truth is that single-use plastics haven’t changed much. Rather than PET, compostable plastic is a polymer called PLA that comes from vegetable oil. The catch is that PLA doesn’t break down like vegetables, and if you toss it into the recycling bin, it can contaminate all the other plastic.
So even vegetable-made single-use plastics turn out to be just that—single-use. For compostable plastics to be recycled, all you have to do is find one of the rare industrial composting sites that accepts these materials. Easy.
Why Isn’t Bioplastic Biodegradable?
At this point, you’re probably wondering why plastic made from corn or beans doesn’t biodegrade like corn or beans. It’s a good question.
Plastic is made from all kinds of stuff, kind of like how you can freeze both water and chicken broth. Ice is a state of matter; so is plastic.
No matter what you use to make plastic, the molecules undergo a process called polymerization to become durable. What is polymerization? It’s how you chain molecules together to make a strong bond.
Once molecules are chained together in a polymer, it takes a lot to break them apart. This means that while bacteria want to eat the molecules inside the chain, they can only see them from behind the glass, like a zoo. Until the polymer wall breaks down—a process that takes years—bioplastics break down just like regular plastics, meaning hardly at all.
Bioplastic has to be composted at special facilities under temperatures of about 150°F for nearly 2 months! Even if you left a bioplastic cup outside in Death Valley, California, it wouldn’t break down any faster than normal plastic. What the hell?
So What Is Compostable?
For starters, not plastic. Sorry, but aside from that, lots of stuff is compostable. Coffee grounds, paper, cloths, even hair makes for good worm food. It would be nice if compostable plastic were, ya know, compostable, but since it isn’t, bioplastic ends up next to most single-use plastic: in the trash.
To sum up, compostable plastic isn’t recyclable, recyclable plastic isn’t compostable, and biodegradable just breaks down eventually. As usual, the only way to fix this problem is to stop the ‘buy, use, toss’ cycle and make major changes to our lifestyle.