The Hidden Difference Between Biodegradable and Compostable

Redefining responsible waste disposal

A person holding a metal bowl and walking through some containers and bins
Cleanup (Image by JJ Ying from Unsplash)

We hear the terms ‘biodegradable’ and ‘compostable’ all the time when talking about effective waste management.

But what’s the actual difference between the two terms? And what implications does this have for the environment, when we’re preparing for materials’ end of life scenarios?

Consumers are becoming more conscious of their environmental impact, and companies are realising the demand for more eco-friendly packaging. Both ‘biodegradable’ and ‘compostable’ are highly marketable terms for companies.

But they don’t hold the same meaning, and it’s vital we don’t treat them as if they do.

Learning the difference is important so we can:

  • 🗑 Make more sustainable purchasing decisions

In this guide, you’ll learn the fundamental differences between biodegradable and compostable waste.

A person wearing blue jeans sitting in a red shopping cart
A person wearing blue jeans sitting in a red shopping cart
Decisions, decisions (Image by Jeremias Oliveira from Pexels)

What does biodegradable mean?

Taking the Merriam-Webster dictionary definition, it’s something:

…capable of being broken down, especially into innocuous products, by the action of living things (such as microorganisms)

This is as specific as it can get, as there are no official requirements to be allowed to label something as biodegradable.

And that’s a problem because, in reality, biodegradable items often don’t decompose quickly enough to have any measurable benefit on the environment. They can take 6 months or hundreds of years to break down.

If you think about that timescale, we could technically class all plastic as biodegradable, since it technically won’t be around forever. It’s an empty term.

And the better biodegradable items still need exposure to the correct microorganisms to actually decompose.

This was demonstrated when a study by the University of Plymouth’s International Marine Litter Research Unit found biodegradable plastic bags that were still strong enough to hold shopping after 3 years exposed to sea, air and earth.

There’s also no requirement that biodegradable items aren’t allowed to leave toxic residue behind when they do disintegrate into the soil.

What does compostable mean?

All compostable things are also biodegradable, but not all biodegradable things are compostable. Does this feel like one of those IQ test questions yet?

We’ve all witnessed fruits and vegetables decompose at an inspiring rate wherever they are (bin juice, anyone?).

But labelling anything other than plants as ‘compostable’ requires certification. ASTM, a global standards committee, have set the definition: a compostable item must be able to break down in an industrial (usually council) composting facility within 180 days.

What does ‘breaking down’ mean?

Exposed to the right levels of carbon and nitrogen, compostable items must form fertile compost. And this must leave no toxic residue behind — just water, carbon dioxide and biomass (the icky stuff).

A yellow excavator in a garbage mountain
A yellow excavator in a garbage mountain
Vast (Image by Tom Fisk from Pexels)

Compostable plastics still need the correct amounts of heat, water, oxygen and microorganisms, so often can’t be composted at home. They need to be sent to a compost facility. If a collection service is even available where someone lives, there are other energy and cost-consuming factors once the waste reaches the facility.

However, composting by its nature will probably break down materials at least somewhat, even when the conditions are less than ideal.

A note on Oxo-degradables — a.k.a. Satan’s bioplastic

Oxo-degradables are an attempt at greenwashing by some deeply irresponsible companies.

They’re conventional plastic materials infused with artificial chemicals, which cause them to degrade under UV light, heat or oxygen. However, the oxo-degradable breaks down into small fragments of plastic and later microplastics, which endanger wildlife and the environment.

There’s no evidence the product will break down within a reasonable timeframe either.

Oxo-degradables also threaten the standard of recycling and composting facilities. We can’t effectively sort them with current technology, so they just compromise the quality of recycled plastic. 🙄

A person leaning into a wall near some bins and rubbish bags
A person leaning into a wall near some bins and rubbish bags
Mischief (Image by DESIGNECOLOGIST from Unsplash)

So there it is…

Isn’t it shocking to realise ‘biodegradable’ means very little? And ‘compostable’ isn’t always as simple as it sounds either.

But you still have the power to make more eco-friendly consumer decisions. Whether you look more carefully into the materials you buy, dispose of waste more effectively or call corporations out on their BS. ✌

Originally published at https://carolineisawriter.com.

Age of Awareness

Medium’s largest publication dedicated to education reform | Listen to our podcast at aoapodcast.com

Caroline Bunting-Palmer

Written by

Celebrates and encourages the small ethical changes we can all make. 🌿 Freelance blogger and copywriter at https://carolineisawriter.com/. ✍

Age of Awareness

Stories providing creative, innovative, and sustainable changes to the ways we learn | Tune in at aoapodcast.com | Connecting 500k+ monthly readers with 1,200+ authors

Caroline Bunting-Palmer

Written by

Celebrates and encourages the small ethical changes we can all make. 🌿 Freelance blogger and copywriter at https://carolineisawriter.com/. ✍

Age of Awareness

Stories providing creative, innovative, and sustainable changes to the ways we learn | Tune in at aoapodcast.com | Connecting 500k+ monthly readers with 1,200+ authors

Medium is an open platform where 170 million readers come to find insightful and dynamic thinking. Here, expert and undiscovered voices alike dive into the heart of any topic and bring new ideas to the surface. Learn more

Follow the writers, publications, and topics that matter to you, and you’ll see them on your homepage and in your inbox. Explore

If you have a story to tell, knowledge to share, or a perspective to offer — welcome home. It’s easy and free to post your thinking on any topic. Write on Medium

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store