Degradable, Biodegradable And Compostable: What’s The Difference?

All plastics labeled “biodegradable” are degradable. And all “compostable” plastics are biodegradable. But not all “degradable” plastics are compostable or biodegradable.

Confused? You’re not alone.

You see these terms a lot. And it's hard to know the difference, so you might think that you're doing something eco when you're not.

In fact, last year, a Senate inquiry found that there is widespread confusion about the differences between degradable, biodegradable, and compostable plastic bags. The report recommends that consumers should be made aware of how each type affects the environment and how to properly dispose of them.

With that in mind, here’s our handy guide to help you make sense of those labels.

Degradable

Degradable plastics are petroleum based and have other chemicals (including heavy metals) added. These plastics break down eventually because, well, that’s what “degrade” means. All plastics are degradable, either because they’re intentionally broken down (like if you take a hammer to a plastic cup) or through the natural degradation of the material, which could take hundreds of years. When a label says “degradable,” there’s really no telling how long the plastic sticks around after you throw it away.

Are degradable plastics a greener alternative to regular plastic bags? Unfortunately, experts say they’re probably just as bad for the planet.

You see, degradable plastics don’t “return to the earth”; they just break down into millions of tiny pieces of plastic. That makes them harder to remove from the environment and easier for animals to ingest. Some of the “microplastics” left behind enter the food chain via smaller species like plankton, fish, and birds, eventually making their way into human bellies.

Degradable plastics go into the general waste bin. They're not suitable for compost bins or worm farms.

Don't be fooled by "recycled plastic", either. It's recycled, but it's not biodegradable.

Biodegradable

Biodegradable plastics can be made from sustainable materials, like rice husks, or they can be made from oil. And like degradable plastics, they contain chemical additives that give them certain properties. Here, the added chemicals allow them to break down under the action of microorganisms, usually bacteria.

Like “degradable,” the term “biodegradable” says very little about what happens to a plastic bag when you dump it. After all, everything biodegrades given time.

As with degradable plastics, there’s no way of knowing just how long it takes before a biodegradable plastic bag breaks down completely. There’s no time frame required. Another problem is that there are no restrictions on the toxic residues that these plastics may leave behind. Some biodegradable plastics are better than others, but the only way you know is to ask questions before you buy.

Biodegradable plastics are not suitable for the compost pile. They go into the general waste bin along with the degradables.

Read more: How To Recycle Just About Anything

Compostable

Compostable plastics (also known as bioplastics) are made from renewable raw materials like corn starch and soy protein. Bacteria digest this type of plastic and turn it into compost.

A compostable plastic bag must meet certain requirements to earn its label. For example, it must biodegrade within a specific time frame. It can't leach heavy metals or other harmful residue, can't be toxic to worms, and must be able to support plant life.

Collect your food waste and organics in compostable plastic bags. When it's full, dump the bag into your home compost bin or send it to a local composting facility. Don't put it in the general waste bin, because it won't as compost well in landfill.

Where to buy compostable bags?

Hello Charlie has a full range of certified compostable rubbish bags from trusted brands like BioBag, Wotnot, Biotuff, White Magic and Onya. All of these are great for home composting, dog waste and keeping food fresh. We've even got things like reusable zip lock bags and cling wrap that are all fully compostable.

Image: BigStock