Bioplastic

Bioplastic is popping up all over the place, from takeaway tubs to composting bags. The name sounds kind of good (bio), kind of bad (plastic). So what’s the deal with this kind of plastic? Should you be supporting it? How do you dispose of it correctly? And how can you even spot it in the first place?

What are bioplastics?

In a nutshell, bioplastics are plastics made from plant material, rather than oil. Crops such as corn and sugar cane are used to produce cellulose and starch, which are then turned into materials with similar properties to oil-based plastics. A common bioplastic is PLA (polylactic acid).

Unlike oil-based plastics, bioplastics break down into water, CO2 and houmous (organic matter) when composted.

For this reason, they’re becoming a popular material for holding anything you might want to compost – think food waste caddy liners, dog poo bags, takeaway food trays and milkshake cups. They’re even used to make packing peanuts (you can tell which are the bioplastic ones because they dissolve if you run them under the tap).

Are they eco-friendly?

There are pros and cons to bioplastics. On the plus side, they have the same useful properties as plastic (e.g. waterproof, sterile) and they don’t lead to harmful chemicals lurking around in landfill, so they’re much safer to dispose of than oil-based plastics.

On the down side, they’re often still single-use themselves, so there’s the carbon footprint of their production to consider. And because they're plants, they take up field space that could otherwise be used for growing food.

As we’ll see below, disposing of bioplastics isn’t entirely risk-free: they can contaminate recycling streams when put in the wrong bin and, depending on the type, may need to be composted industrially rather than at home.

How do you dispose of them?

Composting

Don’t get caught out: biodegradable and compostable are not the same. You might have seen plastics labelled as “biodegradable”, but it doesn't mean they're a bioplastic. They might just be an oil-based plastic designed to break down into smaller bits of plastic over time (a big problem – see our blog post on microplastics).

Bioplastics not only break down but, most importantly, they break down into compost. Having said that, how you should compost them can vary depending on what they’re made from. Some types will be happy on your home compost heap, whereas others will need to be fed to an industrial composter to have the right conditions to turn into compost.

Recycling

Bioplastics can potentially be recycled, but they currently aren’t being produced in large enough quantities for anyone to provide a bioplastic recycling service.

Plus, it’s easy to get them muddled up with oil-based plastics. Even the optical sorters in recycling plants can struggle to tell bioplastics from conventional plastics. If bioplastics sneak their way into recycled material, it can lead to a poor-quality product that could potentially start breaking down into compost – not what you want from anything that’s supposed to be waterproof. The thing to remember here is to not stick bioplastics in your normal recycling bins.

General waste

If you don’t have a compost heap, and your council doesn’t accept bioplastics, your only choice currently is to put bioplastics in your general waste, where they will either be burned for energy or landfilled.

Here too, the ingredients bioplastics are made from can affect their eco-friendliness. Some types will happily break down into harmless products in landfill, but others will produce methane– a damaging greenhouse gas that the planet could really do without!

How do you know if something is a bioplastic?

Packaging labels strike again! It’s a confusing world, but there are a few symbols you should keep your eyes peeled for. First up, there’s the compostable symbol, or ‘seedling’. Things with this symbol on them can be broken down through industrial composting and can be put in your garden waste bin IF your local council accepts bioplastics.

seedling symbol
The 'seedling' symbol

The other symbol to look out for is the home composting symbol. We won’t go into detail about this; it’s pretty self-explanatory!

home composting symbol

The home composting symbol

Team What Plastic recently received a magazine through the post in a plasticky wrap with no labels on it at all. It turned out that the plastic wrap was fully home compostable, but the label was on a piece of paper tucked inside the package. The moral of this tale is that you should remember to check for labels elsewhere, not just on the plastic itself.

What’s the verdict?

Being eco-friendly is all about doing the least damaging thing, and there’s often a trade-off, as explained above. In terms of reducing waste, avoiding plastic contamination and creating a ‘circular’ process where the only alternative would be single-use plastics, bioplastics are a great solution. But it’s important not to use bioplastics as an excuse to be wasteful. Wherever possible and reasonable, the gold standard is still to opt for reusables and avoid throwaway products.