What’s the difference between a compostable and biodegradable products, and why should you care?

Public interest for sustainable alternative products to everyday items has massively increased over the past decade. Garden centres have not been immune to this ideology change.

The “war on plastic” means that there has been a sharp increase in search demand for compostable-related terms in the past two years.

Amongst the most-searched-for Google terms relating to the subject are ‘compostable bags’, ‘compostable cups’ and ‘compostable plastic’. It shows a growth in public awareness and showcases how consumers are actively looking for greener options.

compostableBut whilst the increased interest by the public for compostable packaging is a positive change, there’s still a lot of misinformation out there.

Unsurprisingly, searches for information on compostables and biodegradables has also increased, as people try to understand the differences and choose the best option.

Here, recycling experts First Mile have explained the key difference between compostables and biodegradables, and why it’s important for those working in the gardening industry.

Two different types of products

Biodegradables and compostables are not the same, even though people often get them confused for each other. They are made from different materials, through different processes and, most importantly, have a very different end-of-life from one another.

To be called compostable, packaging with this material must be certified, which means it was officially tested. It decomposes completely like organic matter in up to 180 days, leaving no toxics or residues behind. Compostables are made from renewable resources and, once it breaks down, it works as a fertiliser.

Biodegradables are made of petrochemicals-based materials modified to break down quickly by biological processes (microorganisms such as bacteria and fungi). However, they don’t necessarily include a timeframe for decomposition and doesn’t specify the conditions needed. Because of this, biodegradable packaging often ends up in landfills where they can take years or even decades to break down, releasing toxic gases during this time.

Where does the confusion come from?

One of the arguments often used by the industry is that some biodegradable products are photodegradable (break down when exposed to the sun) or oxo-degradable (reacts to oxygen to break down), and therefore they would be a green option. However, this serves to create a bigger problem as they break down into tiny pieces of plastic that never disappear and don’t offer any nutrients to the soil.

To make things worse, these microplastics will ultimately end up in the oceans, harming marine life and more often than not, entering our food chain. By now you probably got the message: from a sustainability perspective, there isn’t much point in biodegradables.

What you need to consider for compostable products

compostableAlthough it might seem like a good idea to throw compostables into your garden, most compostable items won’t actually break down in your home compost, and also can’t be disposed of with food. That’s because, although they’re able to decompose back into natural elements, they need special conditions – moisture, temperature, pressure, and microorganisms. Home composts don’t meet these criteria – they’re ok to decompose food or garden waste, but not compostable packaging items.

On that note, it’s also interesting to know that your food waste is taken to a different location than compostable waste, since they need different processes. While food breaks down by microorganisms at an approximate temperature of 37 degrees in a local Anaerobic Digester, compostable materials need to spend some time in an autoclave in high-pressure conditions and at temperatures of up to 166 degrees. The good part? Eventually, both food and compostables end up fully recycled as fertilisers, and the green energy resulted from this process is used to heat houses in the UK.

Saying no to plastics is already on everybody’s mind, but we also need to be mindful of our alternatives. There is no simple answer. Yes, compostable packaging is a better alternative than plastic for many everyday products – however, it needs to be recycled correctly (that means not in food waste, mixed recycling or general waste), but in a specialist compostable packaging recycling service.

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