Investigating the effectiveness of biodegradable and compostable packaging

The Citizen Science Home Composting Experiment

By Virginia Neal
January 2021

Most of my work for Minerva over the past three years has involved working on the EU H2020 funded BIOVOICES project.  One of the aims of the project is to raise awareness and increase knowledge about bio-based products and I have discovered that the debate about the environmental benefits of using bio-based products is extremely interesting and quite complex.  There are now so many bio-based products available, from dog poop bags to food packaging, all being marketed to highlight their ‘green credentials’ and biodegradability.  

This all sounds plausible and positive but as a consumer I am concerned about the reality of the situation – whether what I am being sold really will have a positive effect on the environment, or if these products just reflect businesses climbing onto the green bandwagon and effectively greenwashing consumers?

Are these items really home compostable? Do they breakdown with no negative effect on the environment? Are these materials really the answer to our waste crisis or do they just encourage us to use more? Will these items only breakdown under industrial composting conditions? I could go on….

Whilst carrying out some research on bio-based plastics I noticed that University College London (UCL) Plastics Innovation Hub were running a nationwide citizen science research experiment to investigate the role and effectiveness of biodegradable and compostable packaging. It is not often that as a citizen I get asked my opinion, so I decided to participate.

 The first part of the experiment was a short survey to discover what I think of biodegradable plastics, what I do with them, and if I ever home compost them.   As I do home compost my kitchen waste, I was able to move onto the practical part of the experiment where I was asked to place a few biodegradable plastic items in my compost bin, and then report back to UCL about whether they compost or not.  It was really easy to participate. I downloaded the App onto my phone which prompted me to photograph my compost bin and the items that I planned to compost, which I then uploaded.

The items that I buried in my compost bin were a coffee cup made by Nature’s Cup where it was written on the cup that it is 100% compostable and 100% biodegradable; an Enviro Lid which again stated that it is 100% compostable; a Percol coffee pack that carries the TUV Austria ok Home Compost label and a few 100% compostable wrappers from The Guardian magazine.

Having buried the items in the compost and uploaded all the required details to the App. I forgot about the experiment until I was reminded that the required composting time had elapsed and that I should search for the items in my compost bin. I dressed myself in my oldest clothes and started to dig out the compost – an extremely smelly and messy process!

The first items I came across were the coffee cup and lid. The cup had almost completely degraded but the lid was 100% intact with no sign of any breakdown.  The Percol packaging was more difficult to locate as this had broken down to some extent and was quite fragmented.  The Guardian magazine wrappers I retrieved were virtually unchanged with little sign of breakdown, just some discolouration*.

Despite the smell and the mess, I spent a very interesting hour looking at how different things had broken down (or not).  I retrieved quite a few tea bags of the pyramid type, many small labels from bananas and rubber bands from herbs and spring onions that had found their way into the bin. In general, many of the 100% compostable bags and magazine wrappers were still pretty intact. 

The exercise confirmed for me that there is still a long way to go to ensure that as a consumer I can begin to trust the messaging around compostable and biodegradable items. I personally need to feel more confident that the materials I am being encouraged to introduce into my home compost system, that will end up on my vegetable garden and ultimately in my food, are indeed safe. The introduction of additional, often complex materials to our waste system that is not yet designed to cope with them, would seem to be misguided and could result in additional negative effects on the environment. 

However, if the messaging sent out is honest and straightforward, there are opportunities for bio-based products to have a positive impact on the environment.  More research is required about the end-of life options for these materials and the investment in infrastructure required to deal with them before they are made more widely available.

The UCL Big Compost experiment is ongoing and everyone is encouraged to participate.  To find out more visit https://www.bigcompostexperiment.org.uk

*Interestingly, I have noticed that The Guardian no longer uses the ‘compostable’ wrapping for their magazines and have changed to using paper which is widely recyclable through most local authority systems – much simpler.

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