Exploring the compostability of textiles.

Degradability is a contentious subject, especially in textiles. There is a significant amount of greenwash coming from brands, I think because there simply isn’t the understanding of what it means and what it looks like. The visuals are especially important.

Some fashion brands are claiming “biodegradable” on their labels, however this is being confused with “compostable”, even for garments that use synthetic dyes.

So what do these terms mean?

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Degradable

Capable of being degraded - broken down - whether chemically or biologically. Most definitions of “degradable” consider this mostly in regards to chemical degradability, so decomposition from the action of chemicals. The item in question would then degrade [back] into its chemical composition i.e. as polymers (and monomers).

Biodegradable

Capable of being broken down by the action of living things i.e. microorganisms. The definition of “biodegradable” generally also states that the item degrades into innocuous products, meaning harmless or non-toxic.

Compostable

Synonymous with solid matter, rather than liquid, compostable refers to a product that can be placed into a composition of decaying biodegradable materials, and that which eventually turns into a nutrient-rich material. Compost is a mixture of ingredients used to fertilise and improve soil health, and is organic matter rich in plant nutrients and beneficial organisms. So for a product to be “compostable”, it requires the evidence that it will break down in a composting system and be beneficial. Liquids cannot necessarily be compostable, as compost comes into being through solid matter like vegetable scraps and plant waste.

Commercially compostable

This is where a visual understanding of composting systems helps. Unfortunately, products with “commercially compostable” labelled on them cannot be put in a home composting system. What you use for your garden is an aerobic system, which utilises oxygen-requiring micro-organisms to break down the matter, while industrial composting facilities are anaerobic, which use bacteria not requiring oxygen.

The materials stated as commercially compostable, usually made from sugars and starches i.e. corn and sugar waste, such as coffee cup lids and cutlery, require a perfect balance of heat, moisture, and oxygen to break them down - the anaerobic system. What remains after this degradation is a sludge (typically still requiring aerobic compostion) and methane biogas that is helpfully siphoned off for use as “renewable” energy.

Seeing composting in situ aids in recognising how long materials take to degrade if they are in the incorrect system, and how much value is lost because of this. For example, a coffee cup lid designed for commercial composting, yet placed in a home composter, could have degraded into small pieces after a year, but any beneficial impact from this is unmeasurable and frankly unusuable. The same goes for clothing.

*Note: the above image shows these commercially compostable items in an aerobic composting system, and at this point in time, wasn't even a "hot" compost (>60?c). These items are designed for an aerobic composting system where there is no oxygen, so in theory, yes, they do degrade. But the point here is that citizens put them in the compost expecting them to break down.

Natural

Natural fibres are those that come from plant and animals (or minerals, in the case of graphene). As they are, they are both biodegradable, and would aerobically compost. The time frame would differ depending on the fibre type, whether it is spun into yarn or woven/knitted into fabric, and if it has any biological dyes or coatings applied to it.

If a natural fibre has been altered with the use of synthetic components i.e. finishes, coatings and dyes, then it will no longer be biodegradable, if we use the definition above that asserts the degradation of biodegradation is non-toxic. It is important here to note that some colourations and finishes can come from plant sources and are therefore not classed as synthetic, though may still be harmful in enough quantity.

Synthetic

Synthetic, or artificial, fibres are those that come indirectly from fossil fuels, through polymerisation. Man-made natural fibres are generally included in this category because they require chemical components in order to make the natural raw material have specific properties e.g. viscose (rayon) comes from wood pulp, though requires solvents to extrude it as a usable fibre.

Synthetic fibres are degradable, though it is said polyester will take 1000 years to degrade fully. During this time, chemical substances will have leached into soil and water, or broken down as harmful gases.

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Exploring compostability.

During my MA Fashion and the Environment, I investigated design-for-disassembly, and the Cradle-To-Cradle methodology of “biological cycles” and “technical cycles”. Within this, I adhered to monomateriality - so producing garments that used only natural or only synthetic materials and components. The garment would then biodegrade or be recycled (I’ll come to recyclability in another post…), or ideally be able to be repurposed in its own cycle before eventually coming to its end of life.

One garment that had been designed for this process of composting, was a linen and cotton dress. Unfortunately, it took me many years to access a compost system due to my living situation (no garden), and so the garment only went in for degradation in November 2021.

You could simply put a piece of fabric in the compost and record how long it takes to break down, though I was designing clothing that would be worn first. In hindsight, it wasn’t the best aesthetic, but I was combining craft techniques and materials to invoke a feeling of familiarity (as part of the overall MA thesis), and consequently the garment had a mixture of raw edges, braids, metal hooks, ombré dyeing and seam binding.

Construction techniques:

• Raw edges and visible construction = ability to repair and alter if you can see how something is made
• Seam binding = highlighting how the garment was constructed
• Layering = multiple layers gives the option to wear the garment multiple ways, or discard one part if it is damaged

Materials:

1. reclaimed organic cotton poplin
2. reclaimed undyed plain weave linen
3. naturally dyed reclaimed organic cotton yarn - dyed with gall nut/blackberry, and with found weeds dandelion and nettle
4. reclaimed brass picture hooks
5. GOTS certified organic cotton sewing thread

The concern here was the traceability of the organic cotton poplin - was it certified (if not, harmful substances could leach out during the decomposition), and the impact of the brass hooks (metal undergoes lots of processing to make it usable). So though these are all natural materials, chosen for their minimal impact, there could still be a negative impact in the compost.

Due to the size of the compost bay in proportion to my garment - and not thinking of it at the time - I had not undergone any scientific analysis in terms of soil pH for instance, to address whether it had a negative or positive role for the composted matter. My main focus was to see how long it took for the garment to fully decompose in this natural kitchen garden composting system.

I originally wrote this article in January 2022. Come April 2022, when we next were able to turn the bay, it had completely disappeared, even though it had been winter and our compost wasn't particularly hot.

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Additional resources:

I had the pleasure of speaking with designer-researcher Cassie Quinn, for the educational platform The Sustainable Fashion Collective. I actually hate to pass you on to this business after I was unethically dismissed, and it's also behind a paywall (I should've save the unlisted YouTube links). However, it post the link for credibility of the below quotes.

In our conversation, Cassie explains the above terms and issues in this sector, along with thoughts on terms “biomaterials” and “biodesign” to help designers recognise how they can actually put these approaches into practice.

Biodesign started in architecture, with living walls and growing materials to create spaces. / They are living organisms - so oftentimes you will give the exact same environments and not change anything, but they will grow completely differently. / ... with something like algae or mycelium - they respond to their environments, so it's just learning the characteristics of the material."

"There is so much contention around these words and terminologies and it's because there is just no legislation. The fact that you can say something is biodegradable when it can actually sit and last for 1000 years - technically you can, by law, do that."

Watch the interview here.

"The end-of-life management of waste is a huge and complex problem that sits at the interface of the biosphere and the technosphere. We must find alternative pathways for handling the myriad of natural and synthetic materials embodied in the products we consume," ~ Savanna Browne-Wilkinson of Metabolic Institute.

The Biomimicry Institute, a US not-for-profit organisation, is launching a two-year initiative called "Design for Decomposition” to demonstrate scalable new pathways for the 92 million tonnes of fashion waste discarded annually. It comes as a follow up to their The Nature Of Fashion report from 2020.

Read the report here.

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Originally published on my website www.stephaniesteele.co.uk on January 15th, 2022.