Designing to Biodegrade

Designing to Biodegrade

By Fiona Forrest

Planning for end of life for technical textiles is mandatory in many countries, but now some fashion designers are planning for the end of life of their garments. One method of complete disposal is biodegradation—but is a t-shirt that can biodegrade in just 12 weeks viable, and why would a customer buy such an item?

Why Should We Biodegrade Used Textiles?

A lot of used textiles end up in landfill. Landfills expose these textiles to little oxygen or bacteria, so a garment made from nylon, for example, could take over 40 years to decompose—and it remains where it is.

To reduce this waste, initiatives like the circular economy, where waste is reused in its entirety, mean more recycling of fibers. However, what happens when these fibers also come to their end of life? Recycling isn’t infinite; fibers degrade in quality with each process and eventually become unusable.

However, there is the option of biodegradation. Just like a gardener’s compost heap, material that is biodegraded breaks down its organic compounds with air, water, and bacterial action. The result can be re-used as soil or fertilizer. (It could even be argued that this is “circular” if the resulting soil or fertilizer is re-used to grow fiber crops.) However, for this to happen successfully, the material must be free of all contaminants such as fabric coatings, zippers, buttons or trims. Everything within the garment—dyes, fastenings, and even thread, must be organic and biodegradable if nothing is to be left behind. The composting itself can be an industrial process or more localized, and the use of anaerobic digestion systems can even produce usable biogas, as a by-product from the breakdown of the organic fibers by bacterial action.

What Is the Difference Between Biodegradable and Compostable?

Research by Plymouth University in 2019, showed that the term “biodegradable,” as used by retailers, had no official definition or requirements, often misleading consumers. The term “compostable” means products capable of complete biodegradation in compost, and which break down or completely disappears even when not placed in ideal composting conditions.

However, the researchers found that many “biodegradable” products still persisted in the environment, with minimal degradation of quality, after three years. While consumers may be looking for biodegradable fibers (whether for their own lifestyle choices or in order to follow guidelines), finding truly compostable fibers isn’t simple.

Which Fibers Can Biodegrade?

There is a large range of fibers that can be biodegraded. Most natural textiles, like cotton, wool, silk, or hemp can biodegrade, but most garments are mixed with other materials. If, for example, cotton is mixed with elastane (even a small percentage), it’s no longer classed as biodegradable.

 Hemp will biodegrade in weeks; cotton in about five months; but natural silk can take four years to even begin the process. For bamboo fibers the story gets more complicated. Bamboo linen, made using enzymes to break down the fibers, can biodegrade in about a year; but bamboo rayon, isn’t classed as biodegradable at all. In 2009, a US Federal Trade Commission ruling stated that rayon products are not biodegradable because they will not break down in a reasonably short time after customary disposal.

There are some, more exotic, fibers that can be biodegradable, but only if used without other fibers in the mix. Microsilk is a bio-engineered spider silk, made by Bolt Threads. It’s biodegradable and already favored by designers such as Stella McCartney. Mycelium is a type of fungus, but when used as a leather replacement it is usually combined with a polymer backing, which isn’t biodegradable. Soy is also a biodegradable fiber, although its extensive use of farming land may make it undesirable in terms of sustainability.

 Designing to Biodegrade

One new fiber source is algae. Vollebak, the high-tech fashion brand for outdoor clothing, have designed an algae tee-shirt that biodegrades in just 12 weeks if composted. Vollebak are known for making “indestructible” clothing—so why did they want to make a biodegradable t-shirt?

“There are three ways to tackle sustainable clothing,” Vollebak CEO and co-founder, Steve Tidball says. “You can use advances in material technology to make clothes with a longer life expectancy than the people wearing them. You can start digging into waste and trash streams to use the stuff people have already generated and discarded. Or you can go back to using nature to make clothes that require as little energy as possible and leave no trace of their existence at the end of their lives.”

Why would customers buy a compostable tee? “I think they’re buying into a story around how clothing is made and consumed with new materials,” Tidball says. “And algae is a really important new material to start making clothing out of. It produces 50–80% of the oxygen on the planet, and only needs light, carbon dioxide, and water to grow at high speed. Now, when you start using it to make clothes there are some practical realities that come with that. Algae can’t survive once it’s removed from water, so the algae on the t-shirt is no longer alive. And because it started life as a plant rather than a chemical dye, the natural pigment in algae is more sensitive and won’t behave like color normally does on clothing. As soon as it comes into contact with air it starts to oxidize, which means the green will begin to change color and your t shirt may look different from one week to the next as it fades. But ultimately, you’re going to be able to bury your t shirt at the bottom of your garden. And that’s a really fun story to tell if someone asks you why your t shirt is faded.”

Photos courtesy of Vollebak/Sun Lee

Millions of women (and some men) throughout the world pull on a pair of tights, or pantyhose, as part of their work clothes. While discarded tights can be recycled (for example into wall insulation), this seldom occurs, and instead most will go to landfill. In France alone, 30 million pairs of tights are sold each year (2018) representing over 7000 tonnes of waste.

Co-Founder of Billi London, Sophie Billi-Hardwick, spent 18 months working on the problem of how to get tights to biodegrade within five years. They use a manufacturing formula of nylon, a 6.6 polyamide, modified to attract microorganisms to accelerate its biodegradation process in an anaerobic environment. These bacteria eat the tights, reducing them into organic matter and biogas. The formula which allows this transformation is currently secret.

Photo Credit: Billi London

“The tights are designed in London by my co-founder and I, and are sustainably and ethically produced in Italy by the best experts in luxury fiber,” Billi-Hardwick says. “Like millions of women worldwide, I wear tights for most part of the year and I casually throw away a couple pairs every month. This is a problem, because it is impossible to recycle a used pair of tights into a new one. Each year, 2 billion pairs of tights are produced, worn once, and discarded. And the harsh reality is that tights will take between 40 to 100 years to decompose. So Billi London was born out of our own frustration and realization of how damaging binning two pairs of tights a month is for the environment. The separation of the two materials (nylon and elastane) once combined together is technically impossible so tights made with recycled nylon won’t improve the landfill waste issues caused by the tights industry. Therefore, a laddered pair of tights made with recycled nylon that’s then thrown away, will pollute like any other tights made with virgin nylon and elastane. The problem is that very few are aware of this and when consumers see on tights packaging the mention ‘recycled tights’, most will assume they are made from old tights. But unfortunately, the tights industry is not yet a circular industry, meaning that we can’t produce a new pair of tights from an old one.”

How was biodegradability the answer? “Biodegradability was already an existing and successful solution in the fashion industry, but it was never used in the tights industry. So, for the past 18 months we have been working with fiber experts to bring this innovative solution to the tights industry…we’ve worked hand in hand with our partner in Italy who worked so hard to ensure we could find the correct weaving technique; offering premium, durable, and comfortable, enhanced biodegradable tights. There is definitely a general increase in awareness in how unsustainable the fashion industry is and its impact on climate change. And there are hundreds of studies proving consumers are already operating from a sustainability mindset. Especially since the global pandemic, consumers want to make smarter choices and play their part… knowing that by wearing Billi London tights they can contribute to reducing the time that a pair of tights pollute the environment in landfill by more than 80%, has been a key reason for them to switch from traditional tights to biodegradable ones.”

How Can We Be Sure of Biodegradability Claims?

One method is certification. In January 2021, Asia Pacific Rayon (APR) were awarded the international “OK biodegradability WATER” and “OK biodegradability SOIL” labels by accredited certification board TUV Austria, for APR’s Viscose Staple Fibers (VSF). The tests were carried out by independent research laboratory Organic Waste Systems.

VSF is bio-based, using wood pulp to produce biodegradable fibers. The certification has components that include aerobic biodegradation, and no adverse ecotoxicological effects. The fibers were certified as more than 93% biodegradable within 28 days. APR claims to be Asia’s first fully integrated viscose rayon producer with a capacity of 240,000 tonnes at its factory in Riau, Indonesia.

Using Clothes to Tell A Story

There are more choices than ever for biodegradable fibers—and increasing legislation in many countries also means that putting waste into landfill is no longer an option. Perhaps more importantly, consumers now want more from their garments. They want to tell the story of their clothes. For the Instagram generation, this element of telling a story with their clothing choices shouldn’t be underestimated by the bigger brands. Just as other sustainability issues have directly affected both the output and marketing of fashion, biodegradability is one of many elements that consumers are looking at before making their purchases—while wearing their fading t-shirts with pride.

Fi Forrest is a UK-based science and technology writer and TABBIE Award Honorable Mention winner for AATCC Review’s Space Textiles feature.