Fast fashion often ends up trashed. New recycling techniques could help.

Sorted used clothes in a warehouse that will later be deconstructed and made into new garments. Photo / the Washington Post

• The fast fashion industry contributes to massive textile waste, with 85% ending up in landfills.
• Recycling is challenging due to blended fabrics and a lack of centralised collection infrastructure.
• Efforts to improve recycling include near-infrared spectroscopy and electrostatic separation to sort and recycle textiles.

Each year, as tens of billions of garments are made, countless unwanted clothes end up discarded – often destined for landfills or incineration.

The fast fashion industry often gets blamed for encouraging people to buy more than they need and for making clothes that don’t last long.

Another problem with all those seasonal must-haves is that recycling textiles can be difficult – especially when so much clothing is made from a combination of fibres.

A key challenge, experts say, is figuring out how to sort and separate materials in a way that makes them usable in new clothing.

“Most of our garments themselves, the majority are not made from a kind of mono-fibre fabric,” said Karen Pearson, chairwoman of the sustainability council at the Fashion Institute of Technology in New York.

“It’s hard to get back to a point of pureness, and how you can treat and refabricate the textile is based on how pure it is.”

But she and other experts said efforts to improve and expand textile recycling are under way.

Why don’t more clothes get recycled?

Out of all the textiles produced, the Environmental Protection Agency estimates that about 85% wind up as rubbish or are incinerated.

Less than 1% of the material used to make clothing is recycled into new garments, according to a 2017 report from the Ellen MacArthur Foundation, a British non-profit focused on promoting a circular economy.

The difficulty starts with collection, said Amanda Forster, a materials research engineer at the United States National Institute of Standards and Technology.

There isn’t a centralised collection infrastructure for textiles in the US, Forster said, noting that it often falls to charities, such as Goodwill, to take in unwanted clothes and figure out what to do with them.

“Trying to make the best decisions about every single individual item in there is a big, big challenge,” Forster said.

A seamstress repairs damaged used clothes. Photo / the Washington Post

Once these garments are collected, recyclers must sort all the material by type – a process complicated by blended fabrics. Sorting and detangling blended textiles, which can be a mix of natural and synthetic fibres, can be costly and time-consuming.

Previously used fibres also aren’t always accepted by textile mills, said Abigail Clarke-Sather, an associate professor of mechanical and industrial engineering at the University of Minnesota Duluth.

Many mills have strict technical specifications about the length and purity of the fibres they will take. Cotton fibres, for instance, typically need to be at least 2.5cm to 4cm long, she said.

“They want the input quality of materials so they know they can get the output quality of yarn, of thread, that can become the output of fabric that their large retailer customers are asking for,” said Clarke-Sather, who researches textile recycling.

How can recycling textiles be improved?

Research is ongoing to make sorting textiles more efficient and accurate.

Near-infrared spectroscopy, which measures how much light passes through or scatters off fabric, is one approach. The method produces a unique pattern that can act as a fingerprint to identify the types of fibres in clothing.

In January, National Institute of Standards and Technology scientists released a database of these molecular “fingerprints” to help recycling centres sort materials more rapidly.

Researchers are also experimenting with using static electricity to separate different fibres. When fibres rub against each other, they can pick up a charge. A natural fibre such as cotton will have more of a positive charge, whereas a synthetic like polyester will become negatively charged.

When exposed to an electric field, the positively charged cotton fibres can be pulled apart from the negatively charged polyester fibres, said Katarina Goodge, a postdoctoral researcher at the institute, who has studied this method.

“It’s using intrinsic properties to the fibres,” Goodge said. “If there is a blend in there that you weren’t able to pick up on during the sorting process, it can still sort that itself.”

While work on electrostatic separation is nascent, Goodge said it could become part of a mechanical recycling system, which involves shredding textiles into fibres.

However, shredding causes fibres to degrade and become shorter over time, experts said. Shorter fibre lengths can affect material performance, leading to issues such as shedding and pilling. Mechanical recycling can also have an environmental cost, in part because the process typically requires energy and water.

Chemical sorting and recycling is another method being studied that can create virgin-quality materials from used fabrics, said Amber Harkonen, circular business manager with Circulose, a brand that makes new material out of textile waste.

Similar to mechanical recycling, chemical recycling at this point can involve some environmental trade-offs: it requires water and heat, and the use of chemicals.

Still, Harkonen said recycling textiles mechanically or chemically can still be better for the planet than making virgin materials “the old-fashioned way”, such as conventionally grown cotton.

Experts are also studying biological processes that use naturally occurring enzymes and could have a “substantially smaller environmental impact” compared to synthetic chemicals, some of which might be derived from fossil fuels, Pearson said.

It’s critical, she and other experts said, to continue developing all available recycling techniques.

“There’s lots of processes that can create usable fibres,” Clarke-Sather said. “The question is are there fibre mills that are willing to accept and innovate and experiment with those fibres?”

The demand for recycled material exists, she added.

“Consumers want to wear recycled fibres,” she said. “They want to do the right thing.”

Allyson Chiu is a reporter focusing on climate solutions for The Washington Post. She previously covered wellness and worked overnight on The Post’s Morning Mix team.