Biological recycling uses enzymes to break down fabric and separate it into the component materials

Biological recycling uses enzymes to break down fabric and separate it into the component materials

Two exciting technical developments have been achieved in the recycling of post-consumer apparel of mixed or unknown materials into new fabrics and yarns – in what is being described as a major breakthrough in the journey towards a closed loop for textiles.

The new technologies are the biological breakdown of post-consumer apparel of mixed materials, and the hydrothermal (chemical) treatment of post-consumer apparel of mixed materials. They have been developed as part of the four-year Closed-Loop Apparel Recycling Eco-System Program between the non-profit H&M Foundation and The Hong Kong Research Institute of Textiles and Apparel (HKRITA).

Both methods feature self-separation of the materials, cost effective treatment processes, and eco-friendly treatments – and, importantly, the solutions manage to recycle blend textiles into new fabrics and yarns without any loss of quality.

"For too long the fashion industry has not been able to properly recycle its products," says Erik Bang, program manager at H&M Foundation. "This very encouraging breakthrough on separation and recycling of textile blends has the potential to change that.

"It is the customers' collecting of old garments that have enabled this important research led by The Hong Kong Research Institute of Textiles and Apparel. We are very excited to now start to scale-up this technology and prove commercial viability."

Set up a year ago, the partnership is backed by EUR5.8m (US$6.5m) in funding and aims to find at least one ready technology to recycle clothes made from blend textiles, within the four-year project period.

The focus is on apparel and textile products made from blended fabrics because they account for a high proportion of all products on the market today – yet there are no commercially viable separation, sorting, and recycling technologies for many of the most popular materials, such as cotton and polyester blends.

While it is possible to mechanically recycle single fibre fabrics such as denim jeans and wool sweaters, garments are very often made from a blend of different fibres to improve fit, style, comfort and longevity.

Used apparel of blended or unknown materials currently end up either discarded in landfills, or downcycled into insulation, carpeting, and other low value applications.

Fibre-to-fibre recycling

Teaming up with Ehime University and Shinshu University in Japan has enabled HKRITA to develop a hydrothermal process to fully separate and recycle cotton and polyester blends.

The recovered polyester material can be reused directly, without any quality loss. The hydrothermal process is eco-friendly in that it uses only heat, water and less than 5% biodegradable green chemical, to self-separate cotton and polyester blends.

This fibre-to-fibre recycling method is cost effective, and there's no secondary pollution to the environment, ensuring the life of the recycled material is prolonged in a sustainable way, the research institute says.

Edwin Keh, chief executive officer of HKRITA, tells just-style the breakthroughs achieved are the self-separation of the used fabric materials, 'fibre to fibre' reuse of most of the materials with little to no deterioration of the performance characteristics of the used materials, and a very cost-effective overall recycling process.  

"This hydrothermal technology for the first time makes post-consumer recycling of apparel commercially viable, while maintaining most of the value and performance characteristics of the used materials," he explains. "This not only removes most of the logistics barriers to moving materials, but also for the first time makes repeated "closed loop" reuse of materials possible."

The second process is biological recycling using enzymes to break down fabric and separate it into the component materials. "As only enzymes are used in the process it is energy efficient and eco-friendly," Keh adds. A similar process was pioneered by HKRITA two years ago to turn starchy food waste into polyester.

"By being able to upcycle used textiles into new high value textiles, we no longer need to solely rely on virgin materials to dress a growing world population. This is a major breakthrough in the pursuit of a fashion industry operating within the planetary boundaries."

Commercial scale

Next, the technology will be scaled up and tested further to prove commercial viability. When finalised, it will be licensed to the global fashion industry to ensure broad market access and maximum impact.

"A factory site is already secured and will be ready for operations in a few months," Keh tells just-style. "We expect to be operational by spring 2018.

"This facility aims to process used apparel into yarns, with a planned daily output of close to 3 tons of new yarns at capacity. When completed this may be the first yarn mill to be built in the city of Hong Kong in more than half a century."

The research is also funded by the Innovation and Technology Fund of the Hong Kong SAR Government, with the total project investment estimated at around EUR30m during the four-year collaboration that runs until 2020. This makes it one of the biggest and most comprehensive efforts ever for textile recycling.