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Can recycled cotton make fast fashion sustainable?

Learning more about recycled cotton and cutting through the media greenwashing on this topic has been on my list of things to do since March of 2018 when I met Kristy Caylor of For Days at SXSW. And, with recycled cotton in the news recently I thought it was time to learn more.

But, before we get started

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    You may have heard of Caylor, she is one of the OG’s of the sustainable fashion movement and a crucial player in the success of the brick and mortar store Maiyet back in 2011. For Days uses a subscription model where members can buy t-shirts and once they no longer want them anymore, are able to send them back for new ones. For Day’s then breaks down the shirts, recycles them, and uses the recycled cotton to makes new ones. The entire system is closed-loop. So, there is no waste.

    And, what is really smart about the idea, is that eliminates textile uncertainty that typically prevents fabric recycling from scaling (you'll learn more about that later in this post). Recycling textiles isn’t as easy as recycling plastic or paper. There can multiple fibers in a shirt, and dyes and textile finishes further complicate the process. No one has really been able to figure out how to handle (at scale) the complexities of clothing recycling. But, For Days, with their membership plan knows exactly what and how they are making their shirts, therefore, breaking them down to make new shirts becomes a much easier task.

    recycled cotton fabric for days shirt

    Excited for this For Days basic to become available

    does it scale?

    Caylor's understanding of the industry, it's limitations is impressive. Sadly I often feel like when I hear about new technologies my first thoughts are, well, after working ins fast fashion mills and factories here are 5 reasons why this idea will never scale. I thought her idea was smart. For Days was able to get a ton of press and raise a lot of money. But, it's August of 2019 and they still are not open for business yet. Which makes me wonder, is the technology scalable even in a system with the most stringent of control? I hope it is. If I was a betting woman, I would put my money on For Days to be first to market with a scalable cotton textile recycling system.


    infinity hoodie with recycled cotton

    Stella McCartney x adidas INFINITY HOODIE - image:

    Then, a few weeks ago Stella McCartney and adidas came out with their circular sweatshirt the "Infinite Hoodie” using Evernu’s NuCycl technology and fibers. The media went wild. I was skeptical. I did not trust how most news outlets described the process as if it were some sort of alchemy. Sweatshirts go in, are liquefied, and, alakazam, new fibers come out. Yea, it sounds like magic when put like that. But, basically, that is the process of making rayon. Cellulose, in this case, cotton, goes in. Often times caustic, chemicals break the cellulose down into liquid form. And then, through the process of extrusion, we get new, synthetic fibers. This isn’t exactly new technology.

    But then, (almost like Sangeeta Singh-Kurtz read my mind) Quartzy hit us all with the real facts. Like, only 60% of the sweatshirt is made out of the recycled cotton NuCycle fibers. 40% of the fiber content was actually virgin organic cotton. And, they only made 50 shirts total. Which basically translates to, no, this technology is not ready to scale yet. And, Singh-Kurtz let us all know that before the Stella x ADIDAS partnership Evernu had a partnership with Levis. And, unfortunately, Levis was only able to use 20% of the NuCycle material before they ran into quality issues.

    Hmmm, feels like the technology isn't quite ready yet to change the world.

    Can we trust Stella McCartney?

    Stella McCartney has always stretched the truth and in my opinion been more talk than action. For example, they never got around to making a public statement confirming or denying the burning of their inventory. And, the “Daily Mail reports that her luxury sportswear line with Adidas is actually made in Indonesia by workers who earn on average £188 a month. That is equivalent to 98p an hour if they work 48-hour factory week.” Is that ethical? Not in my opinion.


    H&M 2019 conscious collection campaign

    H&M 2019 conscious collection campaign

    It’s not just high-street that wants cotton alternatives and more circular approaches to supply chain management. Fast fashion is vowing to make changes too. In April, H&M announced they would use only 100% sustainable cotton by 2020 and 100% recycled or sustainable materials in all garments by 2030. But, what exactly qualifies as “sustainable”. H&M goes onto to explain “the company aims to produce clothes out of previously used materials or those that can have an indefinite life after their initial use.”

    Zara, another fast-fashion behemoth, just came out with a statement in July that all of the cotton, polyester, and linen in its line will be organic, sustainable, or recycled by 2025. What is interesting is that Zara’s definition of sustainability is a little different and in my opinion a little more vague “prioritizing more energy- and water-friendly processes in the growing and manufacturing of these textiles.”


    At first glance, these closed-loop systems sound great. Could they be the solution that the fashion industry desperately needs? They promise to allow us to continue consuming at our current rate without burning through the earth's resources. Fast fashion can have their cake and eat it too. Well, in my experience when things sound too good to be true, they usually are.

    So, I did a little more digging with the help of my new intern Emily to find out what exactly cotton recycling is and if it was all just hype and greenwashing, or an actual sustainable solution that could help the fashion industry correct its wasteful ways. Here is what we found out.


    There are three types of processes available to recycle textiles, cotton included: mechanical, chemical and thermal. The most common are mechanical and chemical.


    recycled cotton yarns and clothes

    Image: Sourcing Journal

    Mechanical cotton recycling uses mechanical systems and abrasion to break down fabrics back into fibers. Zero chemicals are necessary.


    mechanical cotton recycling


    Waste from cotton production, post-industrial textile waste, and old clothing from donation collections goes through sorting and cleaning processes. The recycling facility will group textiles by fiber type (in this case we only really care about cotton) and color (this is important later on) and use cleaning agents to prep them for recycling.


    Sorters remove foreign components, like buttons, zippers, and that $20 you left in your jean pocket, etc so only the textiles are left.


    Mechanical shredding reduces the textiles into its smallest fiber state, kind of like a giant blender. This is where color sorting becomes important. If all of the cotton textiles that go into the shredding machines are blue, the fibers that come out are going to be blue.


    The fibers are then re-spun in a blend with virgin cotton or other material (usually polyester) into yarn. Virgin cotton or synthetics are necessary to add strength.

    Again, if the fibers that went in were blue, the fibers that come out are blue, which means the yarns too, will be blue. The yarn can then be dyed a darker blue. In dying you can go from a light color to a darker color, but never the other way around. Or, the mill can try to bleach it lighter before dying. But, remember bleaching and dye processes will degrade the strength of the yarn further.


    The yarn is woven or knit into new fabrics.


    • Inexpensive
    • No chemicals
    • Well-established process


    • Because the mechanical process is extremely rough on the cotton, the fibers lose their strength during the process. This leads to lower quality yarns and textiles. This is why many cotton recycling manufacturers blend in virgin or synthetic fibers, to add strength.
    • Color. If color fibers go in color fibers will come out. This limits the dye houses who are willing to work with the fabric. Generally, dye houses want PFD fabrics (prepared for dye). PFD fabrics are white from a very low concentration bleach treatment. Think of it this way, it would be really difficult to tie-dye a black shirt, but a white shirt will show the colors well. The same goes for commercial, mass production dye facilities – the whiter the textile the easier it is for the dye house.
    • Right now this system does not work on blends. The textiles that go in, need to be 100% cotton


    The chemical recycling process breaks down the cellulose by dissolving it in chemicals and then uses one of two methods to make new synthetic fibers. The two available processes are The Lyocell process, and the Ionic Liquid process.


    The Lyocell method produces regenerated fibers by “processing the dissolved pulp (cotton waste) and blending with other plant-derived pulp products (wood, flax, hemp, etc.).”

    This process was originally developed in the US circa 1970 by Enka Organization under the fiber name "Newcell". And after a few corporate acquisitions and mergers, in 2000 the technology became part of the Lenzing's holdings. While cotton recycling is just making headlines now, the technology itself is nothing new.

    And remember, Patagonia has been using recycled plastic bottles to make new recycled fibers since 1993. That's almost 30 years ago. Another example of old textile technology finally becoming public knowledge.

    Interestingly, as of 2014, in China (Shanghai Shuanglu Chemical Fiber Co.) and South Korea (e.g. Hanil, Hyosung) both companies have been developing a similar process. Sadly, these processes are not scalable, yet. But, I am excited to see what the future holds for them. 

    To break it down, literally and figuratively: The Lyocell process


    Only 100% cotton textiles can go into the lyocell system.


    Pieces of fabric no larger than 10mmx10mm are cut manually.


    In this step, the fabric is broken down through mechanical abrasion into a pulp.


    NMMO (Nmethylmorpholine N-oxide) is added to the pulp.


    The above chemical reaction will dissolve into a 9% cellulose, 14% water, and 78% NMMO solution.


    The process of dehydration removes water from the solution.


    The solution extrudes from spinnerettes to make fibers.


    Fibers are spun into yarns.


    Fiber washing removes any excess chemicals.


    The fibers dry at about 60 degrees Celcius, that's 140 degrees Fahrenheit!


    Weaving or knitting into fabrics.


    • The fibers are about the same strength as virgin cotton and sometimes have better and longer-lasting properties.
    • The solvents are non-toxic and recycled in a closed-loop system. Which means, there should not be issues with local groundwater contamination.


    • 100% cotton only, no blends
    • The process uses a lot of water
    • During the chemical recycling process, the pre- and post-consumer textiles must first be sorted by color and fiber content, the same as mechincal recycling. This is an expensive part of the process because, to date, this step is done by hand. Each fiber content label must be read by a person, and the textile sorted into the correct pile.

    chemical cotton recycling



    Established in 2013, can combat fiber blends.


    Textiles are collected. But, they do not need to go through a sorting process.

    STEP 2: PULP

    Like the lyocell process, the textiles are made into a pulp.


    There are two ways of doing this.

    “Researchers from Aalto University and the University of Helsinki who developed the Ioncell-F process, applied the ionic liquid solvent, [DBNH]OAc (1,5,diazabicyclo[4.3.0]non‐5‐enium acetate) to chemically recycle cotton waste and produce MMCs, with the fibres exceeding tensile strength of native cotton and commercial MMC fibres.93 Researchers from Deakin University demonstrated the use of ionic liquid, 1 allyl-3-methylimidazolium chloride (AMIMCI), to separate cotton from a polyester blend (50:50 polycotton blend). While still in the developmental phase, it has the potential to produce 100% recycled cotton product, but may also be blended with other pulp product to produce regenerated cellulosic materials.”


    The insoluble fibers like polyester and nylon are easy to collect and remove. While the dissolved cotton will remain behind in the solution.


    The 100% cotton solution becomes fibers, yarns and then fabrics, similar to the lyocell method.


    • The chemicals (organic salts in liquid form) are non-toxic
    • Textile recycling is possible with both 100% cotton and cotton blend fabrics
    • The new yarns are as strong and sometimes stronger than virgin cotton
    • The process is repeatable, so textiles will never need to end up in a landfill again


    • The technology is not scalable, yet. And, has only been proven to work in 50/50 blends.


    This is probably the least popular option. Thermal recycling burns clothing to create new energy. Many brands (like Burberry) have recently gotten a lot of bad press for burning their inventory. But, contrary to what the press wants us to believe, thermal recycling is not a bad solution. For more information on thermal recycling check out this article in The New York Times about how trash in Sweden does everything from powering busses to heating homes.

    Wouldn’t it be even more sustainable to power mechanical and chemical recycling processes with thermal recycling energy? But, to do this the industry would have to re-position the negative stance on burning inventory. Maybe, just maybe it could be possible to burn inventory in the name of sustainability? What do you think?


    Don’t get me wrong, it’s fantastic that garment and textile waste are being recycled. But, there are still a lot of pieces to this puzzle that we need to dive deeper into.

    Which is more sustainable? Organic or recycled cotton?

    Let's go back to Stella McCartney for a second.

    Whatever happened to Stella’s vegan spider silk by Bolt Threads? Which, like NuCycle, the media initially loved, but then started to question. Like, what’s so bad about silk? It’s natural. It’s biodegradable. It does not take chemicals to make. Yea, the processing of silk fibers is not that eco-friendly. But, that’s kind of an easy fix. And, that’s exactly what Everlane and Eileen Fisher did with their clean silks.

    As the industry began to demystify Microsilk, they realized it might not actually be more sustainable than silk. Here is a quote taken directly from Bolt Threads website about the process "We extract the liquid silk protein and spin it into fibers in the same way fibers like acrylic and rayon are made."


    Then, brands like Everlane and Eileen Fisher came up with their own practical green solutions to their silk supply chains. They were basically like we see your flashy proof of concept tech of the future, but we are going to create change now. And, so they did.

    It's interesting how sometimes new tech that isn't even in the market yet can push the industry to make realistic changes. It's like this weird game of supply chain tug of war.

    Knowing that story, my first question about recycled cotton was could regular old organic cotton actually use fewer resources than recycling? What is the comparative environmental impact of textile recycling? Could it be that textile recycling (because of all the chemicals and energy) is more harmful to the planet than just planting new virgin cotton?

    Mechanical recycling

    A 2016 project commissioned by H&M concluded that mechanical cotton recycling is less environmentally damaging than new cotton production, especially when it comes to water use, CO2 emissions and fossil depletion. We would like to point out (which the project author does, too) this was not a peer-reviewed study assessing for bias, methodology flaws and/or conflicts of interest (red flag). While the information seems legit my intern Emily was quick to remind me to take this study at face value, especially since H&M is footing the bill.

    Also, the environmental impact depends on where the production facility gets its power from. Are they using fossil fuels to power the facility or more eco-friendly power option - like, maybe, from thermally recycled textiles or other types of trash?

    But we need to think even broader. While the mechanical recycling process appears to have a lesser impact on the environment, we still need to account for the collection and allocation of the clothing and waste materials.

    Unfortunately, it’s still up to the consumer to get her old clothing to textile recyclers And, the planes, trains, and automobiles that transport these fashion rejects need fuel, which gives off emissions. In the future, we would like to see these types of numbers included in textile recycling studies.

    Chemical recycling

    To date, we have not found a clear study that determines if chemical recycling is actually more eco-friendly than organic farming. If anyone knows of a study, please share!

    Is the process of cotton recycling ethical?

    After textile waste arrives at the recycling facilities, actual humans in both mechanical and chemical recycling, have to manually sort through each piece and separate it by fabric composition (and sometimes color) before processing.

    What are the working conditions like? How about the workers pay? Is their adequate ventilation in the facility? Or, are they developing respiratory conditions that are infamous in textiles workers who breathe in fibers regularly?

    To solve the problem of people, Fibersort is a relatively new company (2018) that has an innovative automation sorting process using lasers to sort textiles! Isn’t it interesting how the industries solution to treating people fairly is always to simply eliminate them and replace them with machines? Fibersort is receives funding from Valvan and Circle Economy with ties to Worn Again, another chemical recycling textile company.

    Water use

    Does recycled cotton use less water? While mechanical recycling is low on water usage, the fibers that come out of the system are weak. That mans mechanically recycled cotton needs blending with virgin cotton or synthetic fibers for strength.

    So, we need to remember that this system is not totally closed-loop. New virgin fibers must be added to the loop constantly. And, to make new cotton material, you need a boatload of water for irrigation, and depending upon the type of cotton (organic vs. not), toxic pesticides.

    The Lyocell chemical recycling process itself also requires a sizeable amount of water, but definitely less than growing new cotton. For perspective, to make a pair of jeans made of conventional cotton (from grow to shelf), it takes anywhere from 2,800 – 4,900 L of water. For Lyocell jeans: 1,200 – 1,900 L. In both processes, the growth of the cotton and wood, respectively, is what accounts for the majority of water use.

    Are recycled cotton fibers healthier than organic?

    Technology feels counterintuitive. To think, heavily chemically processed synthetic fibers are more sustainable than naturally grown organic ones.

    But, I guess that is a sign of the sci-fi times we now live in. One where tech is more sold as better for the planet than ancient systems.

    Several companies are trying to bridge the gap between science and going back to the basics. As mentioned before the Ioncell process, uses organic salts. And, Evrnu claims to use 98% recyclable chemicals in their process. But, this sounds like tricky wording from Evrnu. Recyclable does not mean safe for humans. It just means it can be used again. Worn Again, another chemical-process cotton recycling companies work with H&M as well as Kering Group (which owns brands like Gucci, Saint Laurent and Bottega Venetta, to name a few).

    Sadly, no word from Evrnu or Worn Again after an inquiry to the chemical toxicity and disposal methods used in their processes…

    But, Harald Cavalli-Björkman of Re:newcell in Stockholm (founded by companies including Lenzing AG (behind Lyocell) and H&M) was kind enough to reply to Emily’s email about the chemicals in their process.

    “…they are eco-friendly and either recovered or neutralized as part of the process. Our process water is sent to the municipal water treatment plant as household grade waste-water. It is very important for us to comply with strict Swedish and EU environmental regulations concerning chemicals and emissions to air, ground, and water.”

    Our recommendation - REDUCE, REUSE, RECYCLE

    Do you remember when you were a kid, the recycling mantra we all learned: Reduce, Reuse, Recycle? Recycling is the last step.

    In 2008, the EU introduced the 5 R’s of Waste: Refuse, Reduce, Reuse, Recycle, Rot. If we recycle cotton textiles, we are at the second to last stop on the waste wagon. While recycling is flashy (and making companies a ton of money), to make a real impact we need to focus on the first three. Refuse – say no to begin with. Reduce – useless when you can. Refuse – keep using it until you can’t any longer. Then, and only then can we move to the fourth step of recycling.

    It is critical we keep refuse, reduce, and reuse in mind and not look to recycling as a magical cure for our overconsumption problem.


    There is no slow down in the world's consumption, especially with emerging middle classes in developing countries like India and China. But, at the same time, as the world demands more stuff, we all want that stuff to be made with the lowest environmental footprint possible. And, slowly, the fashion industry is responding.

    Even though we feel good when we recycle, is recycling really the best option for making an environmental impact? The jury is still out.

    Is recycling better than the landfil? Absolutely.

    But, the conclusion I keep finding myself coming to is fast fashion is the problem. And, we all need to buy less stuff, instead of looking for loopholes and technology that will allow us to continue consuming at the same rate.

    Cotton recycling is great for helping to deal with the mess we are currently in. But, it might not be the best long term solution if it encourages people to keep buying as fast as they can.

    Researched by Emily Thomas

    What do you think? Did we forget any cotton recycling companies? We want to hear your opinions!


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