Textile Waste — Resource or Trash?
Focus on end-of-life textile waste options
With the advent of climate-panic almost every brand has refurbished itself in shades of green and talks about sustainability. More and more, we hear about garment and shoes which are made from recycled textile and plastic waste.
Adidas, H&M, Levi Strauss & Co, Nike, The North Face and many other great brends view sustainability hand in hand with innovation. For a number of years, these companies have been looking for ways to reduce their environmental impact, introducing special programs and supporting sustainable innovations.
What is the current situation with textile waste recycling? Should we consider discarded textiles as a resource or waste? How sustainable are clothes from recycled materials? Can these items save our planet? This post will help you to get answers on these questions and learn more about recycling.
Textile Waste Recycling: Briefly in Numbers
World disposes 75% of textiles waste annually due to the absence of viable recycling strategies.
87% of all end-of-use textiles going to landfill and incineration
Only 20% of clothing is collected for reuse or recycling.
Less than 1% of textile materials used to produce clothing is recycled into new clothing.
The rate of recycling clothing after use could be below 0.1%.
About 95% of the recovered fibres are in fact not respun into yarn but are directly processed into nonwovens.
Recycling and reuse of materials is not new to the textile and apparel industry. For centuries, textile products were remade to fit someone else, redesigned to create a more stylish garment or broken down to the yarn stage that was used to produce different fabrics. With the introduction of manufactured fibers in the late 19th century and synthetic fibers in the 20th century, the practice of breaking down post-consumer products and reusing the fabric, yarns, and fibers was reduced due to technical and economic reasons.
Because of an increased awareness of the existing apparel industry impacts, the interest in garment reuse, recovery and recycling is rapidly on the rise. Reuse refers to the utilisation of product in its original form, recovery refers to waste-to-energy conversion processes, and recycling refers to the conversion of waste into a new product.
Textile waste streams comprise pre-consumer (or post-industrial) waste, and post-consumer waste. Pre-consumer waste includes materials generated during industrial processing of textiles by the manufacturer that never reaches the consumers (scraps, damaged or defective materials, samples).
On average, about 15% of fabric used in garment production is cut, discarded, and wasted in the process, which contributes to post-industrial waste.
Post-consumer waste includes end-use of products, such as items returned or disposed by the consumer.
Two main categories of textile waste recycling technologies exist and include, mechanical and chemical approaches, summarized as follows:
Textile waste can be classified into three main groups, which are cellulose fiber, protein fiber and synthetic fiber relating to the textile raw material. Cellulose fiber is made from plant materials such as cotton, flex, hemp and ramie. Protein fiber is produced from animals including wool, angora, cashmere and silk, and synthetic fiber is made from petroleum-based chemicals such as polyester, nylon, spandex, acrylic, and polypropylene.
Each type of raw material needs a specific kind of chemicals in the production process, many garments are made of a combination of synthetic and natural materials, which requires recycling in different ways, and therefore making the recycling process so challenging.
In this post, four major materials are in the focus, including synthetics and naturals: polyester, nylon, cotton and wool.
Intro Polyester has a market share of around 50 percent of total global fiber production and is the world’s most commonly used synthetic fibre. Polyethylene terephthalate (PET) is the most common subclass. The raw material components of PET are generally derived from petrochemicals, with main applications for fibre and packaging production.
Environmental impact The environmental impacts of polyester are significant, with recent studies of microplastic release in aquatic systems.
Recycling Approximately 7% of total polyester fibre production is derived from recycled polyester materials. While the ‘fibre-to-fibre’ process is not that common as of today, the ‘bottle-to-fibre’ process is common practice for polyester bottles. The most recycled polyester fibres are derived from mechanically recycled PET bottles. From 2015, the market of recycled PET spun into yarns from plastic bottles increased by 58%.
Intro Nylon is a widely used synthetic polymer material for various applications including fibre, packaging/films, carpet, and component parts mainly for automotive industry. Nylon-6 and Nylon-6,6 comprise approximately 85% of nylon material used.
Environmental impact Annually nylon production requires more energy to manufacture than polyester and nearly three times as much as conventional cotton. Dyeing nylon is not suited to natural or low-impact chemical dyes and is thereby another contributing factor to the environmental impact from its production process. Nylon derived microplastic pollution in aquatic environments from nylon fishing nets (with total fishing net waste accounting for 10% of ocean waste), and synthetic textile fibres from laundering.
Recycling The closed-loop recovery of Nylon-6 has been widely used in the carpet industry, through combining mechanical and chemical processes. Nylon-6,6 is commonly recycled mechanically from pre-consumer fibres.
Intro Cotton fiber is the most commonly utilized natural fiber in the textile industry. The annual production of cotton fiber is about 26 million tons with the yield about 823 kg per second! Cotton fibres contain more than 80% cellulose, with the remaining constituents which include waxes, proteins, and pectinic substances.
Environmental impact Conventional cotton production process requires large amounts of water both for cultivation and processing (more than 57% of the total water utilisation in the agricultural sector), the use of arable land and agrochemical resources (i.e. pesticides and fertilisers), the extensive use of energy and other chemicals during the rest manufacturing process.
Recycling The mechanical recycling of cotton is well established and is applied to both pre- and post-consumer textile waste, and generally entails the respinning of recycled combined with virgin material, without additional chemicals. The ratio of recycled fibers in obtained yarn does not exceed more than 25%.
Approximately 75% of pre-consumer waste is recycled by reclaiming cotton fibres for lower-grade yarns and nonwoven products for automotive uses, building insulation, furnishings, etc. Comparatively, post-consumer waste is more difficult to recycle because of their heterogeneity and it is estimated that 95% of pos-consumer cotton products are landfilled or incinerated. The recycling rate of post-consumer cotton products is much lower than that of products made of synthetic fibers, such as polyester and nylon.
The majority of chemical recycling processes of cotton is in developmental stage, or close to commercial adoption. The Lyocell and Ionic Liquid processes are two main chemical methods which have been explored and developed to recycle cotton fabrics and produce regenerated cellulose materials, such as viscose or lyocell.
Intro Wool is a natural animal protein fibre that has exceptional physical properties, with the huge advantage that it is biodegradable and is returned to the biomass of the earth. It is easily dyed and requires less washing than other fibres.
Environmental impact Wool production process can entail unethical practices towards animals and has a huge environmental impact due to high water consumption and greenhouse gas emissions. The production of 1kg of wool fabric can take up to 170,000 L of water and causes the same carbon dioxide emission as driving a passenger car 215 km.
Recycling Wool recycling has been practiced for over 200 years, with several options for its reuse, and is considered as one of the most re-used fibres.The relatively long fibre length of wool makes it well suited for mechanical recycling.Wool accounts for up to 5% by weight of total clothing donated for recycling and reuse.
While chemical recycling of wool is not performed, there have been many research developments into recovery processes of keratin from pre- and post-consumer waste wool for other value-added applications.
1. Efficient recycling methods require technologies to manage the various textile waste streams, which includes the characterization, controlling, identification and separation of constituent components (i.e. trims, buttons, zippers, threads), fibre blends, as well as dyes and chemicals from finishing treatments, from which final fibre quality is not diminished.
2. Difficulties restoring the properties of fibres and integrating recycled fibres into garments without comprising on quality. It is known recycled materials have yellowing problems along with decolourization, degradation, contamination and loss of mechanical properties. It can limit the maximum recycled content in the final products, could lead to further processing steps and additional chemicals for reaching the correct material parameters.
3. Difficulties in recycling blended fabrics (i.e. cotton/polyester, nylon/elastane) due to the varied material composition, heterogeneity and interconnection of the fibers.
4. Difficulties with removing dyes, additives and processing agents from textile materials.
5. Economic feasibility compared to the cost of producing virgin fibre.
6. Future recycling technologies must be less polluting and more energy efficient than conventional processes for virgin material production and existing recycling options.
7. Introducing more microfibers from recycled plastic clothing into the wash cycle (at the moment microfibers may be the biggest source of plastic in the ocean; 34.8% of primary microplastic release into world oceans are derived from the laundering of synthetic textiles).
8. Recycled synthetics are still not biodegradable and will still end-up in the landfill. It does not prevent plastic to enter the waste stream, they just postpone it.
9. Necessity of facilitating logistical support to increase volume of material collected and processed for widespread commercial adoption.
10. A change of the trend in textile waste generation is unlikely without a change in consumer behaviour.
There are many challenges and opportunities facing the industry with regard to environmental sustainability. It is evident that there is a strong need to further develop recycling strategies for textile industry. A viable, ecofriendly concept should allow quantitative and ‘‘green” recycling of all material components without the generation of additional waste streams, or an increase in energy consumption resulting from complex processing steps, keeping all processes in framework of sustainability.
As an example, potentially biochemical recycling process could be an environmentally friendly alternative tool towards the reduction of textile waste. Such recycling processes are highly material selective and work on lower temperatures, enabling a more economic and ecological recycling process of blended textiles.
We all probably know that pollution is a huge and a logical approach to diverting existing textile waste streams is the adoption of textile recycling technologies…
However, recycling isn’t enough on its own and should be only used as part of a wider circular, reusable mindset.
References:
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Liu W., et al., Eco-friendly post-consumer cotton waste recycling for regenerated cellulose fibers. Carbohydrate Polymers. 2018; 206: 141–148 (DOI: 10.1016/j.carbpol.2018.10.046)
Pensupa N., et al., Recent trends in sustainable textile waste recycling methods: current situation and future prospects. Top Curr Chem (Z). 2017; 375:76 (DOI: 10.1007/s41061–017–0165–0)
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Quartinello F., et al., Highly selective enzymatic recovery of building blocks from wool-cotton-polyester textile waste blends. Polymers. 2018; 10(10): 1107 (DOI: 10.3390/polym10101107)
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A new textiles economy: redesigning fashion’s future. Ellen McArthur Foundation. 2017. https://www.ellenmacarthurfoundation.org/publications
Textile recycling technologies, colouring and finishing methods. Katherine Le, UBC Sustainability Scholar. 2018. https://sustain.ubc.ca/sites/sustain.ubc.ca/files/Sustainability%20Scholars/2018_Sustainability_Scholars/Reports/2018-25%20Textile%20Recycling%20Technologies%2C%20Colouring%20and%20Finishing%20Methods_Le.pdf
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