Textile recycling
Textile recycling is the process of recovering fiber, yarn or fabric and reprocessing the textile material into useful products. Textile waste products are gathered from different sources and are then sorted and processed depending on their condition, composition, and resale value. The end result of this processing can vary, from the production of energy and chemicals to new articles of clothing.

Due to a recent trend of over consumption and waste generation in global fashion culture, textile recycling has become a key focus of worldwide sustainability efforts. Globalization has led to a "fast fashion" trend where clothes are considered by many consumers to be disposable due to their increasingly lower prices. The development of recycled technology has allowed the textile industry to produce vast amounts of products that deplete natural resources. Textile recycling techniques have been developed to cope with this increase of textile waste and new solutions are still being researched. Recently, certain clothing retailers have embraced this recycling effort and now publicly advertise products that are made of recycled textile material in accordance with shifting consumer expectations.

Starting material 
Most materials used in textile recycling can be split into two categories: pre-consumer and post-consumer waste.

Pre-consumer waste 
Pre-consumer or post-industrial waste consists of textile waste produced at the industrial stage of the production of textile material. Typically, these byproducts are produced by the textile, garment, cotton, and fiber industries and are repurposed by the furniture, home building, automotive, and other industries.

Post-consumer waste 
Post-consumer or waste consists of discarded garments or household articles made from manufactured textiles. These unwanted articles are typically worn out or damaged. Some post-consumer waste is directed towards second-hand retailers to be sold again. Some of this waste is collected in municipal collection bins, but the majority of this waste is found in landfills.

The clothing brand The North Face introduced a program called “Clothes the Loop” in 2013 that allows consumers to recycle post-consumer waste from any brand at any of their retail locations across the United States. This mirrors similar services by charity organizations such as Goodwill Industries and The Salvation Army in the United States. Across the globe, charitable organizations and businesses such as thrift stores have created specially marked collection bins that allow the public to dispose of post-consumer waste so that it can be reused and repurposed.

Processing

Sorting 
When recycling post-consumer textile waste, the sorting process is represented as a pyramid model in terms of the volume of material. At the base of the pyramid - and largest volume - is crude sorting, followed by exportation of second-hand clothing, conversion to new products, wiping and polishing cloths, landfill incineration for energy, and lastly diamonds. Typically within the pyramid model it is found that the volume of clothing items is inversely proportional to its monetary value, moreover meaning that despite diamonds making up the smallest sector (1-2%) of the sorting process they tend to be the most profitable.

Crude Sorting 
Within crude sorting, waste items are often manually separated into distinct categories whilst also removing bulkier items, such as coats and blankets. The categories of textile waste may be divided based upon elements such as material, condition, quality, or clothing item such as shirts. Employees with the most expertise perform the most detail-oriented distinctions such as being able to distinguish cashmere from wool by touch. Along the crude sorting process, recycled textiles are also assigned categoric grades representing their commercial value based upon various fiber characteristics such as length, color, and the homogeneity of its chemical composition.

Second Hand Clothing Exportation Markets 
The exportation of second-hand clothing is a growing global market; the trade market value doubled between the years 2007 and 2012 based upon declared reports alone. The exportation trend is most commonly from Western countries to developing countries or those experiencing disaster relief, with the United States of America being responsible for 45% of the total volume of Western exportation. In Africa specifically, Western clothing is a high commodity that imports $61.7 million of sales annually and in Sub-Saharan Africa these exports account for over a third of the total purchased garments.

Conversion of textile materials to New Products 
Clothing items that are not able to be resold may be converted into new products using their recycled fibers. Shoddy and mungo are the two main results of this process. Shoddy is one of the most historical examples of textile recycling and refers to creating yarn products from the old materials. Panipat in North India is one of the largest producers of shoddy yarn with over 300 mills, here the majority of shoddy is used to knit blankets. Mungo was invented after shoddy and refers to the process of using clippings of textiles when making wool, which is mostly exported to European countries due to the need for wool in the cooler temperatures and flammability regulations. Specific examples of products being produced using either shoddy or mungo include luxury blankets in Italy, fibers within US dollars, and the phenomena of sustainable fashion trends.

Wiping and Polishing Cloths 
Textiles that are deemed to be un-wearable during the sorting phase may be used to create wiping and polishing cloths that are called snakes, made from oleophilic and hydrophilic fibers. T-shirts are largely used when creating these cloths due to the naturally absorbent cotton fibers that have proven useful for cleaning up small oil spills within the oil industry.

Making and creating Energy from Landfill Incineration 
The textile materials that are not found to have a viable market in any of the above categories are either sent to the landfill or are incinerated to produce electrical energy. Though incinerating municipal solid waste (MSW) is not yet feasible in the United States, it has been prolific in countries such as Denmark, Japan, and Switzerland where over two thirds of MSW is incinerated. In terms of calories, the energy values of burning MSW have been comparable with oil but there are still obstacles with increasing incineration efficiency and reducing harmful byproducts of the incineration such as noxious gases and ash.

Advantages of recycling

Percentage usage of discarded textiles
70% of second hand materials, 8% of fibre reclaiming, 9% of stuffing, 7%recycled products, 6% of bags and zips.

Diamonds 
Diamonds make up the smallest sector of the sorting process, constituting the rare items of clothing that are considered collectibles and can be resold with a high profit margin. Diamonds are usually hunted and sold by small family businesses, the majority of these lie in Japan where consumers value Western brands such as Ralph Lauren, Levi's. and Harley Davidson. Whereas, the smaller diamond markets in America place a higher value and priority on items such as Italian leather and French Couture.

Methods of textile recycling

Mechanical 
Mechanical processing is the most commonly used technique to recycle textiles. Companies in the United States used about 7.6 million bales of cotton to manufacture textiles with each bale weighing 500 pounds. The cotton can be recycled through mechanical means after separating it from different materials. However, some plants can still process recycled material that is not purely made of cotton such as 98% cotton and 2% spandex. After an initial sorting, the raw material is further sorted by color to avoid re-dying and bleaching. Once done, the textile material is shredded and separated into fibers. The end product at this point is not usable yet and needs to be aligned before spinning. This process is known as carding. Now, the fibers are spun along with some virgin cotton fibers since recycled cotton fibers are shorter and lower in quality. Another commonly used material in mechanical processing is polyester. With this process, the recycled materials are not polyester textiles, but plastic bottles. Both are made of the same material known as polyethylene terephthalate (PET). Once the materials are sent to the facility, first they are sorted by color and type. Similar to cotton, the PET plastic is shredded into slices and washed to remove contaminants. The dried, shredded plastic is molded into PET pellets and undergoes extrusion to create new fibers.

Chemical 
Chemical processing is typically used on synthetic fibers such as Polyethylene terephthalate (PET) as these fibers can undergo a breaking down and recreation process. This process is not yet widely used, but there are companies that are researching and implementing chemical recycling. The major small scale production sites are from Eco Circle, Worn Again, Evrnu, and Ioncell. In the case of PET, the starting materials are first broken down to monomers. This is done by using chemicals that facilitate glycolysis, methanolysis, hydrolysis, and/or ammonolysis. This act of depolymerization also removes contaminants from the starting material such as dyes and unwanted fibers. From here, the material is polymerized to be used to produce textile products. Unlike the mechanical method of recycling, chemical recycling produces high-quality fibers similar to the virgin fiber used. Therefore, no new fibers are needed to support the product of the chemical process. Different chemicals and pathways are used for other materials such as nylon and cellulose-based fibers, but the overall structure of the process is the same.

Applications of recycled textiles 

Many clothing retailers across the world have implemented recycled textiles in their products. Companies like These retailers cater to environmentally conscious consumers by producing Sustainable Fashion.

Products made from recycled textile materials
Companies such as Patagonia, Everlane, Lindex, Pure Waste, and Heavy Eco sell sustainable clothes. These companies incorporate materials derived from textile post-consumer waste as well as recycled plastics into the clothes they sell.

Within Scandinavia specifically there are prolific applications of recycled textiles that have created mainstream market products. In Sweden, companies such as Lindex and H&M are including pre and post-consumer waste fibers within their new clothing lines. Similarly in Finland, Pure Waste is a clothing enterprise that creates t-shirts from recycled fibers in their 95% wind powered factories.

Aside from clothing, Egetæpper is a Danish carpet manufacturing company that makes their carpets using the fibers from recycled fishnets.

Glen Raven, Inc., a fabric manufacturer, engineered a program that collects unused pieces during production and recycles them into a new fabric. They also established a program for customers to recycle their old fabrics with the company.

See also 
Global trade of secondhand clothing
Sustainable fashion

References

Clothing and the environment
Recycling by product
Textiles
Water conservation