**2. An overview of the global denim market**

Denim is a type of sturdy cotton twill woven fabric with a characteristically diagonal ribbing known for its use in the form of jeans and other clothing all across the world. Originally used for workers' clothes, denim has entered the world of high fashion for a long time, and this has urged the industry to produce innovative denim with different fibers including lyocell, bamboo, viscose, rayon, polyethylene terephthalate, and elastane. Also, several types of washes have been introduced, such as stonewash and stoneless wash, acid wash, moon wash, monkey wash, and enzymes which have been used because of their environmental-friendly nature in comparison with hypochlorite and pumice stones [2].

Rising casualization of clothing all over the world, together with the availability of high-quality, cost-effective denim products, has contributed to the growth of the market over the years. E-commerce is the other factor which has a positive influence on the denim market's growth. In addition, brands have started to reinforce their commitments to responsible production efforts and launched more sustainable collections to the market, which has dramatically increased new retail products described as "sustainable" since 2017. Orta Anadolu, for example, introduced its organic cotton production of denim fabrics in 2006 and a capsule collection without virgin cotton in 2018. Similarly, Diesel launched a sustainable capsule collection with Coca-Cola [3].

The global denim market is segmented into North America (NA), Europe (EU), Asia-Pacific (APAC), the Middle East and Africa (MEA), and South America (SA). The major companies operating in the global denim market are Levi Strauss & Co., VF Corporation (with renowned brand names of Lee and Wrangler), Diesel SpA, Gap Inc., Hennes & Mauritz AB, Inditex, and PVH Corp., and Tommy Hilfiger Licensing LLC. The jean market is a highly fragmented market, with a strong presence of local and global players operating all over the world. Thus, to sustain their positions in the market, the active players are bringing innovation in their product offering, in order to cater to changing consumers' fashion lifestyle [4].

Also, they have been focusing on social media platforms as well as online distribution channels for their marketing and branding activities so as to attract more customers. Denim manufacturers, however, appear to focus on acquisitions, expansions, and collaborations with mostly startup companies to gain a significant market share [2–3].

## *Understanding Denim Recycling: A Quantitative Study with Lifecycle Assessment Methodology DOI: http://dx.doi.org/10.5772/intechopen.92793*

In 2019, the global denim market was valued at approximately 90 billion US dollars and is expected to reach a value of around 107 billion US dollars by 2023 [5]. The global denim jean market size, on the other hand, was valued at USD 64.62 billion in 2018, and it is estimated to expand further at a compound annual growth rate (CAGR) of 6.81% from 2019 to 2025 [6]. The Asia-Pacific region led the market in 2019, which was followed by North America, Europe, South America, and the Middle East as a response to the introduction of global brands and an emphasis on premium denim. Japan, China and India are expected to lead the region through 2024 as a result of the countries' rise in promotional activities within the denim market [2, 4].

According to the World Denim Fabric Foreign Trade Report published by the Istanbul Textile and Raw Materials Exporters Association (ITHIB), global denim fabric exports increased by 5.1% in 2018 and reached approximately 5 billion US dollars. The top five countries performing most denim exports are China (42% share of total exports), Pakistan (11.7% share of total exports), India (8.2% share of total exports), Hong Kong (7.4% share of total exports), and Turkey (6.8% share of total exports). It is stated that there is a strong growth in the denim production in Bangladesh and Vietnam, although these countries are mostly importing denim fabric [7].

Europe, the United States, and Japan are the biggest consumers of denim, whereas China and India, being relatively younger economies, are witnessing a steady rise in demand for denim. In 2018, men's wear segment accounted for the largest market share of more than 55%. It is forecasted that the segment will retain its leading position over the upcoming years mainly because of the improved standards of living and demand for trendy fashion apparels. Women's wear segment is, on the other hand, expected to register the fastest compound annual growth rate (CAGR) of 7.25% from 2019 to 2025. This growth is attributed to the high product demand, especially in emerging countries. In addition to that, constant product innovation in this segment is also expected to drive the growth further [2, 6].

#### **2.1 Environmental impacts of denim processing**

It is estimated that producing a pair of jeans consumes around 2900 liters of water and large amounts of chemicals and energy. If this is multiplied by the number of jeans produced globally, one can get an idea of the enormous contribution of wastewater and harmful gases by denim industry to the environment [8, 9].

Indigo dye is one of the organic colorants used to color textiles, paper, leather, and plastic and for many applications such as cosmetic and photochemical production. Unfortunately, textile effluents containing indigo dye and other dye types make water toxic and harmful for human and animal consumption, which causes an imbalance in different aquatic ecosystem food chains [10]. The use of synthetic indigo and sulfur dyes also presents serious effluent problem. Bearing in mind that majority of warp dyeing for denim uses indigo and sulfur dyes, the environmental impacts of denim processing can be classified into three main categories:


As is well-known, denim washing is imparted to fabric to improve the softness, comfort, and most importantly achieving a variety of looks such as a faded or

designs are monomaterials, elimination of toxic substances, modular manufacturing for ease of removal or exchange, easily compatible materials, and labels or codes

The environmental impact of denim products, during manufacture, use, or disposal, can be evaluated by looking at the different phases of the product's life cycle and taking action at the phases where it will be most effective to reduce the impact. However, the lifecycle of a product is long and complicated, covering many areas with many people involved in each phase [1]. There is a variety of voluntary and mandatory tools which help achieve this objective. These include economic instruments, bans on certain substances, environmental labeling, voluntary agreements, product design guidelines, etc. Life cycle assessment (LCA) methodology is one of the aforementioned tools, and within the frame of this chapter, it is adopted to quantify and compare the environmental impact of recycled denim fabrics. But

before that, the global denim market, environmental impacts of denim

textiles and apparel today are also discussed in this chapter.

**2. An overview of the global denim market**

son with hypochlorite and pumice stones [2].

with Coca-Cola [3].

market share [2–3].

**60**

manufacturing, sources of denim waste, and recycling processes currently used in

Denim is a type of sturdy cotton twill woven fabric with a characteristically diagonal ribbing known for its use in the form of jeans and other clothing all across the world. Originally used for workers' clothes, denim has entered the world of high fashion for a long time, and this has urged the industry to produce innovative denim with different fibers including lyocell, bamboo, viscose, rayon, polyethylene terephthalate, and elastane. Also, several types of washes have been introduced, such as stonewash and stoneless wash, acid wash, moon wash, monkey wash, and enzymes which have been used because of their environmental-friendly nature in compari-

Rising casualization of clothing all over the world, together with the availability of high-quality, cost-effective denim products, has contributed to the growth of the market over the years. E-commerce is the other factor which has a positive influence on the denim market's growth. In addition, brands have started to reinforce their commitments to responsible production efforts and launched more sustainable collections to the market, which has dramatically increased new retail products described as "sustainable" since 2017. Orta Anadolu, for example, introduced its organic cotton production of denim fabrics in 2006 and a capsule collection without virgin cotton in 2018. Similarly, Diesel launched a sustainable capsule collection

The global denim market is segmented into North America (NA), Europe (EU), Asia-Pacific (APAC), the Middle East and Africa (MEA), and South America (SA). The major companies operating in the global denim market are Levi Strauss & Co., VF Corporation (with renowned brand names of Lee and Wrangler), Diesel SpA, Gap Inc., Hennes & Mauritz AB, Inditex, and PVH Corp., and Tommy Hilfiger Licensing LLC. The jean market is a highly fragmented market, with a strong presence of local and global players operating all over the world. Thus, to sustain their positions in the market, the active players are bringing innovation in their product offering, in order to cater to changing consumers' fashion lifestyle [4]. Also, they have been focusing on social media platforms as well as online distribution channels for their marketing and branding activities so as to attract more customers. Denim manufacturers, however, appear to focus on acquisitions, expansions, and collaborations with mostly startup companies to gain a significant

that can be recycled.

*Waste in Textile and Leather Sectors*

worn-out appearance. Pumice stone is used to stonewash denim garments. The stone gets abraded during the process and becomes powdered; part of it remains in the liquor, and part of it sticks to the garment. A sizeable amount of water is required for repeated washing cycles to remove the deposited pumice from the denim. The effluent and pumice dust lead to environmental pollution. Sandblasting is a mechanical finish which uses sand containing silica. The minute silica dust spreads in air, it poses serious respiratory disease such as silicosis [10].

material. The remaining 20% of the clothes are either sold on the second-hand

*Understanding Denim Recycling: A Quantitative Study with Lifecycle Assessment Methodology*

As one of the sources of solid waste, the cutting waste during denim jean production—which has relatively a homogeneous nature—is between 10% and 15%, and most of the waste is recycled by unraveling and reusing the fibers in the production of insert yarns (weft direction), which is a good example of "recycling

Another source of denim waste is the post-consumer denim jeans. Color, quality of fabric, and garment accessories like rivets, buttons, zippers, and labels are the main components of the heterogeneous nature of this very denim waste. The main problem is the collection of post-consumer jeans. Although in many countries collection systems are in place, many consumers discard their jeans as solid municipal waste. Jeans that are collected are mostly sold to textile sorting companies which manually/automatically sort the rewearable jeans for sale to second-hand shops and in Third World countries. Nonwearable jeans are, however, shredded and used for the development of various types of products such as thermal and acoustic insulators and/or textile-based composites for certain structural and other special-

Finally, as a different approach to decreasing the denim waste regarding postconsumer denim jeans, the leasing of jeans was introduced several years ago by MUD Jeans. In this concept, the producer or distributor of the jeans stays the owner. The user of the jeans only "buys" the right to the use the jeans for a period of 1 year. If the jeans need to be repaired, it is at the cost of the lease company [22]. The same company, together with several of others, has also focused on "design for recycling (D4R)" for facilitating the recycling of denim jeans, such that they do not use leather labels but printed ones at the waistband, employ rivets and buttons that are made from 100% stainless steel and no finishing (electroplating), and have utilized buttons made out of recycled jeans on their denim shirts and sweaters, etc.

An average person buys 60% more clothing items every year and keeps them for

half as long as they used to keep about 15 years ago. It is assumed that overall consumption of textiles will have reached to 102 million tons by 2030 and that the textile industry's waste will have increased by about 60% between 2015 and 2030. That means the total level of fashion waste will reach to 148 million tons in 2030. As is known, the majority of clothing waste ends up in landfills or is incinerated, and once in landfills, it takes hundreds of years for natural fibers to decompose and may release methane and CO2 into the atmosphere. Synthetic materials, on the other

**3. An overview of recycling in textiles and apparel**

in design (RiD)." Most jeans' producers recycle denim waste in their own manufacturing plants or have contracts with textile waste recyclers to reuse the waste material in the spinning of new yarns. There is also substantial trade of denim

Being the largest fraction of apparel, waste jeans (or waste denim fabric from tailoring operations) are composed mainly of "cotton" and "cotton/polyester" fabric with different weight ratios [19]. Although this may lead to the understanding that denim made with 100% cotton, in particular, will readily deteriorate in the environment, in practice a pair of such jeans can stay alive in the environment for a very long time, and therefore the negative environmental impact is very high. The literature reveals that the amount of waste jeans generated annually is estimated as 2.16 million tons and only 35–50% of this amount is collected in Western Europe in

market within the EU or is sent to landfill or incineration [18].

order to reuse or recycle it after sorting [13, 20–21].

*DOI: http://dx.doi.org/10.5772/intechopen.92793*

waste all over the world [13, 21–22].

ized applications [13, 21, 23–28].

[13, 29–30].

**63**

Micro sanding is another finish which pollutes the environment. In the case of chemical washing involving the use of sodium hypochlorite or potassium permanganate, the effluent contains chlorinated organic substances which cause severe impacts to the environment, and the bleaching chemicals are harmful to human health. Acid wash uses both pumice stone and chemicals, namely, sodium hypochlorite or potassium permanganate, and it does not require water but leads to pollution through the effluent having pumice dust and residual manganese which are hazardous [11–12].

Despite all these setbacks of the denim processes summarized above, various suitable treatment processes have been developed and employed for the dyeing effluent on the basis of the nature and complexity of the dyes and chemicals present in denim. Fortunately, many denim companies and their suppliers have been striving hard to embrace greener methods such as laser processing and nano bubble ozone washing machines and are also making effort to develop new techniques of producing jeans, as a part of their business strategies to preserve the environment. They have also understood the importance and the need to build a sustainable business [12–14].

#### **2.2 Sources of denim waste**

It is considered that sustainable material management is a precursor of circular economy, which promotes recycling, reuse, and remanufacturing. It was estimated that around 65 billion tons of raw materials were processed by the industrial system at the end of the first decade of the twenty-first century, and this quantity is expected to reach about 82 billion tons by the end of 2020. Therefore, in the last two decades, circular economy (CE) is gaining growing global consideration as the new development model which is capable of influencing the existing production and consumption model [15]. Within that concept, waste is classified on the basis of generation as pre-consumer textile waste, post-consumer textile waste, and industrial textile waste. Pre-consumer waste is the remaining production processes in the industry which includes raw material to finished products ready for market. This may include offcuts, shearing, selvedges, b-grade garments, export surplus, etc. which are homogenous and clean in nature to be used for other purposes. The waste under this class has great potential for reuse and recycling. The post-consumer textile waste can include any product that has completed its life cycle and is no longer useful to the consumer in both function and esthetics. Industrial textile waste is, however, the result of the manufacturing processes and is termed as dirty waste [13, 16].

The textile and apparel industry, which generates a substantial environmental footprint from cultivation, fabric and garment manufacturing, to the landfill disposal of post-consumer items, faces tremendous environmental and resource challenges [17]. In order to tackle such challenges to some extent, several fashion companies offer their customers to take care of their worn-out clothes including denim jeans. However, studies have concluded that less than 1% of these collected clothes are being recycled while nearly 80% of them are mainly sold on the secondhand market in poor countries around the world or used as blankets or isolation

### *Understanding Denim Recycling: A Quantitative Study with Lifecycle Assessment Methodology DOI: http://dx.doi.org/10.5772/intechopen.92793*

material. The remaining 20% of the clothes are either sold on the second-hand market within the EU or is sent to landfill or incineration [18].

Being the largest fraction of apparel, waste jeans (or waste denim fabric from tailoring operations) are composed mainly of "cotton" and "cotton/polyester" fabric with different weight ratios [19]. Although this may lead to the understanding that denim made with 100% cotton, in particular, will readily deteriorate in the environment, in practice a pair of such jeans can stay alive in the environment for a very long time, and therefore the negative environmental impact is very high. The literature reveals that the amount of waste jeans generated annually is estimated as 2.16 million tons and only 35–50% of this amount is collected in Western Europe in order to reuse or recycle it after sorting [13, 20–21].

As one of the sources of solid waste, the cutting waste during denim jean production—which has relatively a homogeneous nature—is between 10% and 15%, and most of the waste is recycled by unraveling and reusing the fibers in the production of insert yarns (weft direction), which is a good example of "recycling in design (RiD)." Most jeans' producers recycle denim waste in their own manufacturing plants or have contracts with textile waste recyclers to reuse the waste material in the spinning of new yarns. There is also substantial trade of denim waste all over the world [13, 21–22].

Another source of denim waste is the post-consumer denim jeans. Color, quality of fabric, and garment accessories like rivets, buttons, zippers, and labels are the main components of the heterogeneous nature of this very denim waste. The main problem is the collection of post-consumer jeans. Although in many countries collection systems are in place, many consumers discard their jeans as solid municipal waste. Jeans that are collected are mostly sold to textile sorting companies which manually/automatically sort the rewearable jeans for sale to second-hand shops and in Third World countries. Nonwearable jeans are, however, shredded and used for the development of various types of products such as thermal and acoustic insulators and/or textile-based composites for certain structural and other specialized applications [13, 21, 23–28].

Finally, as a different approach to decreasing the denim waste regarding postconsumer denim jeans, the leasing of jeans was introduced several years ago by MUD Jeans. In this concept, the producer or distributor of the jeans stays the owner. The user of the jeans only "buys" the right to the use the jeans for a period of 1 year. If the jeans need to be repaired, it is at the cost of the lease company [22]. The same company, together with several of others, has also focused on "design for recycling (D4R)" for facilitating the recycling of denim jeans, such that they do not use leather labels but printed ones at the waistband, employ rivets and buttons that are made from 100% stainless steel and no finishing (electroplating), and have utilized buttons made out of recycled jeans on their denim shirts and sweaters, etc. [13, 29–30].
