Sustainable Washing in Denim Industry

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Srabani Mallick

Is there sustainable denim? Will denim ever be sustainable? These are the questions we have heard time and time. Centuries ago, denim was used in a limited range, but with its versatility, the demand for denim has now increased in the world market. Denim is essential apparel item in our everyday wear and current fashion especially jeans but it has a negative impact on the environment. Denim washing is considered to have a direct effect on the environment because of its chemical discharge and many other pollutants emitted during the process that affects the water supply. However, this article tries to describe how sustainability can be achieved through the most recent washing techniques that benefit the producer, the consumer and the planet.

Why should we focus on sustainable denim?  

Denim is always popular in fashion. Denim is a type of fabric that is used to make garments like jackets, shirts and jeans made from 100% cotton twill or stretch twill where cotton is a water- intensive crop. It costs at least 1800 gallons of water to make one pair of blue jeans and the chemical dyes most commonly used indigo dye are very toxic and expensive. Where denim is produced especially washed the fertility of the surrounding land decreases. Besides, its liquid waste also contaminates rivers and other sources of water. Not only that denim factory workers themselves often get very little protection from chemical residues, heavy metals, strong bleach, oxidizing agents as well as blue pigment dust. As a result, they often suffer from a significant health problem. Currently various international brands like Levi’s, Tommy Hilfiger, Uniqlo have developed sustainable denim to prevent such problems.

The main vision of sustainable denim wash:

Sustainable denim washing is a modern trend of washing that enhances the softness and comfort of the fabric. This type of wash is environmentally friendly which saves time, water, energy and chemicals. In modern times these are very important for the textile industry. Some sustainable issues in the denim industry can be categorized as follows:

  • Less water consumption for the blue planet.
  • Elimination of wastewater and reuse of water.
  • Use of environmentally free chemicals and eco-friendly dyes.
  • Less energy for efficient manufacturing.
  • Increase productivity.

Sustainable denim washing process

For stone effect: In the traditional method, pumice stone is used to wash the stone for giving a faded and well-worn look to the fabric. Pumice stones were washed with denim garments in large machines which involved high labor costs as well as residual and dust had to be removed manually. Instead of this, a solution based on an abrasive stainless steel drum has been developed by Tonello in collaboration with Levi Strauss and Co. The No stone Solution reduces water consumption, production costs, emission, waste, manual labor. Also, stone wash has some alternative methods like perlite stone wash, Bio-stoning; Rinse (water) washes etc.

For bleach effect: Traditional method of bleaching involved the use of heavy chemicals that are used to decolorize indigo. The continuous exposure of these chemicals causes corrosion to machines, weakens the fabric and can be harmful to workers. Instead of this, Ozone fading Technology is used where ozone is use as a powerful bleaching agent. It can be used to wash pocket back staining and bleach fabric to a lighter shade. Ozone technology utilizes the natural bleaching power of ozone gas to greatly reduce the environmental impact. Ozone is transformed ordinary oxygen before being released into the atmosphere.  Thus the environmental impact is reduced and production is increased through this technology.

For whisker effect: In the traditional method, potassium permanganate (pp spray) is used on jeans to fade color and lighten a specific area. Sometimes pp spray is mixed with acetic acid/phosphoric acid to enhance its intensity. Factory workers come into contact with the spray when working with the chemical; it irritates the skin and eyes which leads to short and long- term health problems. Instead of this, Laser technology is used for creating vintage effects, whiskers, patterns, patches and even intentional holes and tears in a garment. Using this technology, takes less water, chemicals and energy to create different denim looks. Also, laser boosters can be used to the fabric to intensify the laser effect.

For sanding effect: In the traditional method, manual sanding and sandblasting are used. Manual sanding can be applied to create rips, faded areas by physically scrapping and other worn effects in localized areas. Sandblasting uses compressed air to spray on the selected portions of apparel at high pressure. But this is extremely hazardous to workers. Instead of this, Laser technology can also be used to mimic hand sanding and sandblasting. This process is very quick and gives a distressed or vintage look to the denim.

Is enzyme wash sustainable?

Enzyme washing technology relies on biotechnology where cellulose enzymes are applied to denim. In this process, celluloses act on exposed cellulose on the cotton fibers which releases indigo dye from the fabric. Enzyme washing is considered more sustainable than acid or stone washing for the reason that it is more water- efficient and the substrate-specificity of enzymes also makes the technique more refined than other methods of processing denim.

Software for measuring sustainability in washing

1) Environmental impact measuring (EIM) software: Environmental impact measuring (EIM) software is the initial software that provides the laundries and garment finishers with a tool that helps them to build a more sustainable process. It is used to assess the environmental impact of finishing such as water use, energy consumption, use of chemical products, the health of workers etc.

2) Environmental Score (eScore) software: VAV Technology developed the eScore software especially for the denim manufacturing companies that measure the water, electricity and chemical quantities consumed by the machines based on the prescriptions and compare it with the reference values.

Conclusion

Denim is an important item of clothing for many decades. The traditional methods associated with denim washing cause serious damage to the environment and health. So we need to use new technologies like ozone, laser technology so as not to create adverse effects on the environment and focus on sustainable denim washing to enhance the development and sustainability in the denim industry.

References

1) https://www.cottonworks.com/en/topics/sourcing-manufacturing/denim/sustainable-denim-finishing/

2) https://advancetextile86.blogspot.com/2020/05/sustainable-denim-washing-process.html?m=1

3) Sustainable Solutions for Denim Processing | Abiteks

4)https://www.researchgate.net/publication/349920963_Sustainability_Issues_of_Various_Denim_Washing_Methods

5) Enzyme washing – Wikipedia

6) Ozone Finishing for Denim Reduces Environmental Impact, Processing Costs and Processing Time | News | Apparel Magazine(AM) (risnews.com)

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