Here is an interesting article from Apparel showing how ozone is helping to reduce the environmental impact of the production of denim jeans.

“Ozone Finishing for Denim Reduces Environmental Impact, Processing Costs and Processing Time
08/01/2014
Global demand for jeans has been projected to reach $56.2 billion this year. Trend forecasts continue to showcase denim as a wardrobe staple. While dark washes are reappearing, consumers worldwide still love bleached, stonewashed jeans, jeans jackets, vests and skirts. Manufacturers achieve these finishes with water, chemicals, enzymes and pumice stones. According to Levi Strauss & Co., the average pair of jeans uses 42 liters of water in the finishing process. A recent survey I did in 10 factories overseas supports that figure; factories I visited reported using 20 liters to 60 liters of water to finish each pair. Meanwhile, 900 million people lack access to clean water. A 2012 United Nations report says growing demand for water matched against static or shrinking supplies … point(s) unerringly in the direction of greater conflict over water. Responsible water use is of health and safety importance.
Forward-thinking brands and manufacturers are seeking alternatives to water, chemicals and stones for achieving the faded look consumers crave. Leading brands are sensitizing consumers to reduced water and chemical use; while conducting market research in Europe and the Middle East last summer, I found brands advertising low water, low chemical and no chemical finishes directly to the consumer.
Two water-saving, bleaching technologies are commercially viable today: laser and ozone.
Low water, low chemical, no chemical hangtags
Laser. Computer-driven laser technology can replicate localized wear, whiskers, and intricate lacelike patterns without water, chemicals or stones. Laser offers precise, repeatable bleaching. However, equipment is costly, each garment must be individually positioned for treatment, and only one side can be treated at a time. Excellent for localized effects, laser is less beneficial for overall bleaching.
Ozone. Ozone technology harnesses the natural bleaching capabilities of ozone gas to give a range of overall and specialty bleach effects with substantially reduced environmental impact. Ozone can be used to clean pocket backstaining from normal washing processes, or to bleach denim to a lighter shade.5 The photograph on the following page shows the range of bleachdown achievable by varying ozone concentration and exposure time. Individual brands are also creating unique specialty looks with the power of ozone.
Ozone does not eliminate water use in jeans finishing. However, it substantially reduces consumption of water as well as energy, chemicals, enzymes and stones. Ozone offers important advantages over traditional wet finishing.
Oxygen (O2) is converted to ozone gas (O3), jeans are dampened, exposed to the ozone, and rinsed; the ozone is reconverted to ordinary oxygen before release into the environment. While chemical bleaching or stonewashing uses six to seven washes and rinses, ozone finishing requires two to three. A production manager I spoke with reported more than 50 percent reductions in water, chemicals and pumice stone consumption when using ozone finishing in sequence with reduced traditional wet finishing methods.
Ozone finishing reduces energy consumption by reducing the amount of water that must be heated for wet finishing, and the temperature required. Furthermore, replacing some traditional finishing with ozone reduces effluent, including the sludge pumice stones create.
Ozone bleaches more quickly than chemicals and stonewashing. Ozone can clean back stains in three seconds. At optimum concentrations, it bleaches denim in 15 minutes to levels commonly desired by fashion today, versus 30 to 45 minutes with traditional methods. Ozone increases production per shift.
Ozone technology reduces environmental impact, processing costs and processing times while achieving desirable fashion looks.
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Ozone technology doesn’t fully replace chemical bleaching, stonewashing and enzymes for jeanswear, but used alone or in sequence with traditional processing, it reduces environmental impact, operating costs and processing times. The caveat? When best-of-class equipment is used, ozone technology can be used safely and with consistent, repeatable finishing results.
Margaret Bishop is a global consultant to the textile and apparel industry, and an Adjunct Instructor in the Departments of Textile Development and Marketing, and International Trade and Marketing at the Fashion Institute of Technology in New York. She may be reached at M.L.Bishop.2011@gmail.com.”
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For the full article, click the link provided above.