Swiss chemical process makes eco-friendly jeans

It takes lots of water and chemicals to make a pair of jeans, and environmentally conscious clothing makers caught on years ago to the need to make more sustainable versions these popular pants.

But a Swiss chemical company said Tuesday its process for making eco-friendly jeans could streamline those efforts, saving enough water to cover the needs of 1.7 million people per year if one quarter of the world's jean-makers started using it.

The dying technology, known as Advanced Denim, was described at the 16th annual Green Chemistry & Engineering Conference, sponsored by the American Chemical Society's Green Chemistry Institute.

Miguel Sanchez, a textile engineer at Clariant, said the technique can produce a pair of jeans using up to 92 percent less water and up to 30 percent less energy than conventional denim manufacturing methods.

Traditional techniques may require as many as 15 dyeing vats and a host of chemicals, while Advanced Denim uses one vat and a new kind of liquid sulfur dye that requires just one sugar-based reducing agent, he said.

The process, if used on a wide scale, could save 2.5 billion gallons of water per year, prevent the release of 8.3 million cubic meters of wastewater and save up to 220 million kilowatt hours of electricity, he added.

"Advanced Denim wants to go beyond the technologies that are today considered standard for obtaining denim material," Sanchez said.

Many other companies, including denim-giant Levi-Strauss, already make their own versions of eco-friendly jeans that use less water, are made with organic cotton, or use natural dyes. These products remain a niche market, however.

Jeans, particularly those that are distressed to appear as if they have been worn, have come under fire in recent years for wasting water, overusing harmful chemicals and using sandblasting that can endanger workers' health.