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ZDHC Updates Wastewater Treatment Technologies Guide

The Zero Discharge of Hazardous Chemicals (ZDHC) Foundation has updated its guidelines on how to improve the quality of wastewater discharge in the textiles, apparel and footwear sectors.  

The “ZDHC Wastewater Treatment Technologies” document, published Wednesday as part of the ZDHC Roadmap to Zero Programme, improves upon its 2016 predecessor by offering an “aligned set of parameters, limit values and test methods” that unifies expectations for brands and their suppliers across the globe, according to Frank Michel, executive director of ZDHC.

The organization is a collaboration among 24 signatory brands, 59 value-chain affiliates and 15 industry, NGO and government associates, including Adidas, Benetton Group, Burberry Group, C&A, Gap, H&M, Inditex (which operates Zara), Levi Strauss, Marks & Spencer, Nike, Puma and PVH Corp. It arose, in part, as a response to Greenpeace’s 2011 “Detox” campaign, which linked some of the world’s biggest brands with widespread water pollution in the developing world. 

The revelations weren’t wholly unexpected. Fashion is a filthy industry—literally. Creating shoes and clothing slurps up vast quantities of freshwater, which if left untreated and improperly discharged, can transform once-pristine waterways into highly toxic chemical cocktails.

Take, for instance, China, home to more than 50,000 textile mills and the target of Greenpeace’s original exposé. As much as 70 percent of its lakes, rivers and reservoirs are tainted by heavy metals, persistent organic pollutants and hormone-disrupting substances, according to the environmental nonprofit. As production has shifted to South and Southeast Asia, so has the issue of improper and imprudent discharge.

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One of the chief sources of pollution is effluent that contains synthetic dyes and other auxiliary chemicals, ZDHC noted in the document. More than 10,000 textile dyes are manufactured in excess of 700,00 tons per year. Because only 50 percent to 95 percent of the dyes used are fixated onto fabric, roughly 280,000 tons are released annually, “either to wastewater treatment plants or directly to the environment,” ZHDC said.

Although some dyes and auxiliary chemicals are biodegradable and “get absorbed into the biomass,” AZO dyes, which account for 70 percent by weight of all dyes used worldwide, do not, it added. 

Certainly the World Bank estimates that 17 percent to 20 percent of industrial water pollution comes from dyeing and finishing treatment given to fabrics.

ZDHC admits that wastewater treatment is a “complex process” for the textiles, apparel and footwear sectors, but it says it hopes that its technical overview, together with regional training programs, will help “close the knowledge gap” on available technologies that can help fabric mills and other relevant facilities meet the organization’s goal of discharging zero hazardous chemicals by 2020.

“Given the complexity of textile effluent, a proper understanding of textile effluent and its treatment is necessary to make the industry sustainable and pollution free,” it said.