Tanning leather doesn’t have a reputation for being very “clean.”
The process for turning rawhides into durable leathers uses heavy-duty dyes and tanning solutions that contain toxic compounds that can create problems in waste water and in the atmosphere. And the water and energy demands are immense.
But with 56 percent of the footwear sold last year in the U.S. made of leather (that’s 1.1 billion pairs), reducing the environmental impact of the process would be a major step in reducing the impact of footwear manufacturing. Innovative new methods to cut energy use, recycle water and reduce the carbon impact of tanning are being enacted every day.
Here, Footwear News went to some of the industry’s leading tanneries to find out what they’re doing to go green now and later on down the road.
Location: Huizhou City, China
Capacity: 4 million sq. ft./month
Clients: Adidas, Ariat, Camper, Clarks, Columbia, Keen, Lacoste, MBT, Merrell, Nike, Sperry Top-Sider and Timberland
Now: When Simona Tanning opened in 2006, a top goal was to create a lower-impact facility. “If we were going to enter this business, we wanted to be in it on a world-class level,” said Keith Hill, president and COO. Simona was the first tannery in China to receive the Leather Working Group’s gold status, in part for its focus on efficient treating and reusing of water — a major concern because an average tannery can use as much as 44,200 cubic meters per month. Simona created a comprehensive system to salvage as much water as possible during the tanning process. A membrane bio reactor system was put in place in June 2008 to reduce suspended solids and organic pollutants in water used to re-tan the hides, and a reverse osmosis system installed later that year filters the treated water so it can be reused in the tanning process. The system, which Hill estimated cost 30 percent to 35 percent more than a standard effluent treatment system, has reduced both Simona’s fresh water use and its water discharge by 40 percent.
Future: Even though continued water reduction and reuse isn’t a major cost saver for the tannery, it’s a big focus going forward. A pilot program to use reed beds to further filter water (reducing chemical use by 20 percent and energy costs by 30 percent) began last summer, and Hill expects to have a permanent installation the size of three football fields operational by March 2011. And a program to collect the rainwater that is abundant in Huizhou City could net the tannery as much as 20 percent of its water needs when it’s finished. Looking even further forward, new technologies, such as infrared dryers, will be the key to cutting back on energy, water and waste, Hill added. “We’ll continue to invest in technologies that will get us there,” he said. “We need to do everything we can to reduce the carbon footprint.”