Lenzing AG - Case Study
Viscose fibre producer solves three problems with one solution
Lenzing A.G. from Austria is a world leader in viscose fibre production from wood. In 2009 they produced 568,600 tonnes. Their main site is in Lenzing, Austria.
The manufacture of viscose fibres from wood produces a range of secondary compounds. Some streams, such as polluted sodium sulphate, cannot be reused and need to be discharged. Waste organic pollutants are degraded in a large aerobic wastewater treatment plant. In 2001, the maximum allowable sulphate discharge was reached which hindered further expansion of the production site.
A SULFATEQ™ system was installed in 2002 to treat three different streams, both acidic and alkaline. This installation converts three types of dissolved compounds: organic material (COD), sulphate and zinc. The plant produces sulphur and zinc sulphide. Here is a simplified representation of the flow scheme: