Pulp production is pretty straightforward and a dirty process. I will talk about water and energy usage in other sections. I want to focus this section on the bleaching process.
It all starts with elemental chlorine (Cl2). Simple put, elemental chlorine produces carcinogenic compounds and is hazardous to the environment. While it has declined over the years, it still persists in the industry and it might hold anywhere from 5-20% of the global market share. This amazes/frustrates me, as it should be zero!
On the other side of the debate we have ECF (Elemental Chlorine Free) and TCF (Totally Chlorine Free). While the name might be confusing, ECF does contain low doses of chlorine dioxide but is completely free of elemental chlorine. TCF is 100% chlorine free and uses an oxygen based process to bleach the pulp. While some environmentalist tend to side on the chlorine free method (including myself), some research identifies the environmental impact of both ECF and TCF as similar.
In studies done by the European Union, they concluded that, “it is now possible to demonstrate that the discharges to watercourses, from both ECF and TCF, are of no environmental concern”. The ECF process might even use less energy. The study did acknowledge that adsorbable organic halides (AOX), which are bad, were still present in the ECF process even after effluent treatment. However, they noted that the amount of AOX was insignificant. I did not see an examination or discussion of the problems at scale. Toxicity levels were present in both methods but at low levels. My point being, since ECF holds a market share of possibly 94%, compared to TCF which holds roughly a 5% market share, shouldn’t we think about diversifying our bleaching processes (ECF and TCF). This would minimize the effects of AOX exposure to the environment and provide more data. Oh, and we should just ban elemental chlorine outright!
Lastly, Lenzing only uses TCF bleaching in its internal processes. For all sourced imported pulop, ECF bleaching is used. Also, all by-products from Lenzing's internal pulp production process which include acetic acid, furfural, xylitol, magnesium lignosulfonate, soda (sodium carbonate), magnesium lignosulfonate, soda (sodium carbonate) are used in their biorefinery to produce energy for their plants in Czech Republic and Austria.