Covestro (Leverkusen / Germany: www.covestro.com) has inaugurated a new pilot plant at Krefeld-Uerdingen / Germany for recycling of saline process water from polycarbonate production. The EUR 3.7m facility, for which Germany’s federal environment ministry, Bundesumweltministerium (BMU, www.bmu.de), provided funding of EUR 740,000, was dedicated on 29 January in the presence of environment minister Barbara Hendricks.

The former Bayer MaterialScience said the new technology will ease the wastewater burden on the Rhine river by reducing salt levels and conserving potable water resources. Klaus Jaeger, site manager for Covestro plants in the state of North Rhine-Westphalia, said the PC recycling project marks the first time that saline industrial wastewater has been recycled at an industrial pilot plant. In the state, pre-treated process water is usually released into waterways, in particular the Rhine, on which the Krefeld site borders.

Along with relieving the burden on waterways, Covestro said some of the wastewater can be reused in an electrolysis process to make chlorine, a key raw material for polycarbonate. The company claims the new process will help save 30,000 t/y of salt and 400,000 t/y of desalinated water in chlor-alkali electrolysis per year, thus also avoiding the emission of 6,200 t/y of CO₂ annually. Hourly, the process is said to prevent the release of 70 m³ of saline wastewater. The engineering plastics firm spun off from Bayer and listed on the Frankfurt stock exchange last year – see Plasteurope.com of 23.09.2015 – also touted its existing oxygen depolarised cathode technology for the chlor-alkali electrolysis process, which it said consumes 30% less energy than the standard process.

Plasteurope.com’s Polyglobe capacity database (www.polyglobe.net) shows that Covestro has capacity to produce 400,000 t/y of polycarbonate at Krefeld.