1. Vito, Environmental Technology, Boeretang 200, B-2400 Mol, Belgium (E-mail: heleen.dewever@vito.be; sandra.vanroy@vito.be; chris.dotremont@vito.be)
2. ESWE-Institute for Water Research and Water Technology, Kurfürstenstraße 6, D-65203 Wiesbaden, Germany (E-mail: thomas.knepper@eswe.com; jutta.mueller@eswe.com)