1. Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B-9000 Ghent, Belgium, Advanced Wastewater Management Centre, University of Queensland, Brisbane, QLD 4072, Australia, and Laboratory of Applied Physical Chemistry (ISOFYS), Ghent University, Coupure Links 653, B-9000 Ghent, Belgium