1. Department of Mathematical Modelling, Statistics and Bio-informatics, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
2. DC Water and Sewer Authority, 20032 Washington, DC, USA
3. ARAconsult, Unterbergerstr.1, A-6020 Innsbruck, Austria
4. Department of Earth and Environmental Engineering, Columbia University, New York, NY, USA
5. Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Ghent, Belgium
6. Civil and Environment Engineering Department, Old Dominion University, Norfolk, VA 23529, USA
7. Hampton Roads Sanitation District, Virginia Beach, VA 23455, USA