1. Institute of Hydrology and Water Management, Department of Water, Atmosphere and Environment, University of Natural Resources and Life Sciences, Vienna (BOKU) Muthgasse 18, 1190 Vienna, Austria
2. Department of Biological Sciences, Egerton University, Egerton P.O. Box 536-20115, Kenya
3. Department of Biosystems and Environmental Engineering, Technical University of Kenya, Nairobi P.O. Box 52428-00200, Kenya
4. Institute of Chemical, Environmental and Bioscience Engineering, Vienna University of Technology (TU Wien), Getreidemarkt 9/166, 1060 Vienna, Austria