1. Assistant Professor, Faculty of Civil Engineering, Dept. of Environmental Engineering, Istanbul Technical Univ., 80626 Maslak, Istanbul, Turkey (corresponding author).
2. Dr., Institute of Environmental Engineering, Dept. of Water Quality Control, Technical Univ. Berlin, Secr. KF 4, Strasse des 17. Juni 135, 10623 Berlin, Germany.
3. Full Professor and Head, Institute of Environmental Engineering, Dept. of Water Quality Control, Technical Univ. Berlin, Secr. KF 4, Strasse des 17. Juni 135, 10623 Berlin, Germany.