1. Kiwa N.V., Water Research, P.O. Box 1072, 3430 BB Nieuwegein, The Netherlands (E-mail: gilbert.galjaard@kiwa.nl)
2. NV PWN Water Supply Company North Holland, P.O. Box 2113, 1990 AC Velserbroek, The Netherlands (E-mail: joop.kruithof@pwn.nl)
3. International Institute for Infrastructure, Hydraulics and Environmental Engineering, IHE Delft, P.O. Box 3015, 2601DA Delft, The Netherlands