1. Associate Professor, Dept. of Civil Engineering, Aalborg Univ., Sohngaardsholmsvej 57, 9000 Aalborg, Denmark (corresponding author).
2. Professor Emeritus, Dept. of Biotechnology, Chemistry and Environmental Engineering, Aalborg Univ., Sohngaardsholmsvej 57, 9000 Aalborg, Denmark.
3. Lecturer, Dept. of Chemical and Biological Engineering, Univ. of Sheffield, Mappin St., S1 3JD Sheffield, U.K.
4. Professor, Dept. of Civil Engineering, Aalborg Univ., Sohngaardsholmsvej 57, 9000 Aalborg, Denmark.