1. Research Student, Dept. of Environmental Engineering, Univ. Teknologi Malaysia, 81310 Johor, Malaysia.
2. Senior Lecturer, Dept. of Environmental Engineering, Water Research Alliance, Univ. Teknologi Malaysia, 81310 Johor, Malaysia.
3. Postdoctorate, Dept. of Environmental Engineering, Univ. Teknologi Malaysia, 81310 Johor, Malaysia (corresponding author).
4. Professor, Dept. of Environmental Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.