1. Research Associate, Dept. of Biological System Engineering, Washington State Univ., Pullman, WA 99164-6120. E-mail: bswang@wsunix.wsu.edu
2. Professor, Dept. of Biological System Engineering, Washington State Univ., Pullman, WA 99164-6120. E-mail: chens@wsu.edu
3. Director, State of Washington Water Research Center and Associate Professor, Dept. of Civil and Environmental Engineering, Washington State Univ., Pullman, WA 99164-3002. E-mail: meb@wsu.edu
4. Professor, Dept. of Civil and Environmental Engineering, Washington State Univ., Pullman, WA 99164-2910. E-mail: yonge@wsu.edu