1. Department of Environmental Science and Technology, Graduate School of Environmental Studies, Tohoku University, Aoba-ku, Sendai 980-8579, Japan, Research and Development Center, Tohoku Electric Power Co., Inc., Sendai 981-0952, Japan, Environmental Systems & Plant Headquarters, Hitachi Zosen Corporation, Kyoto 625-8501, Japan, and Water & Sludge Engineering Center, Environmental Systems & Plant Headquarters, Hitachi Zosen Corporation, Tokyo, 100-8121, Japan