title: Comparison of polytetrafluoroethylene flat-sheet membranes with different pore sizes in application to submerged membrane bioreactor.
abstract: This study focused on phase separation of activated sludge mixed liquor by flat-sheet membranes of polytetrafluoroethylene (PTFE). A 20 liter working volume lab-scale MBR incorporating immersed PTFE flat-sheet membrane modules with different pore sizes (0.3, 0.5 and 1.0 μm) was operated for 19 days treating a synthetic wastewater. The experiment was interrupted twice at days 5 and 13 when the modules were removed and cleaned physically and chemically in sequence. The pure water permeate flux of each membrane module was measured before and after each cleaning step to calculate membrane resistances. Results showed that fouling of membrane modules with 0.3 μm pore size was more rapid than other membrane modules with different pore sizes (0.5 and 1.0 μm). On the other hand, it was not clear whether fouling of the 0.5 μm membrane module was more severe than that of the 1.0 μm membrane module. This was partly because of the membrane condition after chemical cleaning, which seemed to determine the fouling of those modules over the next period. When irreversible resistance (Ri) i.e., differences in membrane resistance before use and after chemical cleaning was high, the transmembrane pressure increased quickly during the next period irrespective of membrane pore size.
authors: Department of Chemical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan. nittami@ynu.ac.jp.
authors: Tadashi
authors: T
authors: Nittami
authors: Department of Chemical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan. d08ga638@ynu.ac.jp.
authors: Tetsuo
authors: T
authors: Hitomi
authors: Department of Chemical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan. k-mtmt@ynu.ac.jp.
authors: Kanji
authors: K
authors: Matsumoto
authors: Department of Chemical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan. naka1@ynu.ac.jp.
authors: Kazuho
authors: K
authors: Nakamura
authors: Corporate Research Division, Nippon Valqua Industries, Ltd., 2-2-2 Oyamagaoka, Machida, Tokyo 194-0215, Japan. t-ikeda@valqua.co.jp.
authors: Takaharu
authors: T
authors: Ikeda
authors: Corporate Research Division, Nippon Valqua Industries, Ltd., 2-2-2 Oyamagaoka, Machida, Tokyo 194-0215, Japan. y-setoguchi@valqua.co.jp.
authors: Yoshihiro
authors: Y
authors: Setoguchi
authors: Corporate Research Division, Nippon Valqua Industries, Ltd., 2-2-2 Oyamagaoka, Machida, Tokyo 194-0215, Japan. m-motoori@valqua.co.jp.
authors: Manabu
authors: M
authors: Motoori