| 摘要 |
PURPOSE: To prevent the space between respective flat-membrane modules from being clogged with impurities (foreign matter) and to sufficiently clean the membrane surface of the module. CONSTITUTION: This treatment consists of an aerobic stage for the nitrification in an aerobic atmosphere and an anaerobic stage for the denitrification in an anaerobic atmosphere. In the aerobic stage, air is injected by a diffuser means from below a flat-membrane unit 25 consisting of plural flat-membrane modules 28 to circulate the water to be treated, and an upward flow is formed in the unit 25. In the anaerobic stage, the air injection is stopped, the water is circulated by an agitating means to form a downward flow in the unit 25. The upward flow and downward flow are alternately formed in the unit 25, and the space between the modules 28 is not clogged with impurities (foreign matter). |
