| 摘要 |
<p>PURPOSE:To stabilize the function of removing soluble nitrogen by composing a water washing mechanism of a circulating mechanism in which reserved treated water overflowing from a reaction vessel is circulated to the bottom of the reaction vessel and recovering the surface of a bismembrane soon after a filter bed being washed with water. CONSTITUTION:When a filter bed is washed with water, a pump 15 with a flow rate Q2 is stopped, and a pump with a flow rate Q1 is operated to form a circulating flow composed of a water receiving vessel 19, a pump 25, a pipe b, and the water receiving vessel 19. For example, the ratio Q2/Q1 is set to be 1.5-3.0, and suspended solid (SS), which swells a filter medium and is deposited in a space 50, is released into the circulating flow. The pump 25 is then stopped, a valve 30 is opened to empty the water receiving vessel 19, and a valve 29 is opened to empty a reaction vessel 10, finishing the circulation with the actuation of a level sensor 32. After the sludge being discharged, a pump 15 is started to restore a normal operation. Then, the remaining suspended solid (SS) is mixed into a filter bed 12, and the surface is generally recovered within one hour.</p> |
