| 摘要 |
PROBLEM TO BE SOLVED: To provide a filtering method for stably keeping the discharge of a captured suspension over a long time and capable of enhancing a water recovery ratio. SOLUTION: When water to be treated containing the suspension is filtered using a pressure filter having a filter medium bed 2 filled with a filter medium, a stirrer 4 for fluidizing the upper part of the filter medium bed 2 and an intermediate water discharge pipe 6 provided above the filter medium bed 2, the suspension is captured in the vicinity of a filter medium surface layer in a filter process and, when filtering resistance increases, the filter medium bed is periodically washed by a process (a) for discarding water at an intermediate part from the pipe 6, a process (b) for introducing water and air from below within a range not fluidizing the filter medium bed 2 and rotating the stirrer 4 at a speed of 5-25 rpm and peeling the captured suspension from the filter medium to transport the same to the upper part of the filter medium bed 2, a process (c) for discarding water at the intermediate part from the pipe 6 and a process (d) for washing the filter medium bed 2 with water at a low flow sped within the range not fluidizing the filter medium bed 2 and rotating the stirrer 4 at a speed of 5-25 rpm to discharge the suspension and remaining air to the outside of the system. COPYRIGHT: (C)2003,JPO
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