To provide a filtration system to attain both uniform backwashing of a floating filter media layer and efficient backwashing at low cost.
The filtration system includes: a first filtration vessel having a first floating filter media layer, a first upper screen having a first aperture ratio, for supporting a floating filter medium above the first floating filter media layer, a first treated water inlet port arranged below the first floating filter media layer, a first backwash water supply disposed above the first upper screen, and a first backwash water draining means arranged below the first floating filter media layer; and a second filtration vessel having a second floating filter media layer, a second upper screen having a second aperture ratio, for supporting a floating filter medium above the second floating filter media layer, a second treated water inlet port arranged below the second floating filter media layer, an inflow shutoff mechanism adapted to shut off the inflow of treated water passing through the second treated water inlet port, a second backwash water supply disposed above the second upper screen, and a second backwash water draining means arranged below the second floating filter media layer. The first aperture ratio is smaller than the second aperture ratio.
NAKAYAMA YOSHIHIKO
| JP2004290752A | 2004-10-21 | |||
| JP2005270931A | 2005-10-06 | |||
| JP2007038092A | 2007-02-15 | |||
| JP2003136088A | 2003-05-13 |
| WO2002081050A1 | 2002-10-17 |
Kazuyuki Tomita
Yuta Terashima
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