| 摘要 |
PROBLEM TO BE SOLVED: To provide a sand filter which can be assembled on site, easily conduct a maintenance of a sand layer, and easily recover muddy content removed from the sand layer. SOLUTION: A catchment material 12 having a self-retaining shape nature and permeability is arranged at the bottom of a container 11 having an opening 11a. The sand layer 13 for filtering water to be treated is formed such that sand fills the container 11 so as to cover the catchment material 12. A muddy content recovery part 15 forms a space 21 vertically extending in the container 11, so as to recover in the space 21 the muddy content 24 separating from the sand layer 13 due to air blown out into the sand layer 13 from an air blow-out means 14 and floating in a water layer 19 together with water. The lower portion of the muddy content recovery part 15 is buried in the sand layer 13, the upper portion is projected from the sand layer 13 so that water can be flown in the space 21, an openable/closable discharge port 22 at bottom of the container 11 communicates with the space 21, and the muddy content 24 recovered in the space 21 is discharged outside together with water through the discharge port 22. COPYRIGHT: (C)2007,JPO&INPIT
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