PURPOSE: To permit deep layer filtration in the filter layer on the raw water side possible and to provide high performance for removing of suspended solids with filter media on the treated water side by forming the filter layer on the raw water side vulnerable to segregation of suspended solids into the filter medium construction of larger grain sizes as compared to the filter layer on the treated water side.
CONSTITUTION: The raw water supplied from a raw water supply pipe 1 is admitted through a screen 3 on the raw water side into a filter layer 12 on the raw water side by a difference in head between the raw water and the treated water. While the raw water passes here, the greater part of the suspended solids are captured in the filter layer while dispersing therein. The water which is decreased of the concn. of suspended solids is subjected to a high degree of removal of suspended solids by filter media of small grain sizes in a filter layer 10 on the treated water side. This water flows out into a treated water tank 8 through a screen 7 on the treated water side. On the other hand, the filter media of large grain sizes are supplied in the layer 12 with a partition plate 11 for filter media as a boundary. The filter media capturing the suspended solids are mixed in the bottom parts of the filter layers and are discharged at a constant rate into a used filter medium layer 6 by means of a rotary feeder 4.
HIRASAWA TERUTAKA
YOKOYAMA TOSHIYUKI
KAMATA HIROSHI
NAGASAWA ATSUO
MOMO MORIO
MURAKAMI TATSU
SUMITOMO HEAVY INDUSTRIES
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