| 摘要 |
<p>PURPOSE: To simply form a fixed bed only by inserting the support forming the fixed bed and a water passing plate into an outer tank from the upper end opening part thereof without fixing them to the outer tank and to simply replace or replenish a floatable filter material from the upper end opening part of the tank. CONSTITUTION: In a biological filter tank, sewage is allowed to flow to a fixed bed packed with a floatable filter material 25 with specific gravity of 1 or less as ascending or descending flow to be subjected to purifying treatment. A lower water passing plate 4 is placed on the support 2 placed on a tank bottom 3 and the supports 5 supporting an upper water passing plate 9 are vertically provided on the lower water passing plate 4. Subsequently, the floatable filter material 25 is charged and the upper water passing plate 9 is placed on the supports 5 and, finally, the suppressing member 10 suppressing the flotation of the upper water passing plate caused by the buoyancy of the floatable filter material 25 is attached to the upper part of the upper water passing plate 9 through an outer tank 1. The space between the upper and lower water passing plates is packed with the floatable filter material 25 to form the fixed bed 8.</p> |
