| 摘要 |
<p>PROBLEM TO BE SOLVED: To increase the filtration and dehydration drying rate of sludge drying beds, to remarkably reduce a production cost, to increase the effective surfaces of the sludge drying beds and to prevent the outflow of particulates. SOLUTION: The both flank water collection type filter device 21 is laid between the sludge drying beds 11 and 12 enclosed by a peripheral wall 3. The both flank water collection type filter device 21 is constituted by rectilinearly connecting a plurality of unit both flank water collection type filter devices. The unit casing of each unit both flank water collection type filter device has two broad-width sidewalls and two both narrow-width sidewalls. Numerous water permeable pores are formed at both broad-width sidewalls and communicating ports for draining are formed in the lowermost parts of both narrow-width sidewalls. Filter sand layers and ballast layers for water collection are formed successively from above in the respective unit casings. A water collection/drain pipe passing through the lower part of the both flank water collection type filter device 21 and the drain port of the peripheral wall 3 is installed in order to prevent the outflow of the particulates. One end of this pipe is provided with a flow rate control valve and the other end is closed.</p> |
