| 摘要 |
<p>PURPOSE:To maintain the purifying function of a channel for a long period by preventing an extending conglomerate layer from clogging with sludge and the like. CONSTITUTION:A filter member 11 comprises suspended materials such as foaming styrene, wood chips, hollow glass balls, plastic balls. Therefore, the filter members 11 undergo the effect of water flow and are rubbed with each other, so that sludge adhering to the filter members 11 gradually falls off from the surfaces of the filter members 11 and is accumulated in a sand pit 15. If the suspended filter members 11 are recovered from an opening part 17 by employing the transportation effect of water flow, cleaning work such as taking out the sludge accumulated in the sand pit 15 is facilitated.</p> |
