| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a structure for bridging a water-passage plate for forming a filter bed by which a supporting rack and a presser bar are not needed, the partition wall is not deformed by soil pressure or water pressure, and the water- passage plate is easily detached. SOLUTION: The water-passage plates 4, 5 and 6 are laid over the two opposed faces 3a and 3b of the partition wall for dividing the inside of a septic tank. In this case, each of the water-passage plates consists of a set of plates A and B, recesses 11, 12 and 13 capable of detaining the water-passage plates are formed in the two faces 3a and 3b, and the plates A and B are fixed and not expanded when the water-passage plates are bridged over the partition walls 3a and 3b.</p> |
