| 摘要 |
<p>PURPOSE:To increase the activity of microorganisms by preventing decrease in dissolved oxygen in water throughout a cleaning water channel. CONSTITUTION:A shoal 21 is installed in the boundary part between the first pebbel layer 11 and the second pebbel layer 12 to make the depth of a part of a water channel extremely shallow so that a turbulent water flow is produced. The remarkable turbulence of water surface increases the air intake effect. Moreover, the turbulent water flow effect due to projections 22 fixed on the bottom of the shoal 21 and sheathing boards 23, 24 fixed on the boundaries between the shoal 21 and the respective pebbel layers 11, 12 contributes to the intake of oxygen in the air into the water of the river.</p> |
