| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the excess stripping of a biological membrane on the surface of filter media and the outflow of the filter media caused by the inflow of bubbles by providing a retaining part of a water to be treated for retaining the water to be treated for a prescribed time between a flow passage and an inflow pipe. SOLUTION: The water to be treated is passed through the flow passage 7, a put of which is opened to the air, the flow passage 7 follows the retaining part 6 and both are arranged so that the water level of the retaining part 6 is lower than the bottom surface of the flow passage 7 to form the difference of level. The water to be treated passed through the difference of level flows to fall down from the flow passage 7 to the retaining part 6. The flowing-in water to be treated is decreased in flow speed in the retaining part 6 and a time sufficient to remove the bubbles having such a size that causes the excess stripping of the biological membrane or the outflow of the filter media is given before the water to be treated containing bubbles 10 fold by catching the air reaches an inflow pipe 5. And since a partition plate is existed, the bubbles 10 are prevented from flowing-in to the inflow pipe 5 even when the water to be treated falling down from the flow passage 7 causes the partial turbulence of the water surface in the retaining part 6.</p> |
