| 摘要 |
<p>PURPOSE:To prevent the outflow of granular media to the outside of the system surely by settling and separating the granular media stuck with the microorganisms biologically treated water then conducting the separated water to filtration stage using granular filter media and capturing the media stuck with the microorganisms. CONSTITUTION:Raw water 4 is flowed into a biological treatment tank 1, where BOD is removed by the microorganisusm stuck on the surfaces of sand and suspended microorganisms. Thence, in a settling and separating part 5, the sand of good settling characteristic picking up the microorganisms at just a small amt. is settled and separated. The sand of degraded settling characteristic by picking up a large amt. of the microorganisms and suspended SS are entrained by biologically treated water 6' and are flowed out through an outflow pipe 6. Further, the water 6' is flowed into the packed bed 7 formed of anthracite, and when the amt. of capturing of the sand stuck with the microorganisms increases, a pump 9 is started to backflow the water out onto the upper part of the bed 7 and this water is recycled to the tank 1 through a return pipe 10.</p> |
