| 摘要 |
<p>In the present invention, there is disclosed a waste water bio-aeration process in which waste water being supplied into an activated sludge tank are subjected to preliminary purification and then supplied along with sludge into a settling tank in which sludge settles on the bottom thereof. The preliminary purified water ascends toward an overflow onto a flooded sand filter, flows therethrough into a collecting main at the sand filter bottom. From the collecting main, the clean water is then expelled due to hydrostatic overpressure into a discharge. In case of drop of waste water level in equalizing tank below a preset minimum level, purification of the sand filter by aeration takes place and simultaneously pumping of waste water from the equalizing tank into the activated sludge tank and aeration thereof is interrupted. Aeration of the sand filter takes place until level of waste water in the equalizing tank rises up to the preset value. At that instant, pumping of waste water into the activated sludge tank and aeration thereof is restored.</p> |
