| 摘要 |
<p>PURPOSE: To provide a waste water treating method capable of executing nitrification and denitrification treatments of waste water in one treating tank, capable of making a device compact and also reducing a nitrogen component in water to be treated. CONSTITUTION: Air is aerated into a treating tank 12 in a state in which a carrier 24 on which at least nitrifying bacteria is immobilized and an activated sludge 22 are allowed to coexist in the treating tank 12, and the carrier 24 and the activated sludge 22 are brought into contact with waste water while fluidizing in an aerobic state. Then, after stopping aeration, an inside of the treating tank 12 is deaerated while stirring the inside of the treating tank 12 so that the carrier 24 is allowed to settle and the activated sludge 22 is floated by using a difference of a specific gravity of the carrier 24 and the activated sludge 22 to brought the activated sludge into contact with a nitrifying liq. in an anaerobic state. Then, the nitrification treatment and an oxidation.denitrification treatment are executed more than one time in accordance with a water quality of waste water in one treating tank 12.</p> |
