| 摘要 |
<p>PURPOSE:To enhance the capability to treat water and the capability to absorb variations in load and prevent sludge separation efficiency from being lowered, by a method wherein the amount of an activated sludge taken out to the exterior of a treating system is so adjusted that the average residence time of the activated sludge in the treating system is made to be 10-30 days. CONSTITUTION:Water to be treated is circulated through a falling passage 1, a rising passage 2 and a pump line 3 while supplying it through a supply passage 4, and simultaneously, oxygen gas is dissolved into the water to conduct the treatments of the water for lowering the biological oxygen demand (BOD), for denitrification and the like through the action of a high-concentration activated sludge under the supply of a large amount of oxygen. In addition, the average residence time (in days) of the activated sludge in the system, i.e., the total amount of activated sludge in the system divided by the sum of the amount of sludge taken out into a storage tank 11 per day and the amount of sludge flowing out into a water discharge passage 12 per day, is controlled to be 10-30 days by operating an adjusting valve 13.</p> |
