| 摘要 |
<p>PURPOSE:To reduce the size over the entire part of the treating device and to well maintain the quality of treated water by using a 1st tank as a settling stage and a 2nd tank as an aeration stage, when the volume of water increases, then by admitting the biologically treated water from the 2nd tank to the 1st tank, discharging the supernatant water and returning the settled and thickened sludge to the 2nd tank. CONSTITUTION:The aeration of the 1st tank 36A is suspended and the settling stage is put into operation when the inflow sewage exceeds a prescribed water level HWL. The 2nd tank 36A continues the aeration treatment in succession. While the biologically treated water after the aeration treatment is admitted from the 2nd tank 36B into the 1st tank 36A, the settling and separating of the sludge are executed. The supernatant water thereof is discharged to the outside to prevent the overflow of the sewage from the 1st tank 36A and the 2nd tank 36B. The clean treated water is obtd. in this way without increasing the size of the batch treating tank 36 even if the volume of the water increases. The thickened sludge settled in the 1st tank 36A is returned to the 2nd tank 36B and, therefore, the decrease in the concn. of the activated sludge on the aeration stage side is prevented and the degradation in the adsorption treatment efficiency by the microorganisms of the sewage is prevented.</p> |
