| 摘要 |
PURPOSE:To obtain treated water having good quality having a value of BOD and SS each specified value or below in a short time by flocculating org. filthy water by adding an inorganic flocculant and stirring the mixture, separating the liquid phase from the solid phase primarily and transporting the liquid phase to a filtration tank, and treating with activated sludge again. CONSTITUTION:Org. filthy water is introduced into a stirring tank 1, mixed with an inorganic flocculant such as PAC injected quantiatively thereinto and stirred with a rapid stirring device 2, then fed to a flow stirring tank 3 where it stirred slowly with a slow stirring device 4. Flocs of SS, colloidal matters, and P, etc., are grown, and allowed to contact with fine bubble group from a reduced pressure bubble generating apparatus 8 in a floating separation tank 5. Thus, a floated sludge layer 10 is formed by the floc floated by the effect of adhered bubbles, and discharged by a discharging device 9. The water is then introduced into a biological filtration tank 14 with a pump 13 through a water level adjusting tank 11 and a primary water storage tank 12, and then treated with aerobic microorganisms deposited to a filtration layer 15 on a supporting gravel layer 16 and air from an air diffusing pipe 18. By this process, satisfactory treated water having improved value of BOD and SS each specified level or below is obtd. is a short time. |
