activated sludge sewage cleaning method and device for implementing this process

摘要

1450612 Aerating liquids AIRCO INC 29 Oct 1974 [6 Nov 1973] 46806/74 Heading B1C Liquid (e.g. waste water) 12 in a tank 13 is introduced into an at least partially immersed vessel 11 as by an impeller pump 17, the level of the liquid in the vessel being depressed by oxygen-containing gas introduced under pressure at 29. The liquid falls by gravity over a weir 21 into a turbulent mixing zone 24 where it entrains gas, passes under a baffle 23 and over another baffle 27 into a quiescent zone 25 where it circulates; undissolved gas bubbles rise to the surface and are recycled to the mixing zone. Waste gas containing impurities may be vented intermittently or continuously through a vent 30 which may be valve controlled. Treated liquid leaves the vessel 11 through a flap valve 31 controlled by a rod 32, and through a nozzle 33 rotatable by a tube 34 and having a flap valve controlled by a rod 35, whereby sludge in the tank 13 may be agitated and circulated. The tube and rod 34, 35 are surrounded by a bubble trap and pressure relief device 37, 39. As shown, the vessel 11 is paired with a similar vessel 11', the impeller pump supplying both. The gravitational fall zone may be replaced by an eductor or other static gas-liquid mixer. In a modification. (Fig. 7, not shown) the vessel is a wholly immersed bell.