METHOD OF TREATING WASTE WATER

摘要

1495852 Aerating liquids BASF AG 29 Jan 1975 [30 Jan 1974] 3841/75 Heading B1C In an activated sludge aeration process a jet of liquid at a momentum density (i.e. the product of the mass flow per unit time and velocity, per unit area) of 103 to 104 N/m2 is ejected from one or more nozzles, each having separate orifices for liquid and oxygencontaining gas, located adjacent the bottom of the reservoir, setting up momentum exchange with the mixture of waste water and activated sludge moving more slowly through reservoir at a momentum density of 50 to 103 N/M2, and causing a circulation in the vertical plane. In Fig. 1 an aeration ditch 1 has a central vertical partition 2 with nozzles 6 each having an associated impulse exchange tube 7 close to the partition and to the bottom of the ditch. The nozzle is supplied with air under pressure through a pipe 9 and with recirculated water/sludge mixture through a pipe 12. Due to the asymmetrical position of the nozzles the discharge 16 therefrom causes a helical flow of the liquid in the ditch. The nozzles may be inclined to the horizontal or vertical. Recirculated liquid may also be sprinkled on the surface from nozzles 18 to destroy foam. In another arrangement, (see Fig. 4, not shown) two nozzles may be placed at opposite ends of a diameter of a cylindrical tank. In a further arrangement (see Fig. 5, not shown) there may be two or more coaxial tanks (21, 22) having a bridge (25) rotatable about their axis and carrying a nozzle for each tank; flow through the tanks may be in parallel or series.