GB205597A - Improvements in or relating to means for mixing and treating liquids - Google Patents

Abstract

205,597. Bicknell, R. H., and Honeysett, A. July 28, 1922. Plant; gravity-separation apparatus; aerating. -A single mechanical fluid-moving device, such as a scoop wheel, a paddle or an Archimedean screw pump, is used in a sewage circulation system to provide the necessary energy for the circulation, for aeration and mixing and for the return of activated sludge to the system. The sewage is delivered to preliminary sedimentation tanks b, c, Fig. 1, from which it passes over weirs j, and through an apertured diaphragm l and a pipe m to a cross-channel p connecting endless treatment channels n, o. Each of the treatment channels is provided with a fluid. moving device q and agitating arrangements s. A portion of the liquid is continually passing away through cross-channels p<1> and pipes t to settling-tanks u. Liquid is discharged from the settling-tanks over weirs v and through a pipe w, which may be provided with a gauge x. Sludge is continuously discharged from the settling- tanks, through a pipe z, part passing into a detritus pit g, whch also receives the settled matter from the tanks b, c, and part being delivered to a pit b<1>, from which it is returned to the treatment channels n, o, at points near the devices q where the pressure in the channels is low. The'channels are at this part so shaped as to produce a local increase of velocity resulting in a lowering of the liquid level. The agitating arrangements s may comprise plates or other flat surfaces which form passages divergent in one direction and convergent in another, so that the liquid on one side of the channel at the up-stream side of the device is at the down-stream end below the liquid which comes from the other side of the channel. Paddle wheels, having parallel or helical blades, and caused to revolve by the velocity of the liquid, may also be provided to agitate and aerate the liquid. Such paddle wheels may be mounted on displaceable bearings which can be inserted as desired at any part of the channel. The devices q may be scoop wheels having paddles with adjustable rubber edges. Fig. 3 shows a single endless treatment channel with multiple convolutions. It may be constructed on a horizontal surface and its width may vary, so that a constant liquid cross-section is maintained although the liquid head is lowered in the direction of flow.