GB550926A - Improvements in or relating to means for the purification of impure liquid or semi-liquid matter - Google Patents

Abstract

550,926. Treating sewage etc.; filters. COOMBS, J. A. July 26, 1941, No. 9506. [Classes 46 and 111] A plant for the purification of impure liquid or semi-liquid matter comprises a filter bed 13 consisting of layers of hollow bodies 59 having apertured walls over which the liquid &c. mixed with activated sludge is distributed by spraying devices 26 on conduits 25, air being drawn, or forced, through the bed by suction devices, or blowers, connected to conduits 31. Preferably alternate layers of hollow bodies of substantially spherical or inverted pear-like form, as shown in Figs. 3 and 5, are employed. The bodies may be made of cast-iron or the material known under the Registered Trade Mark "Bakelite" and the inner and outer surfaces fitted or otherwise roughened. Layers of solid bodies may be interposed between some or all of the layers of hollow bodies. Liquid collected in a sump 27 passes through a conduit 28 to a sump 29 from which it is raised by an air-lifting device 35 to a channel 36 leading to a settlement tank 14, purified liquid passing over a weir 37 to an outlet channel 38. Sludge in the tank 14 is collected, as by scrapers constructed as described in Specification 514,662, in a sump 40 and is discharged by a pneumatic ejector 41 to a re-activation tank, from which superactivated sludge is conveyed by a conduit 43 to an 71 injector 19. The sludge is mixed with air and impure liquid &c. in the injector 19 and delivered to a tank 18 from which it is raised by an air-lift device 20 to a tank 21 leading to the conduit 25. The impure liquid &c. is supplied by a pipe 17 from a preliminary crude sewage treatment plant, which may be constructed as described in Specifications 514,627 and 542,008. The filter may be made as a mobile unit for use with mobile settlement and re-activation tanks for purifying polluted water for camps &c.