Abstract: In grid-type aeration systems with diffusers mounted and spaced longitudinally along air distribution conduits that are submerged in wastewater and secured to and above the floors of aeration tanks, such conduits are provided with couplings having first and second matingly compatible coupling sections of synthetic polymeric material adapted for relative rotation with respect to each other, at least one locking projection having a fixed position with respect to one of the coupling sections, and a locking receptacle array including locking receptacles having a fixed position with respect to the other coupling section. The projection and receptacles are relatively moveable in the coupling for motion from a non-engaged condition to an engaged condition during make up of the coupling.

Abstract: This disclosure relates to aeration, especially biological treatment of wastewater with fine pore diffusers and in situ cleaning of these diffusers with liquid and/or gaseous cleaning fluids supplied to the diffusers through cleaning fluid channels that respectively have separate and direct connections to plural diffusers. Aeration and cleaning of fine pore diffusers is described in which cleaning fluid is conducted from a source of such fluid to a multiplicity of diffusers via a flow path which is separate from a flow path which conveys aeration gas to the diffusers. Methods of fabricating aeration gas distribution assemblies are also disclosed. One such method involves securing to an aeration gas distribution conduit at least a portion of a cleaning fluid distribution channel which includes one or more cleaning fluid distribution conduits and further includes connectors coupled to the cleaning fluid distribution conduits.

Abstract: This disclosure relates to aeration, especially biological treatment of wastewater with fine pore diffusers and in situ cleaning of these diffusers with liquid and/or gaseous cleaning fluids supplied to the diffusers through cleaning fluid channels that respectively have separate and direct connections to plural diffusers. Aeration and cleaning of fine pore diffusers is described in which cleaning fluid is conducted from a source of such fluid to a multiplicity of diffusers via a flow path which is separate from a flow path which conveys aeration gas to the diffusers. Methods of fabricating aeration gas distribution assemblies are also disclosed. One such method involves securing to an aeration gas distribution conduit at least a portion of a cleaning fluid distribution channel which includes one or more cleaning fluid distribution conduits and further includes connectors coupled to the cleaning fluid distribution conduits.

Abstract: Cleaning of multi-pore diffusion elements in place with cleaning gases while submerged in liquid media by applying said elements in improved gas cleaning apparatus. Such apparatus may for example include diffusion element retaining rings or other retaining devices, positioned at the peripheries of the respective elements, for securing them in gas-tight relationship with their respective plenums for preventing escape of treating and cleaning gas. Another aspect of the apparatus includes diffusers having diffusion elements with upper and lower surfaces bounded by porous peripheral sides, said diffusers also including apparatus for preventing escape of air through the element sides. In another embodiment of diffusers with diffusion elements having upper and lower surfaces bounded by peripheral sides, there are plenums comprising gas tight enclosures that enclose these lower surfaces and that include upstanding walls facing and adjacent to said sides.

Abstract: Cleaning of multi-pore diffusion elements in place with cleaning gases while submerged in liquid media by applying said cleaning gases intermittently or continuously to said diffusion elements between predetermined limits of operating pressure and flow through flow regulation means and plenums for the respective diffusion elements.

Abstract: A swing diffuser apparatus for gas diffuser systems for liquid treatment is disclosed in which an array of diffusers (50) is movable between a deeply submerged, essentially horizontal operating position, a shallowly submerged, essentially horizontal operating position, and a fully exposed, substantially upright position at the edge of the container for the liquid. An articulated hanger arm linkage (22, 24, 26, 30, 32, 52, 54) rotates the array to achieve these positions as the linkage folds and unfolds.

Abstract: Gas diffusion elements, formed of a body of solid particles which have been shaped, pressed and rendered coherent by bonding or sintering in a compacted form having pores, are disclosed. Said elements include a peripheral, annular zone of relatively small proportions having lesser permeability, greater density or lesser height than at least a portion of the remainder of the element. In accordance with the invention, a boundary zone is provided adjacent to and inwardly of the peripheral zone, in which boundary zone there is a progressive increase, continuous or step-wise, in the apparent volumetric compression ratio of the element, in the direction of the pheripheral zone, or towards a vertical surface which is near the periphery of the element. Such element may provide improved gas, e.g. oxygen transfer efficiency and therefore holds promise of improving the efficiency and economics of gas transfer processes, such as for instance treatment of sewage or other waste water with air, oxygen and/or ozone.

Abstract: Gas diffusion elements, formed of a body of solid particles which have been shaped, pressed and rendered coherent by bonding or sintering in a compacted form having pores, and having an enhanced apparent volumetric compression ratio in a central zone and in a boundary zone thereof, are disclosed. Such elements have a generally horizontal portion including an upper gas discharge surface having a bubble release pressure in water, by a test disclosed herein, in the range of about 2 to about 20 inches of water. Among the preferred embodiments is an element whose gas discharge surface has the property that its coefficient of variation is not greater than about 0.25, based on the values of bubble release pressure at a plurality of points over said surface. Such elements may provide improved gas, e.g. oxygen, transfer efficiency, and therefore hold promise of improving the efficiency and economics of gas transfer processes, such as for instance treatment of sewage or other wastewater with air, oxygen and/or ozone.

Abstract: Gas diffusion elements, formed of a body of solid particles which has been shaped, pressed and rendered coherent by bonding or sintering in a compacted form having pores, and having an enhanced apparent volumetric compression ratio in a central zone thereof, are disclosed. Such elements have a generally horizontal portion including an upper gas discharge surface having a bubble release pressure in water, by a test disclosed herein, in the range of about 2 to about 20 inches of water. Among the preferred embodiments is an element whose gas discharge surface has the property that its coefficient of variation is not greater than about 0.25, based on the values of bubble release pressure at a plurality of points over said surface. Such elements may provide improved gas, e.g. oxygen, transfer efficiency, and therefore hold promise of improving the efficiency and economics of gas transfer processes, such as for instance treatment of sewage or other waste water with air, oxygen and/or ozone.

Abstract: Drop-back of solids into the drum pool of a rotary microscreen is reduced by applying a limited gas pressure differential across an unsubmerged portion of the screen cloth. The pressure is not for the purpose of increasing the driving force, .DELTA.H, of the liquid passing through the cloth. For purposes of this disclosure, .DELTA.H is the pressure differential existing across the screen below the surface of both the drum pool and tank pool. In fact, assuming other factors remain equal, application of a gas pressure differential to an unsubmerged portion of the screen cloth, with consequent reduction in drum pool suspended solids concentration, will normally reduce .DELTA.H even though the gas pressure also acts on the surface of the drum pool. More significantly, the invention enables operation of a microscreen unit at increased flow capacity at a given .DELTA.H. Whatever pressure is applied, there will be some reduction of torque, bearing load and wear at any given .DELTA.H.

Abstract: An aeration system for a sewage treatment tank including headers having connectors longitudinally spaced along the header, the connectors being adapted to receive air diffusers; means supporting the header horizontally in a tank; and means for rotating the header on its axis to level the connectors.

Abstract: Filtration in an internal rotary filter system is improved by externally impacting the filter screen as it rotates with a programmed spray of liquid that is varied from a relatively low to a relatively high pressure. In certain instances, this programmed spray is controlled by an electric timer circuit so arranged that the high pressure spray is on for a period of time which does not too unduly burden the system with fluid, but which is sufficient period of time to prevent slime formation on the screen. This can for instance keep the screen free of slime when no germicidal agent (e.g. Cl.sub.2) is employed.

Abstract: An aeration system for a sewage treatment plant, including headers having diffuser connectors longitudinally spaced along the header, the connectors having nipples formed thereon which are welded to nipples formed on the header.

Abstract: Cleaning of multi-pore diffusion elements in place with cleaning gases while submerged in liquid media by applying said cleaning gases intermittently or continuously to said diffusion elements between predetermined limits of operating pressure and flow through flow regulation means and plenums for the respective diffusion elements.