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: A sewage aeration system comprising a header pipe, plenums of synthetic thermoplastic or thermoset resin with side walls inclined upwardly and outwardly to diffusion element support means, generally horizontal diffusion elements free of through-holes other than air diffusion pores, retaining means securing the elements about their peripheries to the plenums, sealing means adjacent the peripheries of the diffusion elements and airflow regulator members which terminate in the plenums beneath the horizontal diffusion elements.

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.