Abstract: An apparatus for introducing gases in the form of fine bubbles into a fluid is described, in which a diffuser pipe for a perforated distributor hose is mounted on a gas supply pipe. The diffuser pipe is constructed in one piece, extends transversely across the gas supply pipe, and is attached to the same by means of clamping elements. An opening for the passage of the gas is provided between the diffuser pipe and gas supply pipe. A pair of plugs positioned in the diffuser pipe define a flooding chamber at each end of the pipe and a gas-carrying chamber positioned medially therebetween. The apparatus is particularly suitable for the aeration of activation tanks for waste water.

Abstract: A process for physically and biologically purifying sewage. A combination filter-biofilter containing a bed of artificially aerated filler material is used. The sewage is preliminarily clarified and distributed evenly over the filler material and is caused to flow through the latter for a limited time until the sewage has coated the surfaces of the filler material with sludge and microorganisms to an extent that the passage of air through the filler bed is substantially decreased because of encrustation of the interstices of the filler material. At this point the flow of sewage through the filler material is halted and the bulk of the sludge is removed from the filler material by turning the same over with air. Then, the flow of sewage through the filler material is reinstituted.