Abstract: Vat and sulfur dyes are recovered from caustic wash water containing oxidized dye by adding ions of aluminum, chromium, ferric iron, lead, or tin and reducing the pH of the wash water to between 6 and 6.8 and separating the precipitate formed for recycling into the dyeing process.

Abstract: A liquid aeration device comprises a receiver chamber having bottom and side walls and arranged to receive liquid to be aerated and including an aerator wall in which orifice means is formed through which water to be aerated flows, a vertically disposed downcomer conduit atop which said receiver chamber is mounted and which is arranged to receive water by free fall flowing through said orifice means and downwardly into said downcomer and a vertically disposed riser conduit concentrically arranged about said downcomer conduit with its lower end in communication with the lower end of said downcomer conduit.

Abstract: A waste treatment and solids separating system includes a reservoir, feed means for causing waste liquid to flow into said reservoir and outwardly therefrom, ejector means disposed in said reservoir and in communication with atmosphere, pump means for withdrawing liquid from said reservoir and for forcing such withdrawn liquid through said ejector means in one general substantially horizontal direction to aerate said liquid from atmosphere, sensor means for sensing the concentration of oxygen dissolved in the liquid in said reservoir, control means for varying the rate at which said pump means forces liquid through said ejector means in coordination with variations in oxygen concentration in said liquid together with tube settler means disposed in said reservoir and having substantially vertically disposed juxtaposed parallel tubes for effecting settling of solid materials due to a ricocheting path of flow of the liquid which flows generally upward through the tubes caused by the combined action of said feed

Abstract: A liquid aeration device includes a head box having a bottom wall, a pair of spaced side walls interconnected with the bottom wall, and a pair of spaced transverse walls interconnected with the side and bottom walls to form a receiver chamber into which liquid to be aerated is fed and from which such liquid passes through orifice means formed in one transverse wall of the head box from whence the liquid by free fall passes through an entry chamber and enters a vertically disposed downcomer conduit interconnected at its bottom with a pressure chamber to which a vertically disposed riser conduit is also connected.

Abstract: Colloids are precipitated from an aqueous suspension by electrolysis techniques in which a flocculation cell is provided with a soluble anode formed preferably of multi-valent material and wherein the cathode comprises a metal cylinder having an inlet at one end and an outlet at the other end and in which the anode is coaxially disposed in insulated relation to the cathode so that an aqueous suspension may be caused to flow through the cell in such manner as thoroughly and systematically to wash the inner surface of the cathode and the outer surface of the anode by following a generally helical path which inhibits formation of large clusters of hydrogen and oxygen gas established by the application of an electric potential across the cathode and anode. The pH of the aqueous solution must be controlled at a substantially neutral value and the anode preferably is formed of soluble aluminum, iron, magnesium or other multi-valent metal.