Abstract: A self-cleaning valve for discharge of a pressurized dissolved air flotation aqueous treatment liquid from a high pressure reservoir to a low pressure body of liquid to be treated is provided. The valve includes a discharge head body adapted to be attached to a conduit supplied with pressurized treatment liquid which is provided with a central opening for discharge of a treatment liquid. The opening is controllable by means of a reciprocable cap positioned to reciprocate from a position whereon it restricts flow of liquid through the opening to a position wherein flow in unrestricted. The cap is attached to a reciprocable piston rod attached at its opposite end to a piston that is movable within an enclosed cylinder. The cylinder is provided with a port or opening on each side of said piston into which a source of pressurized air connectable to cause movement of the piston and thus opening and closing of the valve by selectively directing the flow of said pressurized air to either side of the piston.

Abstract: The improved high pressure oxygen-saturated water treatment apparatus of the present invention functions to provide super-saturated oxygen treatment to waste water for purification thereof. The apparatus includes a pressurized treatment tank having a substantial longitudinal dimension, with a chamber separation plate forming two interconnected chambers in the tank. An input conduit for flowing waste water into the first chamber of the tank is provided. An oxygen input conduit is connected to the tank for providing oxygen-containing gas under substantial pressure within the tank. An oxygen output conduit is also disposed on the tank for receiving the oxygen-containing gas from the tank to form a pressurized oxygen-containing stream.