Abstract: A liquid treatment system using gas flotation to separate suspended matter from liquid influent, including a flotation tank into which the liquid influent is fed through an inlet, an outlet conduit through which treated effluent is fed from the flotation tank, a separation conduit for feeding liquid to a bubble release point, means for pressurising the liquid in the separation conduit and dissolving gas in the pressurised liquid, wherein an energy recovery device is used for reducing pressure of the liquid before the bubble release point such that gas bubbles are released into the flotation tank for floating said suspended matter to a surface of the liquid in the tank, and wherein the energy recovery device supplies energy obtained through said pressure reduction of the liquid.

Abstract: A pressure exchanger for transferring pressure from a high pressure fluid to a low pressure fluid, including a housing and a rotor arranged for rotation within the housing, the rotor having at least one passage extending generally axially through the rotor, the passage having a first opening at one end and a second opening at another end, the openings being mutually spaced along the length of the rotor, the housing having a plurality of ports at one axial portion for communication with the first passage opening and a plurality of ports at another axial portion for communication with the second passage opening, wherein the first passage opening is directed substantially radially such that fluid is directed radially inwardly when entering the first passage opening and radially outwardly when exiting the first passage opening.

Abstract: A liquid treatment system using gas flotation to separate suspended matter from liquid influent, including a flotation tank into which the liquid influent is fed through an inlet, an outlet conduit through which treated effluent is fed from the flotation tank, a separation conduit for feeding liquid to a bubble release point, means for pressurising the liquid in the separation conduit and dissolving gas in the pressurised liquid, wherein an energy recovery device is used for reducing pressure of the liquid before the bubble release point such that gas bubbles are released into the flotation tank for floating said suspended matter to a surface of the liquid in the tank, and wherein the energy recovery device supplies energy obtained through said pressure reduction of the liquid.