Patent ID: 8298418

Claim:
An installation comprising: an inflow channel ( 2 ) for a liquid stream to be treated, a descending vertical pipe ( 3 ) forming a shaft toward an end of the inflow channel, the descending vertical pipe being directly joined, at a bottom of the vertical pipe, to an approximately horizontal pipe ( 4 ), pumping means ( 11 ) being provided for withdrawing a tapped-off fraction of the liquid stream upstream of the descending vertical pipe and for directing the tapped-off stream toward a mixing assembly ( 14 ), receiving a gas—air and/or oxygen—laden with ozone; and producing a two-phase trapped off stream, wherein: the mixing assembly ( 14 ) is placed at the top of a vertical injection tube ( 16 ) which is immersed in the descending vertical pipe ( 3 ), which pipe is free of any obstacles so that a descending vertical flow ( 3 a ) forms a continuous liquid column; and the vertical injection tube ( 16 ) includes, near a lower end, a static mixer ( 19 i ) for keeping bubble diameters below a predetermined value, and its lower end includes at least one opening ( 16 a ) for reintroducing the two-phase tapped-off stream into the descending vertical flow in the form of at least one jet ( 25 ) having a downwardly vertical velocity component (V Z ), the length of the injection tube ( 16 ) and the outlet opening ( 16 a ) of the jet both being provided so that the reintroduction takes place below a liquid height (H) and with a downwardly vertical velocity component (V Z ) that are sufficient for the gas bubbles to be entrained downward, without them rising in the descending vertical flow of the liquid stream.