Treatment of liquid

In a process for providing a dissolving within a body of liquid at generally atmospheric pressure a gas which is sparingly soluble in the liquid by removing a portion of the liquid as a stream of liquid, and pressurizing the stream of liquid during introduction of the sparingly soluble gas into the stream of liquid prior to introduction of the pressurized stream of liquid back into the body of liquid, the improvement which comprises the steps of:

• (a) passing the pressurized stream of liquid through a conduit and introducing the gas into the conduit under turbulent conditions as a substantially inner gas phase of undissolved gas bubbles at a rate to provide in the pressurized stream 100% to 1500% by weight of undissolved gas in excess of the equilibrium saturation value of said gas in said liquid at the pressure of said pressurized stream to establish a gas-in-liquid dispersion comprising finely dispersed bubbles of undissolved gas which are carried within the pressurized stream of liquid in the conduit without any significant formation of a discrete vapor phase or significant dissolution of said dispersion in the conduit;
• (b) maintaining the rate of flow of the liquid in the conduit at least at a minimum limiting value at which the bubbles of undissolved gas comprising the gas-in-liquid phase carried in the pressurized stream do not combine to form a significant vapor phase in the conduit;
• (c) maintaining the excess of the equilibrium saturation of (a) in the conduit until immediately prior to introduction of the pressurized stream of (a) back into the body of liquid;
• and
• (d) introducing the pressurized stream containing the finely dispersed bubbles of undissolved gas of (a) as maintained in (b) and (c) back into the body of liquid under turbulent conditions so that the finely dispersed bubbles of undissolved gas are sheared into even finer bubbles which either dissolve or are dispersed as a generally discrete gas-in-liquid phase within the body of liquid before any significant amount of dispersed gas reaches the surface of the body of liquid.