A rotary gas bubble ejector has a fluid reservoir chamber having at a bottom end a fluid discharge opening and a shaft extending through fluid reservoir chamber in connection with a rotor plate. The rotor plate has an outer dimension greater than the outer dimension of fluid discharge opening and is positioned proximate bottom end of fluid reservoir chamber such that a fluid acceleration gap is formed. Rotation of the shaft and rotor plate initiates a fluid flow thereby generating a low-pressure zone within the fluid acceleration gap, wherein gas is discharged from the fluid reservoir chamber into the fluid acceleration gap. As the gas is expelled from the fluid acceleration gap, fluids, gas and liquid, are brought into contact producing micro-sized gas bubbles that are ejected into the body of liquid.

A device and method for injection of oxygen-rich gas into a body of liquid with oxygen recycling are disclosed. The device comprises a rotary hollow shaft vertically passing through a float partially immersed in the liquid, an impeller attached to the lower end of the rotary hollow shaft, a columnar structure, surrounding the rotary hollow shaft, mounted on the bottom side of the float and vertically extending into the liquid, a gas diffusion chamber formed by the columnar structure, the float and the liquid surface under the float, and a gas injection conduit passing through the float for delivering the oxygen gas into the gas diffusion chamber, wherein a vacuum is generated in the body of the liquid around the impeller when the impeller is driven to rotate, so that the oxygen-rich gas in the gas diffusion chamber is sucked into the body of the liquid and mixed therein.

In an apparatus for mass transfer between a liquid and a gas inside a rotor, the liquid is supplied to a center of the rotor and is driven outward by centrifugal force generated by rotation of the rotor, the gas surrounding the rotor is forced inward through the rotor by a pressure of the gas, counter to the liquid flow in the rotor, and the rotor has a plurality of passages lying in the plane of the rotor that begin at a center of the rotor and terminate at an outer circumference of the rotor. The passages are each filled with a packing that increases the area of contact between the liquid and the gas.

Aeration device includes a hollow casing having a motor therein; a mixing unit formed on front side of the casing and having a discharge hole formed in radial direction and an intake hole formed on front thereof; an impeller located inside the mixing unit and coupled to a driving shaft of the motor, the driving shaft extended to the mixing unit, so as to be rotated with the driving shaft, to generate flow in outward radial direction upon rotation, an air inflow unit having one side end located in front of the impeller and serving as an air inflow pipe for introducing air to the mixing unit; and an auxiliary intake unit located on front side of the impeller to be rotated with the driving shaft of the motor and inserted into the air inflow unit to allow fluid in the air inflow unit to flow backward upon rotation.

An aeration device includes a pipe, connection members and a first connection unit which is connected to the connection member. The first connection unit includes a first connector, a first connection part, a one-way member, a second connector, a turbine unit and a shell. When air enters into the pipe, the shell guides the air and liquid in the pound into the turbine unit via the second and third rooms so as to increase the mixing feature of the air and the liquid in the pound.