An apparatus for treating fluids having improved aeration efficiency and operational durability has an aerator, an impeller, and a liquid reservoir containing liquid to be treated. The aerator has: a motor rotating the impeller at a blade tip speed less than 1,100 inches/second; an air line having an outlet submerged in the liquid and an inlet adjacent to the motor; and a blower. The blower forces air through the air line to the air line outlet. The impeller two blades extending radially from the hub. Each blade has: a low drag, pressure equalized foil shape absent of rake; a leading edge extending from the hub tangentially; a 0.47-0.55 impeller EAR; 0.59-0.87 Pmean/D; progressive pitch distribution based on radius where from 50% R and out is constant and from 50% R to the hub is reduced; and 60-75 degree skew with a linear distribution from 50% radius to blade tip.

A device for gassing a liquid, including a rotor, which is driven to rotate and has multiple vanes for conveying the liquid, and a stator, which surrounds the rotor and has a plurality of flow channels, which each extends starting from a radially inner inlet opening adjacent to the rotor through the stator to a radially outer outlet opening and are delimited along their length by side walls, bottom surfaces, and top surfaces and can be acted on with liquid by the rotor in the region of the inlet opening, wherein between the inlet opening and the outlet opening, the side walls and/or bottom and top surfaces of the flow channels have a multitude of gassing openings, which can be acted on with compressed gas from a compressed gas source in order to introduce this gas into the flow channels. A corresponding method for gassing a liquid is also disclosed.

A rotor for use in a slurry separation flotation cell having a tank within which the rotor is contained. The rotor has a shaft that has a conduit adapted to communicate a fluid, preferably a gas such as air, therethrough. The rotor also has impeller blades extending radially from the shaft and a baffle adjacent the bottom of the impeller blades. The baffle extends from an end of the shaft to at or near an outer edge of the impeller blades, directing the gas to the outer edges of the impeller blades for dispersion into the slurry. The rotor is located adjacent a floor of the tank and, in use, draws slurry downwards into the impeller portion and forces it outwards with the gas being mixed therein.