An apparatus for treating fluids such as waste streams with improved aeration efficiency and dual function operation has a blower-assisted aerator, an impeller, a baffle structure circumscribing an air line that includes a first baffle and a second perforated baffle downstream from the first baffle, and a liquid reservoir containing a liquid. The impeller is fully submerged, and located upstream of the fully submerged baffle structure. A fully submerged air outlet is located downstream of the baffle structure, preferably in close proximity to the perforated baffle. When the blower is stopped and the impeller rotating, the baffle structure prevents aspiration into the liquid. In some embodiments, the baffle structure is removably affixed to an air outlet from the blower-assisted aerator, and so may be applied to pre-existing blower-assisted aerators. In some embodiments, one or both of the first and second baffles may resemble flat, domed, cupped, or hemispherical washers.

A pivotal rigid vortex shield configured for use in combination with a propeller-type aerator has a vortex shield, and a rigid support affixing the vortex shield to a support system. The support has a horizontal support bar with at least two cross arches, first and second vertical pivot and locking members, and a top arch affixed between. A pintle couples the support to vortex shield, and defines a pivotal axis about which the vortex shield is configured to rotate. A locking member may be at least one quick release pin that in an operational configuration simultaneously passes through at least a portion of at least one of the vertical pivot and locking members and at least a portion of the vortex shield support to prevent rotation of the vortex shield about the pintle. In a service configuration the pin is removed to permit the vortex shield to rotate.

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.

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.

An apparatus for treating water in a reservoir includes a funnel. A support assembly supports the funnel in a lengthwise upright orientation when the funnel is submerged. A water moving arrangement is arranged to move water through the funnel in a direction from an inlet at an upper end of the funnel towards an outlet at lower end of the funnel.