Aspects of the present disclosure provide various apparatus and methods. In some embodiments, an apparatus is provided for mixing a gas with a liquid. The apparatus may include a pipe having two ends. The pipe may provide a main fluid path and may have an interior surface having a first groove. The apparatus may also include a helical vane disposed inside the pipe. The vane may have a first projecting tongue that engages the first groove. The apparatus may also include a gas injection port on the pipe adapted to inject gas into the fluid path upstream of the helical vane. In some embodiments, the helical vane may be a 3D printed component.

A bubbler apparatus may include a container, a lid, a sealing member and at least one routing member. As the lid is tightened to the container and the sealing member is compressed, the routing member(s) does not contact the inside bottom surface of the container. Instead, there is a small gap between the routing member and the bottom surface of the container. The routing member may compress the substance in the container that the gas is saturated with or may slice through the substance.

Equipment for massive dissolution of gases in liquids via the formation of thin liquid films and the exchange of gases with said films. The equipment provides movement of liquids over great distances via the upward movement of bubbles therein. The equipment can alter the direction of the flow of water, said aspect being useful for the recovery of liquid bodies. In addition to providing a high rate of dissolution of gases in liquids, the equipment is very energy-efficient and has a very large volumetric capacity, thereby being useful for the preservation and/or recovery of liquid bodies, being able, in certain applications, to operate in an energy-autonomous manner. The equipment can be used in situations where energy-efficient dissolution of gases in liquids is desired, such as the preservation and/or recovery of liquid bodies; processes for preserving and/or improving the productivity of aquaculture systems; wastewater treatment systems; and the fixation of gases.

A valve contact tray for use in a mass transfer or heat exchange column and having a plurality of fixed or moveable valves distributed across a tray deck of the contact tray. Each of the valves includes an opening in the tray deck, a valve cover connected to attachment legs, and a weir surrounding the opening. The valve cover is wider than and extends outwardly beyond the underlying opening in the tray deck and has a perimeter region that extends downwardly. A louvered vent opening may be provided in a downstream one of the attachment legs.