A gassing unit for bubble-free introduction of process gas into a liquid in a reactor, wherein the gassing unit includes at least: first and second spaced apart gas receiving chambers, the two gas receiving chambers connected to one another via at least two two-dimensional, gas-conducting diffusion membranes including hollow fibers spaced apart from one another and at least partially fixed to one another; a gas supply receptacle on at least one gas receiving chamber; a shaft receptacle on at least one gas receiving chamber;
wherein the gassing unit for gassing the liquid in the reactor is supplied with process gas via the gas supply receptacle, is set into a rotational movement via the receptacle for the shaft and forms a convection flow within the reactor via rotational movement of the gassing unit in the liquid. Further included is a method for gassing a process liquid, a gas-liquid reactor including a gassing unit, and the use of a gassing unit for supplying biological cultures with process gases.

Ingredient blending devices and associated methods are disclosed herein. In some embodiments, an ingredient blending device includes a cup holder assembly, a straw displacement assembly, a gas pumping assembly, and a controller. The controller can be configured to (i) operate the straw displacement assembly to position a straw such that a proximal end of the straw is adjacent the gas pumping assembly and a distal end of the straw is at least partially inside a cup, (ii) operate the cup holder assembly to move the cup relative to the straw, (iii) operate the gas pumping assembly to pump the gas into the proximal end of the straw such that the gas exits at the distal end of the straw and into ingredients in the cup, thereby blending the ingredients, and (iv) operate the straw displacement assembly to dispense the straw into the cup.

A wastewater purification apparatus includes an elongate tank, which has an inflow for feeding wastewater, a first vertical agitator with a first hyperboloid agitator body mounted on a vertical first agitator shaft and provided in a first treatment portion downstream of the inflow on the first narrow side, a second vertical agitator with a second hyperboloid agitator body mounted on a vertical second agitator shaft and provided in a second treatment portion downstream of the first vertical agitator, an aeration device with a fan for aerating wastewater received in the tank, a first drive device for rotating the first hyperboloid agitator body in a first rotation direction, a second drive device for rotating the second hyperboloid agitator body in a second rotation direction opposite the first rotation direction, and a decanter for discharging purified wastewater in a third treatment portion on a second narrow side opposite the first narrow side.