Aeration means introducing gases into a liquid. It serves two purposes: replacing a gas that is present or dissolved with another one, or supplying gas so that aerobic fermentation or gas-liquid reactions can take place. A large interface between liquid and gas is crucial.
Side effects of aeration
Introduced gas can form foam, separate mixtures and create shear forces through rising air bubbles. As a result, the product can separate or important ingredients can be destroyed. Therefore, the geometry of the agitator is especially important, and agitation must be planned as part of the process.
Decoupling gas supply and mixing
Porous feed nozzles create the small gas bubbles. The agitator then only mixes the liquid.
One fast agitator
For simple processes, a fast-running agitator can do both.
The gas flow should break up into as many small bubbles as possible. In fermentation, however, the shear energy must not destroy the cell cultures.
Applications
- Biotechnology: in the fermentation of aerobic cell cultures, oxygen content, pH, temperature, density and system pressure must be monitored
- Foam must be avoided, because it clogs the exhaust air filters and product can escape
- Nevertheless, the agitator must distribute nutrients and cultures evenly
- Wastewater treatment: here the process is easier to handle and is used on a large scale, combined with physical, biological and chemical steps
The counterpart is deaeration. We are happy to advise you on both processes.
Other processes
Frequently Asked Questions about aeration
What is aeration (gassing)?
The introduction of gases into a liquid – for example to replace a dissolved gas with another or to enable aerobic fermentations and gas-liquid reactions.
What is important for effective aeration?
The largest possible phase interface between gas and liquid, i.e. many small gas bubbles – without the shear energy damaging sensitive cell cultures.
Which side effects can aeration have?
Foam formation, separation and shear forces from rising bubbles, which can separate the product or damage ingredients. That is why agitator geometry is particularly important.
Where is aeration used?
Mainly in biotechnology for the fermentation of aerobic cell cultures and on an industrial scale in waste water treatment.