Aeration

Aeration is the process where water is subjected to intimate air contacting for the purpose of removing contaminating gasses or to saturate it with dissolved oxygen.  Aeration is used to remove undesirable gasses such as carbon dioxide and hydrogen sulfide.  Alternatively, it can be used for the removable of iron and manganese if this is not being done later on in the process by other means, such as ion exchange.  During the latter case, the metals are oxidized to form insoluble hydroxides which will precipitate out and can be settled or filtered.

The simplest approach to aeration is to diffuse air bubbles through a water tank.  Because this method requires large volumes of air, diffusion is limited to smaller flows.  When the flow rates are larger, air is forces through a blower at the bottom a degasifier.  It flows against the current of falling water.  Water and precipitate falls to the bottom of the degasifier where it is filtered or settles out.  Tank and vessel aeration refers to the process of introducing air or another gas into a liquid contained within a tank or vessel.  This is typically done for various industrial and chemical processes, as well as in water treatment and environmental applications. 

Oxygenation is one of the primary reasons for tank and vessel aeration is to oxygenate the liquid.  In biological wastewater treatment, for example, aerating the water allows aerobic bacteria to break down organic matter effectively.  Similarly, in aquaculture, aeration provides oxygen to fish or other aquatic organisms.

Reasons for aeration

• Mixing  -  Aeration can be used to mix different components within the tank or vessel.  When air or gas is introduced, it creates turbulence, helping to blend liquids or suspend solids uniformly.
• Chemical Reactions  -  In some chemical processes, introducing air or a specific gas can initiate or facilitate chemical reactions.  The increased surface area provided by tiny air bubbles can enhance the reaction rate and efficiency.
• Stripping Gases  -  In certain situations, aeration is used to remove unwanted gases from a liquid.  For example, in water treatment, aeration can help strip out volatile organic compounds or harmful gases like hydrogen sulfide.
• Temperature Control  -  In some cases, aeration can help regulate the temperature of the liquid inside the tank or vessel.  Air or gas can be used to cool or heat the liquid as needed.

Methods of tank and vessel aeration can vary widely, depending on the application and the desired outcome.  Common aeration techniques include diffusers, spargers, and mechanical agitators.  The choice of method depends on factors such as the size of the tank or vessel, the characteristics of the liquid, and the specific objectives of the aeration process.  It's important to note that tank and vessel aeration can be a critical aspect of various industrial and environmental processes, contributing to water quality, product quality, and overall process efficiency.