Air contact systems (aeration systems) are primarily used for mixing air with the water, this aids the oxidisation of certain components in the water. One of the most common uses is to oxidise soluble Iron and Manganese into insoluble hydroxides.

The air is drawn in using a Mazzei injector, this creates a venturi effect that draws air into the inlet pipe to the contact vessel. There is also a spring loaded bypass fitted, this will open automatically when a large volume of water is required to backwash a system following the aeration.

The feed pressure and flow needs to be sufficient to create the venturi effect, the system will also need to be placed before any accumulator on a pressurised system; all other filtration should follow an accumulator.

It is important to avoid back pressure on the Mazzei also any filtration following the aeration should not be higher; flow controllers should only be used on the final filter.

Usual and most popular sizes are
10 x 54 for Small Domestic Properties
13 x 54 for Large Domestic and light commercial