Often fine bubble diffusers are installed in the same tank with flow boosters. This is the case for the Oxidation Ditch process, for example. Care must be taken to place the diffusers far enough from the boosters and calculations of oxygen transfer efficiency should consider the effects of the boosters.

Diffusers should be place no closer than 20 ft (6m) from the discharge of a flow booster. On the suction side, the booster should be protected from cavitation, hence it is recommended to follow booster manufacturers' recommendations to ensure that they are protected.

The effect that boosters have on fine bubble diffuser efficiency depends on the density of the diffusers. Generally, the less dense the diffuser array, the less impact the flow boosters will have on SOTE (standard oxygen transfer efficiency).

When membrane diffusers are placed densely in a grid the air bubbles produce a "wall" of air. This can sometimes cause short circuiting of the water which is trying to flow through it.

On the other hand, in sparsely arranged grids, the presence of horizontal channel velocity from the boosters tends to mitigate the tendency for bubbles to spiral as they rise (which often happens when diffusers are placed far apart in the absence of flow boosters).

In general, boosters are a negative for SOTE (standard oxygen transfer efficiency), but the extent to which they negatively affect SOTE depends on the layout. Pay close attention to your 3D CAD designs before applying your build. Designers should take care to spread diffusers out in the basin insofar as possible to avoid short circuiting.

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