Legionella is a bacterium that can occur in water and can be easily controlled by USAF™ (ultrasound). Inhaling the legionella bacteria in the form of water vapor can have fatal consequences for human health. Especially so-called wet cooling towers can be a problem because of atomization of the water in the open air.


USAF™ is very effective in combination with the legally prescribed chemical agents that must be present in the water. This is because one technique complements the other.

Ultrasound can effectively damage bacteria, as concluded in a literature study carried out by the University of Utrecht, entitled “Ultrasound as a sterilization method”.

Ultrasound as a sterilization method

Conclusion on page 26: “Bacteria are generally killed very effectively by sonication and cavitation”. This literature study also states on page 29 that a combination with another technique is “very effective”.


General operation of the USAF ™ units is explained in the General section of this website.


Bacteria will tear the membranes of bacteria under the influence of the pressure waves, making the DNA directly accessible to the chemical agents present.

The treatment is much faster than with chemical means alone and much more effective and faster. This is because the tearing of the membranes takes place immediately. Chemicals normally take some time to dissolve the membranes.

In addition to the literature study in Utrecht, tests in horticulture with the fusarium fungus have also shown these effects. The use of the amount of chemical agents was reduced substantially (-75%).

Each tank in the cooling system can be equipped with an USAF ™ unit. Every time the water with bacteria passes the ultrasonic unit, the bacteria are damaged and the chemistry present will immediately destroy the DNA.


The advantage of placing the USAF™ units in the tanks is that the USAF™ also combat the biofilm. Bacteria need biofilm to multiply, this is prevented.

This directly and indirectly fights the legionella bacteria. 

For more information see “biofilm” in General.

Benefits USAF ™

Prevents outbreaks

Improved chemical action

USAF ™ is a catalyst

Reduces use of chemicals

Combats biofilm

In accordance with regulations

Environmentally friendly