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Legionella control methods


It is recommended that hot water should be stored at >60 °C and distributed so that, after one minute of running, a temperature of at least 50 °C is attainable at outlets. Cold Water storage and distribution should be at 20 °C or below. In the UAE keeping the cold water below 20 °C is impossible. It forces engineers, contractors and owners to look for the correct water treatment system.


Ionization is the term given to the electrolytic generation of copper and silver ions for use as water treatment. The results of recent research have shown that where copper and silver ion concentrations can be maintained at 200-400 ug/ltr and 20-40 ug/ltr respectively, the technique is effective against Legionella in both hot and cold water systems. The use of pure copper and pure silver electrodes is essential to be effective. Online monitoring is a must in order to proof correct functioning of the system.


Chlorination is the process of applying any of the chlorine containing compounds such as sodium hypochlorite (bleach solution) to the water to achieve necessary destruction of all bacteria. As specially in the larger and more complicated buildings, the use of Chlorination is found to be not effective. High concentrations will also give smell and taste problems.

Chlorine Dioxide

Chlorine Dioxide is an oxidizing biocide capable of reacting with a wide range of organic substances. There are commercial systems available that release chlorine dioxide from a stabilized precursor solution into water systems. The maximum value of Chlorine dioxide in water should not exceed 0.5 mg/I as Chlorine dioxide. Chlorine dioxide level of 0.5 mgll can, if properly managed, be effective against planktonic Legionella in both the smaller hot and cold water systems.

Ultraviolet light UV, and Ozone

The previous treatment systems are effective throughout the water system downstream to the point of application. UV & 0zone can be used to treat Water at or very close to the point of application.

By |2017-08-31T09:39:50+00:00augustus 31st, 2017|Categories: Legionella control|0 Comments