Legionellosis is a term that is used collectively to depict diseases caused by Legionella bacteria such as the serious Legionnaires disease as well as milder conditions like Pontiac fever. Legionnaires disease is a possibly fatal form of pneumonia, and all are at risk to contract this infection.
The Legionella bacteria are common in natural water sources like reservoirs, rivers and lakes but usually in small numbers. They are also found in functional water systems like spa pools, cold and hot water systems, evaporative condensers etc. In favourable conditions, the bacteria may multiply in large numbers causing Legionnaires disease. As such, it is important to take preventive and curative measures to deal with these bacteria.
While many measures have been identified for purposes of Legionnaires disease disinfections, some work better in some scenarios than others. Following are the main methods to contain these bacteria:
One among the best ways to control the growth of Legionella bacteria is to control the water temperature. The bacteria typically thrive in temperatures ranging from 20- and 45-degrees C. Therefore, the temperature of the water must be kept below 20 degrees in cold water systems and above 45 degrees in hot water systems. When this method does not work, other methods of Legionnaires disease disinfections should be considered.
Using Chlorine dioxide is a highly reputed method of keeping bacteria levels under control. It is an oxidizing biocide which is typically generated in-situ and is useful for applications of potable water. Its efficacy is dependent on a complete review of the site to determine the quantum of Chlorine required and how often it is required. This is impacted by many factors, such as water temperature.
Silver and Copper Ionisation
Several tests have proven that silver and copper ions can destroy 99.9% of Legionella bacteria. For instance, NASA used these to disinfect water aboard the Apollo Space Shuttles in the 1960s. Also, this method has been used with much success in UK hospitals. It has proven to be a powerful pharmaceutical water treatment method.
By combining Chlorine with Ammonia, Chloramines are created. The kind of Chloramine depends on the quantum of Ammonia and Chlorine present. This compound has been found to reduce bacteria contamination in the water dramatically. It releases far fewer by-products compared to using Chlorine on its own.
Filters to contain Legionella are special filters which are used typically at points where water is utilized (showers/ taps) for washing or drinking. Such filters have been proven to stop several waterborne pathogens including mainly, Legionella. But the filters need frequent replacement as filter pores to tend to get blocked over time, and this is a downside.
Using UV light is a disinfection technique which has been used to lower multiplication of these bacteria, mainly in hospitals. But as per research, UV light treatment must be used as a focal mode of disinfection, combined with other regularly used methods for accomplishing best results.
Silver Hydrogen Peroxide (Stabilized)
This compound is a chemical disinfectant created by using Hydrogen Peroxide with the addition of trace amounts of Silver for improving its potency. This substance is effective against Legionella, biofilm, and other pathogens. Hence, it is used to disinfect engineered water systems such as water tanks, pipe works and other components. The product of Sliver Peroxide as pharmaceutical water treatment has proven to be a highly effective mode for controlling Legionella bacteria as well as other waterborne pathogens.
Though this is not an ultimate list, these modes for Legionella disinfection have proven to work to reduce the content of Legionella bacteria to safe levels in human-made water systems. Some work in some situations as opposed to others. Research is still ongoing to find what is best and easiest to use in the battle against Legionella.