Legionella is a type of bacteria that can be found naturally in water sources such as rivers and lakes. However, it can become a health concern when it grows and multiplies in human-made water systems like cooling towers, hot tubs, and plumbing systems. When people come into contact with contaminated water droplets that contain Legionella, they may develop a severe form of pneumonia known as Legionnaires’ disease.
One of the most effective ways to control Legionella growth and reduce the risk of Legionnaires’ disease is by maintaining water temperatures that are known to kill the bacteria. In this article, we will discuss the science behind Legionella control and the temperature to kill legionella.
Legionella bacteria thrive in temperatures ranging from 77°F to 108°F, with an ideal growth range between 95°F and 115°F. These temperatures are commonly found in water systems that are not properly maintained or where hot water is stored and circulated. Legionella can also survive and multiply in biofilms that form on the inner surfaces of pipes and tanks, making it even harder to eradicate.
To effectively control Legionella growth, water systems should be kept either below 77°F or above 140°F. At temperatures below 77°F, Legionella growth is significantly slowed down, and the bacteria are less likely to multiply and cause infections. However, this method is not foolproof, as Legionella can still survive and become dormant in cold water, reactivating when the temperature rises again.
On the other hand, exposing Legionella to temperatures above 140°F is known to kill the bacteria within a matter of minutes. This process, known as thermal eradication, is one of the most reliable and effective methods for controlling Legionella in water systems. By raising the water temperature to a level that is lethal to Legionella, the bacteria are effectively eradicated, and the risk of Legionnaires’ disease is greatly reduced.
It’s important to note that thermal eradication should be done carefully and in accordance with industry guidelines to prevent scalding and damage to the water system. Additionally, it is recommended to have a Legionella risk assessment conducted by a qualified professional to determine the best course of action for Legionella control in a specific water system.
In addition to thermal eradication, other methods for controlling Legionella growth include regular cleaning and disinfection of water systems, flushing out stagnant water, and using biocides to kill bacteria. These methods can be used in conjunction with temperature control to create a comprehensive Legionella control plan that reduces the risk of Legionnaires’ disease.
In conclusion, maintaining water temperatures outside of the Legionella growth range is crucial for controlling the bacteria and preventing the spread of Legionnaires’ disease. By understanding the science behind Legionella control and the temperature to kill legionella, water system operators can take the necessary steps to protect public health and ensure the safety of their facilities. Thermal eradication is a proven method for killing Legionella, but it should be done carefully and in accordance with industry guidelines to achieve maximum effectiveness. Overall, a multi-faceted approach to Legionella control that includes temperature control, cleaning, disinfection, and risk assessments is the best way to ensure a safe and healthy water system.