Comprex® Magazine
Legionella control: Effective measures to ensure drinking water hygiene
Legionella control: Effective measures to ensure drinking water hygiene
Find out how legionella develops and how you can protect your drinking water system safely and without chemicals. Discover the most effective methods for legionella control!
Introduction
Legionella is an often underestimated risk to drinking water hygiene, especially in larger buildings and complex piping systems. These bacteria, which occur naturally in bodies of water, can multiply rapidly in inadequately maintained drinking water systems and pose serious health risks. Legionnaires’ disease, a severe form of pneumonia, and the milder Pontiac fever are among the greatest dangers.
For operators of drinking water systems in public and residential buildings, regular legionella control is therefore of central importance. Targeted preventive measures and suitable cleaning techniques, such as those offered by our Comprex® pulse flushing process, can effectively combat legionella and remove it from the system in the long term.
This article sheds light on the causes of legionella, shows common control and prevention methods and explains why regular maintenance and cleaning of the drinking water system is essential.
The most important facts in brief: Legionella bacteria are particularly dangerous in drinking water systems if they are inhaled, for example through showering. Regular cleaning and maintenance is the most effective protection. Legionella is most effectively combated by regular thermal disinfection and the avoidance of stagnant water. Mechanical cleaning processes such as our patented Comprex® process offer a sustainable and chemical-free solution for combating legionella
Legionella: Causes and risks
Legionella are bacteria that occur in low concentrations in nature, especially in fresh water. However, they are particularly dangerous when they multiply in drinking water systems, which happens under certain conditions. Legionella love
The health risks are considerable. If legionella enter the lungs via the finest water droplets, for example when showering, they can cause severe legionnaires’ disease, which is fatal in up to 15 % of cases. A milder, flu-like form of the infection is Pontiac fever. It is therefore crucial to prevent the proliferation of legionella bacteria by taking appropriate measures to ensure the safety of drinking water hygiene.
Thermal disinfection as the most effective measure
One of the most effective methods for combating legionella is thermal disinfection. This method is based on the fact that legionella die at temperatures from around 55°C and can be completely eliminated from 60°C. The higher the temperature, the faster and more effectively the bacteria are killed.
In practice, a so-called legionella circuit is used for thermal disinfection, in which the hot water system is regularly heated to temperatures above 60°C. It should be noted that different temperatures require different exposure times:
- 55°C: Killed within hours
- 60°C: Killed within minutes
- 70°C: Immediate killing of legionella
Regular heating of the hot water is crucial not only to kill legionella, but also to prevent it from multiplying in the long term. Especially in hot water systems of larger buildings, such as hospitals or residential complexes, this procedure should be carried out regularly. Our Comprex® process offers mechanical cleaning that effectively contributes to better temperature distribution throughout the system, further reducing the risk of legionella.
Interesting fact: In order to effectively kill legionella, not only should the hot water cylinder be heated, but all tapping points in the system should also be regularly checked and flushed. This ensures that the entire system remains safe and germ-free.
Chemical disinfection: advantages and disadvantages
In addition to thermal disinfection, there are also chemical methods to combat legionella. Chlorine, ozone or silver ions are often used to kill legionella. However, these methods have both advantages and disadvantages:
- Chlorine: Chlorine is often used in high doses to combat legionella. Although chlorine is an effective measure, in high concentrations it can lead to taste and odor problems in drinking water. In addition, high levels of chlorine are suspected of being harmful to health.
- Ozone: Ozone is a very effective disinfectant that reliably kills legionella. However, the disadvantage lies in the high costs and the technical effort required for ozone disinfection.
- Silver ions: Silver is often used as a supplement to other measures due to its disinfecting effect. However, the use of silver is strictly regulated and is subject to the recommendations of the Federal Environment Agency and the requirements of the Drinking Water Ordinance.
Overall, chemical disinfection methods are an effective short-term solution, but pose long-term risks, particularly due to possible residues in drinking water. We therefore recommend always reviewing the use of chemical agents and considering alternative, sustainable methods such as our mechanical Comprex® process.
Technical and structural measures to prevent legionella
In addition to disinfection, technical and structural measures also play an important role in the prevention of legionella. The correct planning and maintenance of water installations is crucial to prevent the proliferation of legionella.
- Avoidance of dead pipes: Pipes that are not used regularly provide ideal conditions for legionella to multiply. Therefore, such dead pipes should be avoided or shut down.
- Circulation pumps: To avoid stagnant water, circulation pumps should be used to keep the water constantly moving and thus maintain the temperature in the entire system at a safe level.
- Fresh water stations: In many cases, fresh water stations that treat the water as required are a better alternative to large storage systems in which water stands for longer and legionella can multiply.
Interesting fact: The installation of fresh water stations can significantly reduce the risk of legionella, as the water is only heated when required and there are no long standing times in the system. This solution is particularly recommended for larger buildings and systems.
Such measures can significantly reduce the risk of legionella proliferation. Our cleaning processes are designed to optimally support such technical solutions and ensure long-term drinking water hygiene.
Regular inspection and maintenance
The regular inspection and maintenance of drinking water systems is required by law and is essential to effectively combat legionella. The Drinking Water Ordinance stipulates that operators of larger water supply systems must have regular tests carried out for legionella.
Important test points are:
- Functionality of legionella filters
- Temperature monitoring in the hot water system
- Status of the circulation systems
If a positive legionella result is found during an inspection, measures must be taken immediately. These include thermal disinfection and comprehensive sanitation of the system. With our Comprex® process, we offer a quick and effective solution for thoroughly cleaning the affected pipes.
Prevention measures for private individuals
Private individuals can also contribute to the prevention of legionella. There is a particular risk of legionella in households with hot water storage tanks and irregular use.
The following measures are recommended:
- Regular use of all water outlets: Water should not stagnate. If pipes are not used for a long time, the risk of legionella increases.
- Legionella filters on shower heads and taps: These filters can prevent legionella from entering the respiratory tract.
Important! Thermal disinfection after long downtimes : After a vacation or a longer absence, the hot water should be heated to a temperature of over 60°C for a few minutes.
These simple measures can also significantly reduce the risk of legionella infection in the home.
Common mistakes in legionella control
In legionella control, typical errors occur time and again that impair the effectiveness of the measures. The most common errors include
- Incorrect temperature control in the hot water cylinder: The temperature is often set too low, which encourages the growth of legionella bacteria.
- Insufficient chemical disinfection: If chemical disinfectants are not used in the correct dosage, legionella can survive and continue to multiply.
- Underestimated risks from stagnant water and dead pipes: Stagnant water provides ideal conditions for legionella to multiply.
Frequently asked questions (FAQs) about legionella control
How often should thermal disinfection be carried out?
Thermal disinfection should be carried out regularly in hot water systems to prevent the accumulation and proliferation of legionella bacteria. We recommend carrying out this measure approximately every three to six months. In particularly high-risk systems, such as hospitals or retirement homes, the frequency of disinfection should be adapted to the specific requirements. Regularly heating the water to over 60°C ensures that legionella is killed and does not pose a health risk. Our mechanical Comprex® process helps to further increase the efficiency of such thermal processes.
Is chemical disinfection harmful to health?
Chemical disinfectants such as chlorine or ozone are proven methods for combating legionella. However, high concentrations or improper use can be harmful to health. Chlorine, for example, can lead to unpleasant changes in taste and odor in drinking water. If the dosage is too high, there is also a risk of harmful by-products such as trihalomethanes forming. It is therefore important to strictly adhere to the recommended dosage. In our experience, chemical disinfection should only be used when other methods are not sufficient. We prefer mechanical methods such as Comprex®, which do not require chemicals but are still very effective.
What temperature should ideally be maintained in the hot water system?
To combat legionella effectively, the temperature in the hot water storage tank should be kept at a minimum of 60°C. This temperature guarantees that legionella bacteria are killed and prevented from multiplying. In circulation systems, the return temperature should not fall below 55°C to ensure even heat distribution throughout the system. In large systems in particular, it is important that the temperature is continuously checked and adjusted if necessary. Our Comprex® cleaning technology can help here by removing deposits in the pipes and thus ensuring optimum heat transfer.
Can legionella infestation occur without visible signs?
Yes, a legionella infestation can often go unnoticed, as legionella is neither visible nor does it affect the taste or smell of drinking water. This means that an infestation can occur even without obvious signs such as turbidity or an unpleasant odor. The bacteria multiply unnoticed, particularly in stagnant water pipes or poorly maintained hot water systems. Regular testing, especially in public or commercial buildings, is therefore essential to ensure that the water is free of legionella. An important part of our services is the regular inspection and cleaning of piping systems in order to effectively combat invisible dangers such as legionella.
What happens if legionella is detected in a water sample?
If legionella is detected in a water sample, immediate measures must be taken to minimize the risk to users. The first steps usually include increasing the hot water temperature (thermal disinfection) and using filter systems at the affected tapping points. In addition, all affected pipes should be thoroughly cleaned to completely remove the legionella bacteria. In such cases, we recommend using our Comprex® process, which works without chemicals and mechanically removes all deposits that promote the growth of legionella. This ensures a sustainable solution for improving drinking water hygiene.
Conclusion and recommendations
Combating legionella requires a combination of thermal disinfection, technical measures and regular maintenance. Drinking water hygiene can only be guaranteed in the long term if these measures are implemented consistently.
We recommend checking your hot water system regularly and using our Comprex® cleaning service to remove legionella safely and sustainably. In this way, you can protect the health of your users and increase the efficiency of your systems.
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