Water is essential for life, but in water systems it can become a breeding ground for microorganisms. Bacteria multiply especially quickly when water stands for a long time, the temperature is warm and the environment is oxygen-rich.
Microorganisms, including pathogenic forms, begin to grow intensively when water stands for a long time, in a warm room and in an aerobic environment. For example, in open cooling systems direct sunlight is also suitable for the growth of microorganisms.
Because such conditions can give rise to microorganisms that are dangerous to health, including disease-causing ones, it is important to inspect water systems regularly and disinfect them when necessary.
Under the applicable requirements, the microbiological parameters of drinking water must be under control.
For example:
- Escherichia coli – 0 / 100 ml
- Intestinal enterococci – 0 / 100 ml
- Clostridium perfringens – 0 / 100 ml
If the values of these quality parameters are elevated, there is a risk that the water is microbiologically contaminated.
It is also important to monitor the level of Legionella bacteria, which must remain below 1000 CFU/l. Legionella spreads through water aerosols, and the main risk points are showers, taps and cooling systems.
Biofilm – a hidden problem
Biofilm (so-called “slime”) often forms on the inner surfaces of pipework and tanks.
Biofilm:
- creates an ideal environment for bacterial growth
- protects microorganisms from disinfection
- reduces the efficiency of systems
Even a biofilm less than 1 mm thick can reduce heat transfer by up to 50%.
Solution
Two main methods are used to disinfect water systems:
✔ Continuous disinfection: a chemical is dosed into the system continuously to keep the level of microorganisms under control.
✔ Shock disinfection: a chemical is introduced into the system either once or regularly at set intervals.
These methods are often used in combination (e.g. in cooling systems).
In addition to chemical methods, microorganisms can also be kept under control with UV disinfection.
Good to know
When disinfecting, the following must be considered:
- which microorganism is present in the system
- how extensive the problem is
- whether the water comes into contact with people
When choosing a disinfectant chemical, its possible contact with people is decisive. Some chemicals are strong oxidizers and are not suitable for use in the concentration required for disinfecting drinking water. In that case, water use must be stopped for the duration of the work and alternative drinking water provided.
When needed, Miridon carries out the work at weekends or in the evenings, when the building (or part of it) that needs disinfection is empty and no water is being used.
