Legionella control Aquados®


VLM B.V. carries out disinfection of drinking water lines at completion/start-up  of new drinking water systems, or when a microbial infection in an existing system has been detected. Examples of sectors that may benefit from disinfection of (drinking) water line  systems are:  healthcare, sports, recreation, hotels, camping, industry, etc.

After composing a risk assessment and control plan, the water line system has to meet the set criteria. Next to this, it is recommended to periodically treat the water lines pre-emptive with a disinfectant, to prevent or remove a potential biofilm. A biofilm is a slimy coating on the inside of water lines which can act as a breeding ground for bacteria.

VLM B.V. developed a procedure that enables to clean water lines thoroughly, quickly and efficiently in a safe way. VLM B.V. can also give advice regarding a continuous disinfection system to prevent potential microbial infections of water line systems.

Disinfection procedure

Temporary installation of the Aquados® disinfection box directly after the water meter enables to treat both the cold- and warm water circuit. During the disinfection procedure, the supply water is diverted through the disinfection box, which adds the required amount of disinfectant to the water (by means of a water meter and a metering pump).  By opening faucets and other tapping points at the end of the water lines, the system is automatically filled with water containing the right (low) dose of disinfectant.

After the disinfectant has been detected at all tapping points (by means of test strips), all tapping points will be closed again and a certain contact time will be applied. After this contact time, the system is rinsed with clean water (again checked with test strips) and the Aquados® disinfection box will be removed. When the disinfection procedure is completed, one or multiple water samples can be taken (in consultation with the client) for analysis by an external accredited laboratory on the presence of legionella. After approximately 10 days, the results of the analysis will be available.

Key considerations for legionella prevention

  • Avoid dead ends and areas with very little flow as much as possible when constructing water line systems.

  • Ensure a temperature of at least 60 °C at the tapping points.
  • Be aware that legionella can also cause problems in cold water circuits; especially in water lines below basins or flat roofs, water lines in outer walls and water lines close to the hot water circuit.
  • Ensure proper maintenance of the water supply system, e.g. descaling of showerheads and prevention of biofilm formation.

Results legionella disinfection Aquados®