Case Study from HydroFLOW Italia
Legionella control without chemicals in an ageing hotel system
Legionella control without chemicals was the only option at Hotel Des Etrangers in Milan. Legionella kept returning to the hotel’s domestic hot water system, but the installation was old enough that chlorine dosing risked corroding the pipework it was meant to protect. Biofilm inside the pipes gave the bacteria somewhere to shelter, and scale was affecting system performance. In December 2017 one HydroFLOW® C100 was installed on the cold supply and one HydroFLOW® P100 on the hot water delivery. During an initial cleaning phase, deposits detached from the pipe walls and were seen at the outlets. Since then Legionella has not reappeared, biofilm has been removed from pipe surfaces and no new scale has formed.
The Challenge
- Legionella control without chemicals was needed because the ageing system could not take chlorine
- Legionella was recurring in the domestic hot water system
- Chemical dosing risked corroding the old pipework
- Biofilm had formed inside the pipes
- Scale deposits were affecting system performance
The Solution
- Units installed: one HydroFLOW® C100 and one HydroFLOW® P100
- Installation point: C100 on the cold supply, P100 on the hot water delivery
- Installed: December 2017
The C100 went on the cold supply and the P100 on the hot water delivery, treating the system from both ends. Because nothing is added to the water, this route to Legionella control without chemicals carried no corrosion risk to the ageing installation. The signal disrupts the conditions biofilm needs to hold on to pipe surfaces, so accumulated deposits detached and were flushed out at the outlets.
