Legionellosis is the term used for infections cause by the inhalation of aerosolized droplets of water containing the Legionella Pneumophila bacteria. Legionellosis disease is a severe form of pneumonia that can result in severe complication, even death. With heightened concerns over legionella and the potential concern for Legionnaires disease, cooling tower operators are turning to IWT for solutions in managing the risk posed by Legionella bacteria. Control of the Legionella bacteria is straight forward, requiring good processes, technically sound programs, consistency in their application, monitoring and documentation.

No program can guarantee a cooling water system free of Legionella bacteria all the time. However, when a properly designed maintenance program and plan is followed:

  • Risk is limited
  • Factors influencing growth is reduced
  • Transmission is limited
  • Exposure is minimized

Maintenance Program and Plan Components

  1. System Assessment- A comprehensive mechanical and operational measurement of a cooling towers potential for the amplification and spread of the disease
  2. Effective Microbiological Control- Implementation of oxidizing and non-oxidizing biocides in combination with biofilm dispersants
  3. Physical Cleaning- Semi-annual cleaning of the cooling towers for removal of dirt, scale and biofilm
  4. Disinfection- Following a physical cleaning a hyper halogenation of the system should be accomplished as described in The Cooling Technology Institutes Standard WTB-148
  5. Monitoring- Validates the effectiveness of the MPP
  6. Documentation- Provides a record, that the selection and implementation of precautionary measures and treatments is minimizing risk of growth and exposure