Part 3 - Legionella Basics and Prevention Programs

In the third installment of the 4 part series covering Legionella basics and prevention, we will briefly review cooling tower water treatment methods designed to control Legionella.  This is done by changing the conditions that are favorable for the bacterium’s growth. 

For cooling towers, the following methods are recommended for Legionella prevention:

•  Water treatment programs preventing:
  • Corrosion
  • Scale
• Biocide programs preventing microbiological growth.
• Implementing anti-foulant programs
• Conducting yearly wash out and cleaning programs

To determine the best preventative treatment or disinfectant, an initial sampling of various areas within the cooling tower can provide an indication of Legionella. If remedial control measures are required, treatment plans should be consistent with  OSHA’s recommendations. These methods include cleaning, along with the addition of chlorine and dispersants.  A thorough review of the water treatment program should also be conducted. In closed water systems (Domestic Hot Water) a different approach is required. These methods include using chlorine dioxide, sodium hypochlorite, monochloramine, and copper-silver units. Earthwise Environmental can recommend the best treatment program for your system.