Cooling Towers & Legionnaires Disease

The largest outbreak of Legionnaires’ disease in New York City history was traced to a cooling tower at a Bronx hotel in 2015. Over 120 people were infected and 12 of them died causing health officials to establish regulations for ongoing Legionella control measures. In March of 2016 in Sydney, Australia, 12 cooling towers tested positive for Legionella levels above the regulatory threshold. The most recent outbreak occurred in November of 2016 in Lake County, Ohio where investigators believed the Legionella bacteria was likely spouted into the air from cooling towers at an industrial plant. Cases of Legionnaires’ Disease are continuing to grow every year.

Cooling towers are an energy, space and cost-effective way to remove heat generated by centralized air conditioning systems from large buildings or industrial processes.  The towers do this by using water and an evaporation process to pull the heat away and transfer it outside, thus creating a comfortable indoor environment.  Because cooling towers contain large amounts of water, they become potential breeding grounds for Legionella bacteria if they are not properly disinfected and maintained. Water within cooling towers is generally warm, which is an ideal environment for Legionella heat-loving bacteria to grow. Also, most cooling towers have surfaces that are not constructed of anti-microbial materials allowing bacteria to grow such as Legionella.

An unwanted byproduct of this process is the collection of dust and debris that settles in the basin of the cooling tower. Problems occur if the cooling tower is left unmaintained which will lead bacteria to flourish in this particle concoction due to the presence of ideal growing conditions. There are many factors favoring the occurrence of Legionella in your cooling towers such as warm stagnate water at temperatures between 90°-105°F, presence of ferrous ions caused by biocide treatments, sediment, sludge, scale, and organic materials or biofilm.

Per the Centers for Disease Control and Prevention, Legionnaires’ disease is a serious type of pneumonia caused by bacteria, that live-in water. Legionella can make people sick when they inhale contaminated water from building water systems that are not adequately maintained. Unfortunately, Legionnaires’ disease is on the rise in the United States. It may not always be severe; in community outbreaks, mild cases may be recognized that would probably have escaped detection except for the increased awareness of the disease.

If the proper steps for taking care of a cooling tower aren’t followed, then Legionella growth is possible. In order to control Legionella bacterial growth and consequently prevent disease outbreaks, there are four key steps to take for establishing a clean cooling tower that performs to expectations. These steps consist of:

  • Regular maintenance
  • Systematic filtration
  • Water treatment
  • Continuous monitoring

There are many innovative technologies on the market today that can help prevent the growth of Legionella in cooling towers. One of the most effective include an anti-microbial cooling tower from Delta Cooling Towers. Delta’s cooling tower has the only anti-microbial efficacy against Legionella bacteria out of all the common cooling tower materials. The anti-microbial resin is compounded into the plastic material so it will not fade or wash away.

To get a quote for our any of our cooling tower products, visit the quote form.

For more information, contact Delta Cooling Towers, Inc. at 800.289.3358

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