While many facilities are focusing on precautions for preventing the spread of COVID-19, they also need to be proactive when it comes to reducing the risk of Legionella. 

It is not up for debate: You should follow a cooling tower maintenance program to thwart the development of Legionella. And to prevent the outbreak of Legionnaires’ disease within cooling towers, you should follow a few tips for cooling tower maintenance.

Cooling corrosion-control programs have traditionally utilized phosphate, metals or film-forming chemistry. As cooling water cycles in concentration, the aqueous environment becomes more corrosive due to elevated conductivity, chlorides and sulfates.

Facility managers are responsible for keeping their plants and buildings as safe as possible. This includes mitigating and preventing the contamination of cooling towers from dirt, bacteria and other dangers. COVID-19’s impact on sources such as cooling towers and HVAC systems is still being researched. However, cooling towers are a common source for the growth of infectious bacteria such as Legionella.

BioSpray Tower will disinfect hard, nonporous surfaces, says the manufacturer. The EPA-registered disinfectant kills 99.9 percent of Legionella pneumophila when correctly applied to hard, nonporous surfaces like cooling towers.

Facility managers are often faced with a decision whether to test utility and potable water for Legionella bacteria. Moreover, there are two different event types that most owners will face regarding Legionella: surveillance and clinical. In a blog post, U.S. Water explores when and how many locations to test.

The only way to determine if your cooling tower system is clean is Legionella testing. It gives operators and operators an opportunity to find out if their system contains high levels of Legionella. If elevated levels of bacteria are measured, owners and operators should take corrective measures to clean and disinfect the tower. 

Winter layup of cooling towers can create an environment susceptible to growth and incubation of corrosion-causing bacteria. Cooling tower cleaning and maintenance prior to spring startup is recommended by OSHA to remove biofilm and prevent Legionella bacteria. 

A third-party study by Special Pathogens Laboratory, a CDC-ELITE facility, demonstrated that reactive oxygen species (ROS) ions were effective at achieving a 6-log reduction of Legionella Pneumophila in less than 10 seconds after reaching an ORP +650 mv.

During process cooling, the cooling water absorbs large volumes of airborne particulate while the cooling tower acts as an air scrubber, filtering the surrounding air. With time, these fine particles can build up and settle within the system, adversely affecting cooling performance while lowering the life of wetted subcomponents.