Reduce Legionella Risk With Cooling Tower Maintenance

By Ray Field

Even thinking of about the possibility of a legionella outbreak can cause panic for facility managers, and the recent outbreak in New York City is a hard-hitting reminder of how threatening it can be for a facility and the people occupying it.

While there are several potential sources for legionella, one of the most likely candidates is an infected cooling tower. These towers are an ideal place for legionella to flourish due to accumulated algae, mold, or bacteria mixing with the tower’s warm water. This creates a perfect environment for bacterial growth.

Ongoing and regular maintenance and cleaning of the cooling tower is the most vital part of managing legionella outbreaks. The importance of regularly cleaning cooling towers cannot be stressed enough. A poorly maintained system increases the chances that dangerous bacteria will multiply.

Instead of waiting for legionella to affect a facility, proper steps should be taken to reduce the chances by implementing a tower cleaning program.

What should be included in the plan?

Inspect Towers Monthly. Sediment, scale, and and slime can lead to buildup and help legionella grow and thrive. Regular inspections will help determine when to schedule cleaning.

Clean Tower Basin Surfaces. If sediment is visible, the basin needs to be cleaned, and cooling tower vacuums make it easier to remove contaminants without shutting down or draining the system.

Treat Circulating Water. Use a biodegradable descaler/antiscalant and dose biocides at recommended levels. Using a descaler in conjunction with biocides enhances biological control. A descaler will help remove tough scale allowing biocides to tackle legionella in the tower more effectively.

Drain and Clean. Set aside time annually to drain the system and perform a thorough cleaning before turning it back on. If a system has been offline for any length of time, be sure to disinfect.

Clean the Fill. The tower fill provides the perfect environment for bacterial growth, especially legionella. A cooling tower fill cleaner will clean lime scale and debris, and inhibit growth of other bacteria when used in conjunction with appropriate biocides. Protocols for disinfection of Legionella are well-defined by the Occupational Safety and Health Administration, the Centers for Disease Control and Prevention, and the U.S. Environmental Protection Agency.

A successful plan also involves having the right equipment for the job. Cooling tower cleaners help to remove the scale buildup and eliminate opportunities for legionella to hide. Cooling tower vacuums allow operators to remove contaminants from the sides and floors of the cooling tower without needing to drain the system or shut it down, making it easier to clean more frequently. The advancements in the design and technology of maintenance equipment allows facility management departments to find the best solution to meet their needs.

Preventing the growth of legionella is enough reason to take care of cooling towers, but it can also help to save money in energy and equipment costs. A dirty cooling tower needs to work harder and impacts efficiency. It also can cause stress on the equipment, leading to breakdowns.

Let the outbreak in New York City be a reminder of the potential devastation that can come from lack of prevention. Take the steps to keep your facility clean and operational, and you’ll be able to rest easier.

ray_field_headshotField is the director of chemical solutions for Goodway Technologies, a provider of industrial maintenance solutions. His primary background is in chemical engineering, and he has more than 22 years of experience in developing and marketing chemicals solutions for HVAC water treatment and other markets. Field holds a degree in Chemical Engineering and is a certified Water Technologist.