Legionella & Biofilm Control

Legionella and biofilm can create serious water system risks in facilities that rely on recirculating water, including cooling towers, hot water systems, pools, fountains, and other institutional or commercial systems. Chlorine dioxide is used to help control biofilm and Legionella in these environments, offering fast and effective disinfection at very low doses.

Why Legionella Is a Water System Concern

Legionnaires’ disease, also known as Legionellosis, is caused by Legionella bacteria. Legionella can often proliferate within biofilm on the inner surfaces of water systems, where bacteria and other organisms are protected from many biocides. Legionella can grow in water temperatures up to 140°F or more, making it especially problematic in warm, recirculating water systems.

These risks are especially relevant for:

• Cooling towers
• Ornamental fountains
• Hot water systems
• Hospitals
• Hotels
• Nursing homes
• Prisons and other institutional facilities

How Biofilm Supports Legionella Growth

Biofilm is a layer of bacteria, protozoa, algae, and other organisms held together by a polysaccharide matrix produced by bacteria. This protective layer can make organisms harder to control with many common biocides.

As biofilm grows thicker, pieces can break away and move through the water system. Legionella may also infect protozoa within the biofilm. When those protozoa are released into the water stream and die, they can release Legionella into the system. Biofilm can also reduce system performance by restricting water flow in pipes and tubing and inhibiting heat transfer in heat exchangers.

How People Are Exposed to Legionella

People usually contract Legionellosis by breathing in contaminated aerosols. These aerosols may come from showers, bathroom fixtures, cooling towers, fountains, or other water systems that can create airborne mist or droplets.

Chlorine Dioxide for Legionella and Biofilm Control

Chlorine dioxide is used to control biofilm and Legionella across a range of water systems. It is a fast and effective disinfectant at very low doses, does not require rinsing, and leaves no taste or odor.

Common applications

Chlorine dioxide is used for biofilm and Legionella control in the following:

• Cooling water systems and cooling towers
• Recirculating hot water systems in hospitals, hotels, nursing homes, prisons, and other institutions
• Swimming pools, hot tubs, Jacuzzis, and similar systems
• Fountains and decorative pools
• Evaporative coolers
• Tank cars and trucks

To learn more about chlorine dioxide use for Legionella and biofilm control, contact CDG today.