Water System Legionella Prevention keeping you up at night? Delta’s Anti-Microbial Cooling Tower Shell is designed to resist Legionella growth in water systems. According to Delta, test results from Special Pathogens Laboratory, The Legionella Experts, prove that Delta tower displays the only Anti-Microbial efficacy against Legionella bacteria out of all the common cooling tower materials. The bacteria tested were Legionella Pneumophila Serogroup 1. The base materials tested were Delta Compounded HDPE, FRP, and Stainless Steel and the numbers reflect bacterial count after 24 hour incubation.
Compared Delta’s results to others:
| Cooling Tower Shell | Anti-Microbial Efficacy |
| Delta AM HDPE | Yes |
| Stainless Steel | No |
| FRP | No |
| Anti-Microbial Fill | Yes |
| Standard Fill | No |
How do Delta Cooling Towers protect against Legionella?
The Tower Shell with Anti-Microbial HDPE resin is compounded throughout, resists bio-film growth and withstands most aggressive chemical treatments.
The Delta Tower Fill & Drift Eliminator
- Features Anti-Microbial Compounded PVC or PP
- Impedes Microorganism Growth
- Prevents Fouling Maximizing Performance
- Resists Bio-film Growth
Stagnant Water is a breeding ground for microorganisms which reproduces Legionella. Our design prevents stagnant water.
- Aggressive Slope Side to Side
- 3% Slope Back to Outlet
- Basin Sweeper System on Some Models
Download Delta Cooling Anti-Microbial-Brochure
Download frequently-asked-questions
Contact a Kerr Sales Engineer for further information and quotes using the form on the right.
About Legionella bacteria
According to Delta Cooling,
Legionella bacteria can cause harmful lung infections. This bacteria grows best in warm water conditions where it is spread to humans when water vapor or mist containing the bacteria is inhaled. Cooling towers have an ideal environment for this growth. Although the public concern about Legionnaire’s Disease was paramount during the outbreaks of the mid-1970s, there have been many recent occurrences since then, including over a dozen cases in the U.S., as well as several in Europe and Australia. According to the CDC, in many of these cases Legionella is incubated and spread through water systems, including the cooling towers that are essential items in commercial building HVAC systems and industrial process cooling.
What promotes growth?
- Poor water flow and areas where water is stagnant, common to cooling tower designs with a large flat bottom basin, which will have stagnant water in the corners.
- pH between 5.0 and 8.5, water temperatures between 68°F and 122°
- Sediment that promote growth of commensal microflora
- Microorganisms including algae, flavobacteria, and Pseudomonas, which supply essential nutrients for Legionella growth or harbor the organism
What prevents growth?
- Chemical Water Treatment: Oxidizing Biocides are recommended as the best mode of control. Warning: this type of biocide can be aggressive towards metal surfaces; specifically, metal cooling towers.
- System Design & Engineering: No stagnant water, sloped basin, and/or basin sweeper system.
- Maintenance – Competent consistent water treatment and monitoring most important.
- According to the Center for Disease Control and Prevention, about 5,000 cases of Legionnaire’s disease are now reported each year in the United States.
