Aug 72 min read

Proper Water Treatment for Cooling Towers: A Four-Legged Stool Approach - Leg 3, Microbiological Control

In today's post, we explore Leg 3: Microbiological Control as part of our series on cooling tower maintenance.

Leg 3 - Microbiological Control

Cooling towers provide an ideal environment for the growth of algae, bacteria, and other microorganisms. These can form biofilms on heat exchange surfaces, reducing efficiency and potentially leading to health hazards, such as Legionnaires' disease. Effective microbiological control is essential to maintaining a clean and efficient cooling tower.

Biocides: The primary method for controlling microbiological growth is the use of biocides. There are two main types of biocides used in cooling towers:

Oxidizing Biocides: Include chlorine and bromine, which destroy microorganisms by oxidizing their cell walls. Oxidizing biocides are highly effective but can be corrosive to cooling tower materials if not adequately controlled.
Non-Oxidizing Biocides: Include chemicals like glutaraldehyde and isothiazolinones, which kill microorganisms through different mechanisms, such as disrupting cell membranes. Non-oxidizing biocides are typically used in combination with oxidizing biocides for comprehensive control.

Biofilm Control: In addition to biocides, biofilm dispersants can be used to break up existing biofilms and prevent their formation. These chemicals penetrate biofilms and loosen their attachment to surfaces, making them easier to remove.

Monitoring and Testing: Regular microbiological testing is essential to ensure effective control. Dip slides and ATP (adenosine triphosphate) tests can be used to measure the concentration of microorganisms in the water. These tests provide a quick and easy way to monitor microbiological activity and adjust treatment protocols as needed.