Why Do I Need Biocide In My Cooling Tower?
Cooling water provides an ideal environment for biological growth, including Legionella. Because Legionella bacteria can be a health hazard, treating your cooling water properly with the most effective biocide (bacterial disinfectant) is an extremely important task.
What Types of Biocide Work Best?
There are two main classes of biocide:
- Oxidizing
- Non-oxidizing.
The difference is found in how the chemical attacks and kills bacteria.
Oxidizing Biocide
Oxidizing biocide kill bacteria through the electrochemical process of oxidation, where the biocide gains an electron from the bacteria, and this electron loss essentially kills the bacteria. Oxidizing biocides are typically made up of chlorine or bromine, and these halogens are the oxidizing agents disrupting the biological cell. Oxidizers are generally most effective in systems that have high water usage.
Non-oxidizing Biocide
There is a wide-variety of chemistry related to non-oxidizing biocide. Non-oxidizers are typically used on a prescriptive basis and introduced when there are special challenges with the water relative to the particular biological growth, the quality of the water, the pH, discharge limits/toxicity, metallurgy and chemical safety. This biocide class includes: DBNPA, Isothiazoline, Glutaraldehyde and Quaternary Ammonium.
How Can I Make Sure My Biocide Is Working?
Biocides are obviously only effective if they come in contact with the bacteria within the system. Ensuring proper contact time and adequate dosage in the system is vital to keep bacteria under control in your tower.
Oxidizing biocides typically take a couple of hours of contact time at a specific dosage, while non-oxidizing biocides should remain in the system much longer. Other factors that inhibit biocide effectiveness include dead legs (areas of stagnation) in the piping, off-line pumps and filters and areas of low flow.
Deciding what biocide to use in your system is only part of what it takes to maintain a clean system. There are also a multitude of control measures that should be clearly outlined, communicated and validated in a well-constructed Water Management Plan (WMP).
Chardon can help with bacteria control. Call us today for our cooling tower water treatment services!
