How to Control Chloramines?
How to control Chloramines in pools & spas?
In this post How Safe Is Swimming Pool Water? we saw that, the chlorine in pool water reacts with the contaminants in water to form complex chemicals called as Chloramines or combined chlorine.
Chloramines are the primary culprit for the “pool smell”. Though this is not a very scientific method, you can often tell if a pool might have a Chloramines issue, just by the Chlorine smell of the pool.
Chloramines in pool water also cause eye & skin irritation and breathing difficulties for people with Asthma. Young kids and the elderly are especially susceptible to adverse health effects of Chloramines.
Health risks of Chloramines are well known. As a result, most public pools, swim schools and spas in Australia are legally required to control Chloramines below 1mg/L.
The Chloramines risks are more acute in indoor swimming pools or covered pools.
So what is the best way to destroy Chloramines?
1. Chemical methods like continuous break-point chlorination, shock chlorination and shock dosing with Hydrogen Peroxide are one way to try and control Chloramines. Like any chemical method, these simply add more chemicals to the pool water. In addition, the success of these methods depends on many factors like bather load, temperature and other factors that are difficult to control.
If something goes wrong with one of the chemical methods, it is easy to increase the level of Chloramines in your pool! As a result this is not a particularly reliable way to control combined chlorine in pools.
2. Ozone in pool water injection is another way to control Chloramines. Ozone is a very strong oxidant and has the additional benefit of disinfection. However, ozonated water may need to pass through granular activated carbon filters to remove excess Ozone. Ozone generators can also be expensive over the long term.
3. UV light to control Chloramines is a very reliable and economical method. Medium pressure UV lamps emit polychromatic UV radiation. The multiple wavelengths in medium pressure UV lamp radiation destroy the molecular bonds of combined chlorine/Chloramine compounds.
Therefore, UV removal of Chloramines is a non-chemical and reliable method to control combined chlorine in public pools. It is also possible to control combined chlorine with adequately sized low pressure UV unit.
4. Advanced Oxidation by combining UV and Ozone is a relatively new approach to Chloramine control in pools. UV radiation, when combined with Ozonated water in the correct way, generates OH radicals. OH radicals, also known as hydroxyl radicals, have very high oxidizing power. These OH radicals and the UV radiation break down molecular bonds of combined chlorine in a reliable way.
5. Fresh water dilution – if all else fails, is the last option. Draining precious water is not really a solution, is it?
This NSW Department of Health page covers Chloramine control in pools in more depth.
If you have any questions about controlling combined chlorine in your pool, please feel free to call (02) 9896 1165 or contact us for more information or assistance.