Pools must be continuously treated with chemicals in order to deactivate pathogenic microorganisms and to prevent the spread of waterborne illness. Chemicals, such as chlorine, react with organic and mineral compounds, resulting in harmful and smelly by-products, among which is nitrogen trichloride.
Ensuring good water chemistry is the key to maintaining a proper and safe swimming pool environment. Not only to maintain a good level of oxidizers, but also to correctly monitor pH, water hardness, alkalinity, etc.
When dealing with chloramines, there are only a few options. The available techniques today include adding fresh water, hyper-chlorinating, non chlorine shocking, ozone, or installing a nultraviolet sanitizing system.
But first, let’s make the point: prevention is key. Chloramines are produced when bathers introduce ammonia and organic compounds into a swimming pool. If bathers shower prior to swimming, this would substantially reduce chloramine creation but not eliminate the issue.
The second point is about the filter. A good filter is key to clean water. It is always possible to manipulate the filter such as adding granulated activated carbon which will help to remove chloramines or ammonia. So, filtering is critical in pool sanitation and may require additional attention.
Water addition. This results in millions of gallons of fresh water, which is obviously highly wasteful, but also presents a new problem of having to constantly monitor the pH, temperature adjustment and alkalinity of the water and disposing water with lots of chemicals into the sewer system.
Non-chlorine shock with mono per sulfate-based oxidizers. These products are very expensive compared to chlorine but are strong oxidizing agents to breakdown chloramines when reaching breakpoint oxidation. The use of non-chlorine shock will require more intense water chemistry monitoring.
Hyper chlorination to remove chloramines. As a part of regular maintenance, you shock a pool periodically to remove organic compounds, remove chloramines and free up the available chlorine to allow it to sanitize the pool. However, this also binds up the free chlorine and keeps it from performing its sanitizing function if not used in proper amount.
Adding ozone to the water. Ozone as a secondary oxidizer destroys ammonia and nitrogen, preventing the formation of chloramines. As a disinfectant, this technique requires a large corona discharge ozone unit to disinfect. The unit works by injecting the ozone into a side stream (about 10% up to 25% of the water), and then returns it into the full flow.
Adding a UV system. First, note that UV-C doesn’t change the pH, turbidity, or alkalinity of the treated water. There are two main benefits working with UV: The first one is to damage DNA/RNA at a special wavelength of 254 nanometers, which damages depend on the UV dose expressed in mJ/cm2.
And seconf, many studies illustrate results before and after the addition of a UV system. Among the two UV technologies available, the medium and low pressure bulbs provide good results in regards to decreasing chloramines to acceptable levels in the water and in the air as well.
So now let’s compare the UV technology to remove chloramines against the “traditional” methods. Medium or low pressure units will remove chloramines in water and in the air,
- While requiring less treated and heated fresh water
- Avoiding the use of expensive non-chlorine shock treatment, while measuring the effectiveness of the combined chlorine level is not always accurate
- Chlorine shock can be time consuming and also inaccurate. Proper steps need to be taken when figuring out how much chlorine is needed for combined chlorine reduction. When using this method you generally have to close the facility. The current trend of commercial swimming pools is to be more concerned with their patrons health and well being while reducing chemical treatments
- Ozone has shown good results in removing chloramines, but it is expensive compared to UV systems. Ozone is also considered to be very hazardous and installation requires multiple alarm and emergency shutdown systems to be in place.
How to consider a good UV system! There are a couple of things to consider as all UV systems are not created equal. Are they GREEN? Are the units energy efficient? A reliable UV system is designed to handle a maximum flow rate. Check with your UV manufacturer about their certifications. A bad system will not do the job properly or completely so you are encouraged to ask for references. Some states have already done the job for you and maintain a shortlist of authorized systems.
When selecting a UV unit these are the key things to consider. Making the proper UV decision:
- Make sure to compare the wattage needed to attain good flow treatment. The wattage consumption between different competitors varies. For example, you will save more by getting a UV system which has an electronic ballast which prolongs the life of the UV bulb and uses less energy.
- In addition, there can be huge differences in regards to spare parts pricing per manufacturer
- Make sure to ask about required maintenance costs. Consider the number of bulbs in the system. Some UV systems may require substantial maintenance and require servicing for warranty program
- Two UV technologies are available: low pressure high output and medium pressure. Every pool is its own case. The facility usage, type of pool and bathing loads are all to be considered. For example, the needs for an indoor Olympic-sized pool with a heavy bather load will substantially differ from an outdoor medium-sized pool at a hotel. The UV technology needs to appropriately fit the environment.
Would you believe me now if I tell you that a UV system pays for itself in comparison to “traditional” methods of sanitization? And you will gain more in terms of the image of your establishment as you will be able to lower your carbon and water footprint which is the way it should go today.
