Bacteria, cysts and viruses are all around us, but exposure to harmful ones can lead to sickness. UV Water Treatment Systems are the most popular method for killing micro-organisms in water and are commonly used with private water supplies like a borehole or well and to treat mains water. This type of treatment tackles biological issues without changing the chemistry of your water, making it friendly for both the consumer and the environment.
How Does A UV System Work?
UV Water Treatment Systems use a ‘reactor chamber’ to pass the water along a UV lamp which emits Ultra-Violet light. The natural properties of Ultra-Violet light disrupts the DNA of any micro-organisms in the water. This destroys their ability to function normally and reproduce – in turn stopping them from being able to make you unwell.
Because UV treatment does not change the properties of the water or produce any by-products it is often a preferred option to other methods of water treatment such as chemical dosing.
What Types of Micro-Organisms Can Be Treated With UV?
UV Treatment of water is effective against a whole host of micro-organisms, here are some you may have heard of:
- Dystentry Bacilli
- Fecal Coliform
- Polio Type 1
- S. Paratyphi
Why Use A UV Water Treatment System?
UV Treatment is the most popular method for the treatment of micro-organisms in water due to its many advantages and few drawbacks. You can see from the pros and cons listed below why it is often preferred over other methods such as Chlorine dosing which is known to have adverse health effects.
Pros Of UV Treatment:
- Effective against 99.99% of micro-organisms
- No change to water properties such as temperature and pH
- Fast disinfection with little processing time
- Low carbon footprint compared to other methods
- No storage or handling of harsh chemicals
- Easy to install and maintain
- No byproducts produced
- Low running costs
Cons Of UV Treatment:
- Electricity is required to power the UV System
- UV is only effective at treating micro-biological issues
- Sediment in the water can cause ‘shadowing’ of UV light preventing effective treatment – this is easily overcome with the installation of a sediment pre-filter
Where Are UV Systems Commonly Used?
- UV Systems For Swimming Pools – Swimming pools can harbour a significant amount of bacteria, even with regular Chlorine dosing. Often a UV system is installed on the filtration loop to assist in controlling biological growth.
- UV Systems For Drinking Water – Drinking water systems of all shapes and sizes can include a UV system to destroy bacteria and other micro-organisms. UV treatment of private water supplies (like a borehole or spring) is required and forms part of an Environmental Health Officers inspection. UV systems are increasingly common in homes with mains water as consumers are becoming more aware of what is in their drinking water.
- UV Systems for Aquatics – Commonly used within the aquatics industry for controlling biological growth (such as algae) in both tanks and ponds. Usually installed as part of the standard filtration loop allowing for a constant ‘side stream’ of water to pass through the UV and treat the water over a period of time. In marine water applications, it is recommended to use a plastic reaction chamber over a stainless steel chamber due to the potential for corrosion.
- UV Systems For Post-RO Applications – Part of the requirement for feeding an RO system is removal of Chlorine from mains water as it can cause damage to the RO membrane. Once the chlorine is removed there is nothing in the water to prevent biological growth – for this reason it is recommended to have a UV system installed after an RO (or RO storage tank) particularly where the water may come into contact with food, in beverage applications and where RO water is used for misting.
Specifying A UV System
When specifying a UV system the most important thing to consider is the flow rate. The slower that water flows through the reaction chamber the higher the UV dosage, or the faster the flow rate the lower the dosage. Most UV systems on the market will have a specified flow rate that allows for industry standard dosage rates.
It is always best practice to select a UV with an advertised flow rate the same or slightly higher than your flow rate and to be aware not to ‘over size’ as without enough flow the lamp can overheat.
Other Important Factors To Consider:
- Connection Sizes – The connection or port sizes of each system can vary (usually between 3/4″ and 1.5″ BSP) so it is important to check that you can connect the system to any pre-existing pipework.
- Visual And Audible Alarms – Many systems like our Ultra UV range come with an audible and visual indicator that gives an at-a-glance insight into whether the system is operating correctly. Our commercial systems also include a high temperature shut-off to prevent overheating.
- Location Of The Installation – Whether the system will be installed either inside or outside should also be considered. It is recommended to keep the UV as close to the point of use as possible, to ensure effective treatment of your water.
- Reactor Chamber Material – The material of the reactor chamber is critical for salt water applications where a plastic chamber should be chosen over a stainless steel, due to the potential for corrosion.
What Maintenance Does A UV System Require?
UV systems are one of the easiest types of water treatment system to maintain. With a clearly defined maintenance schedule that is similar between most brands on the market.
All UV systems should have a sediment pre-filter, which is usually 5 micron. This is to reduce sediment and prevent the potential for particulate passing through the system and causing ‘shadowing’ of the UV light (where a micro-organism may ‘hide’ behind particulate and not be treated effectively). This sediment filter should be changed every 6-12 months depending on the quality of the feed water.
Bulbs And Sleeves
UV bulbs have a limited lifespan, usually around 9,000 hours of operation. It is best practice to replace the bulb after reaching the maximum hours of usage or every 12 months, whichever comes first. The bulb has a quartz sleeve surrounding it, which should be wiped clean every 3 months to prevent biofilm or sediment build up that could cause shadowing. Quartz sleeves are notoriously delicate, so care must be taken when handling them. Many customers find it easiest to order a spare quartz sleeve when ordering a replacement bulb so that they have it on hand should it get damaged during bulb replacement.
Which UV System Is Best?
UV systems are usually categorised by their capacity or target market, such as domestic or commercial applications. For this reason, the best option really comes down to your requirements and expectations. The most important thing to consider is your flow rate to ensure the right amount of UV exposure for your water to be treated effectively.
If you need any assistance in choosing the right UV Filtration System for you then why not give us a call, drop us a message on live chat or send us an email where we would be happy to assist.