Low, fixed running-cost – the UV light has a lifetime of 12-months and the quartz tube has a lifetime of 24-months no matter how many liters of water are purified (if proper pre-treatment is in place)
No chemicals are added to the water
Fairly Easy DIY Installation
There is no residual disinfection effect of the water – unlike chlorine or ozone, the UV light will only sterilize the water in the UV light. This means that it is essential to ensure that the pipes or vessels that the water flows through are clean as any bacteria that is introduced after the UV light will remain in the water.
Power is required to run the UV light, so if there is not a power source nearly, one will have to be installed.
Water with a high turbidity (water that is murky with many suspended particles) cannot be so easily penetrated by the UV light, so the UV sterilizer will be less effective.
Any suspended particles in the water (including those released from other filters) will reduce the UV lights effectiveness. Because of this we usually recommend installing a 1-micron sediment filter ahead of the
UV light to remove any particles.
What factors influence a UV sterilizer’s effectiveness?
Size and type of organism: Theoretically UV radiation can kill viruses, bacteria, algae, and protozoa. In general, larger organisms, such as protozoa, require a higher dose of UV radiation than smaller organisms, such as bacteria. But there are also differences between various organisms of the same type: some bacteria are more resistant to UV radiation than others.
Power of bulb: The amount of UV light produced by the bulb is indicated as the wattage of the bulb. Bulbs with a higher wattage produce more UV light. The ability of the germicidal fluorescent lamp to produce UV light decreases with age, and in most cases, the bulb needs replacement every 12 months. UV light is best produced at temperatures of 40-43?C; cooler temperatures will result in less output.
UV penetration: If the UV light can not penetrate the water, it will not be effective. Higher water turbidity will decrease penetration. UV sterilizers should be placed after the biological and mechanical filters so the water is as clear as possible when it enters the sterilizer. An additional small sediment filter before the UV sterilizer is also recommended if there are any doubts about suspended particles being present in the water. Finally, cleanliness of the lamp or sleeve is important. If a film or mineral deposit covers the lamp or sleeve, the light will be partially or totally blocked.
Contact time: The longer the amount of time the water is being exposed to the UV light, the more killing power is available. The contact time, sometimes referred to as “dwell time,? is influenced by the flow rate of the water: slower flow rates increase contact time. The length of the bulb also affects the contact time; with a longer bulb, the water is in contact with the UV light for a longer period of time.
Temperature: UV light is best produced at temperatures of 40-43?C; cooler temperatures will result in less output. Quartz sleeves help to insulate the bulb from the cooler water and thus maintain a higher UV output.
How is a UV sterilizer installed?
The UV sterilizer should be the last piece of equipment in the filtration system before the water runs to a house or is used at a tap. It should be preceded by biological and mechanical filters and any chemical filter that may be required in the system. Follow the manufacturer’s directions on installation or watch our video on correct the installation procedure.