Ultraviolet Water Disinfection

UV water disinfection is an increasingly popular and commonly used water treatment technology that leaves no taint, chemicals or residues in the water. Disinfection using UV light is a method used in a range of environments such as water, air and on surfaces. It is quick and clean and no bacteria, viruses or moulds are immune to the power of UV.

UV disinfection systems, also called ‘UV sterilisers’ or ‘UV water filters’, comprise of a stainless steel reactor chamber housing, UV lamp or lamps and the protective quartz sleeves that the lamps sit in. The quartz sleeve normally separates the lamp from the water to prevent the lamp from cooling. The micro-organisms in the water are exposed to UV light generated by a UV lamp enclosed in a stainless steel or (less commonly) plastic chamber. The UV breaks and modifies the DNA contained in the cells of the organisms, stopping the bacteria from reproducing and effectively killing it.

UV water treatment is widely used in the following specialist areas: 

• Industrial and Commercial
• Residential Drinking Water
• Effluent Disinfection
• Swimming Pool and Display Water
• Water Filtration
• Aquaculture
• Horticulture and Hydroponics
• Water Recycling
• Rainwater Harvesting

All private water supplies must meet relevant regulations, specifically The Private Water Supplies Regulations 2016 for England, which include quality standards to ensure that the water is pure and safe to drink. 

A UV Lamp is the heart of the UV treatment system. The lamp needs to operate well to ensure water is safe. Unlike regular light bulbs, UV Lamps do not burn out – they solarize. This means that over time they reduce in their light wave intensity to about 60% of what a new UV lamp provides. This point is reached usually after one year or 9000 hours of continuous use. It is EXTREMELY IMPORTANT to replace the lamp every year on schedule or after 9000 hours of operation. 

Since UV radiation must reach the bacteria to inactivate them, the housing for the light source must be kept clean. The treated water should be monitored for coliform and heterotrophic bacteria on a monthly basis for at least the first 6 months of the device’s use. If these organisms are present in the treated water, the lamp intensity should be checked, and the entire plumbing system should be disinfected.

It is most likely that, in addition to the protection given by the UV disinfection system, a further regime such as temperature monitoring is employed against Legionella bacteria (as advised by the Health and Safety Executive’s L8 code of practice). 

Quick Facts about UV Water Treatment

• UV is effective and quick. No need for holding tanks and reaction times. No need for storing chemicals.
• UV does not alter the taste of water, which makes it ideal for use in bottling plants and food processing applications.
• UV is safe. NO need to add or handle hazardous chemicals or risk polluting the environment.
• UV is compatible with all other water treatment processes. No need for de-chlorination if using RO systems. 
• UV is economical. Almost always, the cost of UV disinfection units is much less than the cost of chemical treatment systems. 
• UV is more effective against viruses than chlorine.
• Easy installation. UV units are very easy to install and require very little space.