Ultraviolet Water Disinfection

What is UV disinfection?

Ultraviolet 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 separates the lamp from direct water contact 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

How ultraviolet water disinfection works

Ultraviolet water disinfection works by utilising UV light emitted mainly at 254nm (billionth of a metre) by UV lamps in specially-designed systems. However, light between wavelengths 254 and 265nm may be used for specific disinfection applications.

All biological species require different exposure levels to UV light to inactivate them, some like Legionella Pneumophilla, will die at relatively low exposures, other like pseudomonas, are more robust and do require a higher dose of UV light to inactivate them.

A major advantage of UV treatment is that it is capable of disinfecting water faster than chlorine without cumbersome retention tanks and harmful chemicals. Ultraviolet disinfection water treatment systems are also extremely cost efficient compared to some other alternatives.

UV Lamp Replacement and Maintenance of a UV System

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 ultraviolet disinfection services. 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 ultraviolet disinfection water treatment 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.

Comfort Services Group can provide the servicing and maintenance of the UV units and replacement of the UV lamps as per the customer’s requirements. We offer a free, no obligation initial quotation and would love the opportunity to chat with you about your needs and how we may be able to help you with our ultraviolet disinfection services.