UV light is used to filter water all over the world. From filtration systems in domestic properties and ultraviolet water bottles to large scale UV lamps purifying wastewater in treatment plants, the technology is growing in popularity everywhere.
Which is hardly a surprise. UV light can disinfect bacteria in water just as effectively as chemicals such as chlorine, but with none of the effects on water quality that potentially come when introducing such compounds.
How does UV light purify water?
Ultraviolet rays can penetrate harmful pathogens in water, attacking their DNA and ultimately destroying them. The technology is effective on all kinds of diseases and viruses which thrive in water supplies, including E. coli, cryptosporidium and giardia.
As water passes by UV lights, these rays instantaneously neutralise harmful microorganisms. It is a quick and easy way to remove 99.99 percent of bacteria found in water.
Where is UV water filter technology used?
UV water filter technology is as effective for domestic homes treating water as it is when introduced in wastewater treatment facilities responsible for purifying sewage before it is returned to nature.
Properties which draw water from a private well or reservoir which has not undergone vigorous treatment are often advised to use UV light as a cost-effective way of treating their water. By installing a UV system at the point of entry, ultraviolet lights can disinfect the supply for an entire home.
Wastewater treatment plants utilise UV lights at various points during the water purification process. With improvements in technology, it will become easier and cheaper to utilise the power of UV in large-scale water filtration.
In December 2020, United Utilities announced that their site in Cumwhinton, near Carlisle, was to become the first in the world to have LED UV lights installed on an industrial scale. LED UV lights had previously been restricted to small amounts of water at low flows and domestic use.
Six LED reactors were to be constructed by United, significantly reducing energy consumption at the site compared to traditional UV lights, and increasing asset capacity.
What are the benefits of UV water filtration?
The major benefit of using UV light to filter water is that it is a chemical free method of purification. It does not leave any harmful by-products, nor will it impact on the taste or odour of water being treated, as chlorine would.
Because of the safety advantages of UV over chemical treatment, many wastewater treatment sites are switching from using chlorine to ultraviolet light for the better protection of their employees, the environment and the communities they serve.
As laws governing the treatment of wastewater and the role that chemicals play continue to change under pressure from environmentalists, adopting UV disinfection allows companies to be well-suited to meet stricter regulations in the future.
UV water filtration also offers financial benefits. It is the only cost-effective alternative currently available to chemical treatment.
What are the limitations to UV water filtration?
Whilst UV light kills 99.99 percent of bacteria, this alone is not enough to make water completely safe for drinking purposes. UV light does not remove other contaminates such as heavy metals and volatile organic compounds (VOCs).
To purify water to safe drinking standards, UV water filtration should be used alongside other forms of filtration such as reverse osmosis systems or carbon block filters.
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