Ultraviolet (UV)

Ultraviolet (UV)

Ultraviolet Water Filtration Benefits

There are many benefits of using UV water purification systems, here are just a few:

• No need to handle potentially dangerous chemicals (chlorine)
• Virtually immediate disinfection (no contact tanks like chlorine)
• Low power consumption Environmentally friendly (no disinfection by-products)
• No moving parts to wear out or replace UV does not change the taste or odour of the water
• Lower equipment investment verses other disinfection options Simple maintenance (with proper pre-treatment).

Chemical vs. Physical Disinfection of Contaminated Water

• Disinfection is defined as “The act of disinfecting, using specialized cleansing techniques that destroy or prevent growth of organisms capable of infection.”
• Disinfection is a considered a 4-log reduction or equivalent to a 99.99% reduction
• There are generally two methods specifically for the disinfection of water:
  • CHEMICAL Disinfection: chlorine, ozone, iodine, bromine
  • PHYSICAL Disinfection: UV light, boiling, fine filtration

Chemical Water Disinfection

• If using chemical disinfection a chemical must be added in order to destroy the microorganisms present
• One method of chemical disinfection that we are most aware of is chlorination – specifically of our drinking water
• How does chlorination work?
  • Using a chemical such as chlorine will not only target bacteria but it will also change the taste of the water, the smell, the pH as well as possibly form disinfection by-products (i.e. trihalomethanes)

Physical Water Disinfection

• Physical disinfection does not require anything to be added to the water
• This method of disinfection targets the microorganism only
• Boiling, filtration, ultraviolet disinfection
• When the contaminated water is boiled only the microorganisms are targeted killing them as the temperature increases
• When the contaminated water is fine filtered specific microorganisms are removed depending on their size and the rating of the filter (i.e. Crypto)
• If UV light sterilization is applied only the microorganisms are targeted through DNA inactivation
• Using any of the above physical methods will not change the taste, odour or chemical makeup of the water
• One of the simplest and most effective ways to disinfect drinking water is by using UV disinfection

How Does UV Water Disinfection work?

• In theory UV disinfection is a simple process. The 254nm energy coming from the UV lamp needs to reach the target microorganism in the water supply. However, many barriers affect UV performance. These include:
  • Suspended Solids, both visual and not visual particulate matter (turbidity).
  • Scale, fouling caused by physical scale deposits on the quartz sleeve from iron, manganese or calcium carbonate covering the quartz sleeve
  • UV Absorbing Compounds, UV absorption in water is almost entirely caused by dissolved substances. Certain organic substances such as humic or fumic acids (tannins), and certain inorganic substances such as iron and manganese absorb UV.
  • These contaminants MUST be addressed for UV Treatment to be effective
  • UV is NOT a stand-alone treatment process and is always accompanied by other water treatment processes

Effect of UVC Light on Microorganisms

• Once microorganisms are exposed to UVC light they are rendered ‘inactive’ and can no longer replicate – meaning they can no longer produce colonies
• In the above picture on the left an agar plate is smeared with an untreated water sample, incubated & analyzed for colony growth
• The agar plate on the right has been smeared with a water sample that has been exposed to UV treatment – no colony growth occurred following incubation

Ultraviolet Water Treatment Options

Once a UV system is chosen for the home, the question arises as to where to install the system. Although you may only consume the water from one tap, the installation of a point-of-use (POE) UV may only be a wise choice if only one tap exists in the entire dwelling. For homes that have more than one tap, and that includes a bathroom faucet, the installation of a point-of-entry (POE) UV system will be the best choice for a whole home purification system. Insurance is the main reason for this logic as although you may never drink from that bathroom tap, but what if one of your guests happened to take a drink, or perhaps you brush your teeth and use water for that purpose. Safety and insurance is the prime reason to install a whole home UV purification system.

The Result = Pure, Safe, Environmentally Friendly Water with UV Disinfection

• Safe, reliable and easy to apply
• NO moving parts to wear out or break
• NO disinfection by-products (DBP’s) or residuals
• NO resistance as with chlorine and antibiotics
• NO regrowth of viruses, bacteria and parasites
• Lower capital investment when compared to chlorine or ozone systems
• LOW power consumption
• NO hazardous chemicals to store and/or handle
• Simple maintenance, only yearly lamp replacement (provided water quality parameters are met)
• Immediate contact time (no need for contact or storage tanks)
• NO change in water chemistry
• NO effect on taste or odour of water