UV Water Treatment: EPA Certified Technology
Ultra-violet (UV) water treatment is the purification process of letting water pass by a special light source. Plunged in the water in a protective transparent sleeve, the special light source radiates UV waves that can destroy harmful microorganisms. This mode of treatment is increasing in popularity because it does not specifically need the addition of chemicals.
The ultra-violet rays, almost the same as the sun’s UV but stronger, affect the nucleic acid (DNA) of viruses, bacteria, moulds or parasites, so that they will not be able to reproduce and are considered impotent. UV water treatment does not change the water chemically because nothing is added except energy. It should be observed that the killed microorganisms are not segregated from the water. UV water treatment does not eliminate dirt and particles, metals such as lead or iron, or hard minerals such as calcium. Other devices are needed to remove particles, metals and minerals.
UV-treated water is safe to drink. UV water treatment does not add chemicals or alter the chemical composition of the water. When sized properly and placed on a visually clear water source, UV can efficiently protect against microorganisms in the water. Prolonged storage of water after UV treatment is not advised.
There are different types of UV water treatment systems. UV water treatment systems are present to treat all possible flow ranges, from small point-of-use applications to vast municipalities. For household applications, a point-of-use or point-of-entry UV system can be utilized. A point-of-use system is a small, portable device that is attached to a faucet and rests on the counter. It can also be attached under a counter. Larger point-of-entry systems are also available in the market which is installed where the water supply enters the household and disinfects the entire water supply.
Class A systems can be both point-of-entry and point-of-use (large or small. They are created to kill and/or remove microorganisms including bacteria and viruses. However, they are designed to be installed on visually clear water (not coloured, cloudy or turbid water) and not for transforming wastewater or raw sewage to drinking water.
Class B systems can also be point-of-entry and point-of-use systems (large or small). However, they are designed to supplement bactericidal treatment of disinfected public drinking water (i.e. city supplied water) or other drinking water that has been tested and proven acceptable for human ingestion by the provincial or local health agency having that authority. They are created to reduce bothering microorganisms and are not intended for disinfection.
A UV water treatment system consists of the following:
- UV light source which is called a “lamp” or “bulb”. Class B UV systems typically give a dose of 16 mJ/cm2, and are usually preferred by people to municipally treated water or private water supplies which are considered to be unsafe. Class A systems deliver a dose of 30 to 40 mj/cm2, enough to be utilized in water supplies which are likely to be unsafe.
- Protective transparent housing for bulb – usually quartz
- Power supply
- A water chamber for the water to travel through for treatment
- Filters for pre and/or post-treatment
- There may be a bulb replacement indicator light and/or alarm for larger class A systems.