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Ultraviolet disinfection 


Reliably providing safe drinking water

EPCOR utilizes advanced technology like ultraviolet disinfection to provide safe and reliable drinking water.

  • In 2002, we installed what was then the world’s largest UV system at the E.L. Smith water treatment plant in Edmonton and with the installation of a UV system at the Rossdale facility, the Capital region now receives the full benefit of UV disinfection.
  • In 2002, we also completed the installation of a UV system for the Town of Canmore, making it the first community of its size in Canada to employ UV disinfection for water treatment.
  • EPCOR has shared its knowledge of UV disinfection with a number of other communities, including New York and the Greater Vancouver Regional District.

An environmentally sound process

UV disinfection is a safe and environmentally sound process.


Using intense beams of ultraviolet light, UV disinfection systems inactivate protozoa, bacteria and viruses. UV is very effective against cryptosporidium, a protozoa resistant to traditional chlorine disinfection methods.


Through extensive research and rigorous field trials, UV disinfection has proven to be safe, reliable and inexpensive. These benefits have motivated utility owners worldwide to re-evaluate their current method of drinking water disinfection and implement UV systems.


UV technology can be added to almost any existing treatment plant and can provide up to 1,000 times the current safety factor for certain pathogens in an environmentally friendly and cost-effective manner.


Basic UV treatment process at E.L. Smith

Intakes – After being treated with chemicals, such as fluoride and ammonia, the water enters the newly constructed UV facility. In the past this flume ran straight to the reservoirs, but the pipe has been re-routed in order to incorporate the UV technology.


Reaction units – Water entering the UV facility proceeds to split into three identical units each housing UV lamps. Flow meters within the base of the units serve to monitor how much water passes through them. The information received is essential in determining the correct dosage of UV light to apply to the water. Two reactors can handle the maximum output of the E.L. Smith plant, but the third allows for maintenance work to be done without interrupting the water treatment process.


UV lamps – Each unit has 6 high powered, medium pressure UV lamps that, taken together, can receive up to 2600 Volts of power. When activated they penetrate the water in all directions with a dose of high-energy UV light. The lamps work in banks of 2 and if one lamp fails the whole bank shuts down and the standby bank is remotely activated. At any one time only two out of the three banks of lamps are used. For protection, a quartz sleeve covers these valuable lamps.


On-site reservoir – UV treated water leaves the reactor and, if necessary, is further treated with chlorine and other chemicals. It then leaves the UV building and reconnects with the original flume that leads to the on-site reservoir.


Automation – Automated operations and safety controls allow for minimal operator attendance. For example, if a lamp extinguishes, a Smart-start back-up lamp is automatically engaged. And UV sensors ensure that the optimal dose of UV is applied to the water depending on factors such as the amount of water that enters the reactor and how clear the water is.


How does ultraviolet work?

Strong light (UV energy) disinfects water by permanently de-activating the DNA structure of pathogens, like Cryptosporidium, and in so doing prevents them from multiplying further. The key to UV technology is making sure the organisms in the water are exposed to enough UV light that they will be unable to reproduce. Unlike chemical disinfectants the organism is unable to develop any immune mechanisms to this treatment.


How effective is this treatment?

UV technology improves our ability to treat water for a variety of pathogens and in combination with other treatment processes, like chlorination and filtration, provides a multi-barrier approach to water treatment. This treatment makes it possible to destroy more than 99.99% of all pathogens in the water. And it is estimated that this treatment allows for 100-1000 times better removal of Cryptosporidium parvum.