How
is Ultraviolet Light
Used to Purify Water?
What
is Ozonation?
Ultraviolet Light:
Ultraviolet light systems make use of the
ability of this portion of the light spectrum to kill bacteria. Such systems are
only effective on bacteria, viruses and some algae. This technology does nothing
about eliminating protozoa such as cryptospordia and giardia. The lights are
normally combined with carbon technology to give more complete purification.
Other drawbacks are:
- Incomplete purification:
Particles in the water like dirt, leaves, etc. can prevent the disinfection
process from hitting every bacterium, etc.; some can slip through in cases
of heavy silt and sediment levels.
- No residual disinfection
down the line: The process is only good at the spot where the light is
located; any contamination down the pipeline is picked up as the water
continues down.
- Limited application: UV
light is good only for bacteria. It does nothing about giardia,
cryptosporidia, chemicals, lead or asbestos.
- Expensive to purchase
and maintain
Ozonation:
Ozone units super-oxygenate water which kills
bacteria with adequate contact time. Again, this is a process that only
addresses bacterial contamination and so is necessarily combined with carbon
filtration to be most effective.
Other drawbacks are:
- Expensive to purchase
and maintain
- Create by-products in the treated water:
Ozonated water can contain high amounts of toxic
contaminants, such as formaldehyde, formalin and different aldehydes. Some
of the created by-products also allow for increased bacterial growth in the
pipes down the line which contributes to re-infection of the water.
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