Ultra violet light is a popular choice to disinfect or eliminate microorganisms. In comparison to chemical treatment of water, UV light is often a safer, more environmentally friendly way to go as long as used or broken lamps are safely discarded.
UV lights need mercury, an extremely toxic chemical element. If old or broken lamps are trashed instead of being properly recycled or treated as hazardous material, mercury is released into the environment and can possibly leach into the soil and water. Many people are not aware of the threat that mercury poses to human, animal, and environmental health. Many people are not aware that their UV bulbs have mercury in them.
In Canada we have a few provinces that have government mandated programs for industrial and residential UV lamp recycling. Other provinces have third party non government organizations that take recycling into their own hands.
If you have a UV light in use, please make sure that when the time comes for replacement that your old bulb gets recycled or disposed of properly. Here at Rainsoft Eternally Pure Water Systems in Ottawa we collect all our clients old bulbs and dispose of them properly.
Recycling of Fluorescent lights: Not the same as a UV light but a good demonstration of what is being done.