One of the methods that can be used to purify drinking water in an emergency is UV light treatment. Maybe the process of UV purification is perfectly clear to all you microbiologists out there, but this has always been one of the more “mysterious” water treatment options to me. Really? You just swish this little light stick in your water and suddenly it’s safe to drink? Sounds a little suspicious. But it works. UV light is the method used commercially in most bottling plants and in hospitals and water treatment plants. It has been proven in studies to remove more than 99.9% of the microbes in water.
So let me share with you physics 101 on these UV light purifiers. I’ll try to keep it about 3rd grade level though, so I can understand it! There are ultraviolet light waves of various wavelengths in our world. Long lengths don’t have any effect on us, but the medium length UV rays are the ones that cause sunburns. The shortest UV wavelength light is extremely effective in killing viruses, bacteria, and protozoa–exactly the germies we want to eliminate from our water. What happens is the DNA in the microbe is disrupted by the UV light, so the microbe is unable to reproduce and make you sick. Unfortunately, these short UV wavelengths are filtered out of sunlight as it comes through our atmosphere, so to use them for water purification, they need to be produced artificially.
There are various large scale UV water purification systems out there, but for your personal preparations, an excellent option is a handheld UV purifier from SteriPEN. Mine is the SteriPEN Emergency.
The Emergency is able to purify up to 1 liter of water at a time. To use it, you’ll need the following:
- some high quality batteries–lithium ion or nickel metal hydride (NiMH). Don’t use standard alkaline batteries.
- water that is clear enough to treat. The light needs to get to the water to kill the microbes, so cloudy water doesn’t work. To get your water more clear, filter it through a coffee filter or fabric in an emergency.
- a container for your water. The SteriPen Emergency is made to work in a cup or similar container or in a water bottle.
To purify water with your SteriPen:
1. Get your water ready. You’ll need to know how much you have, so measure it if needed (we’ll come back to this in step 3.
2. Remove the protective cover from the UV light. At this point the two water sensors should be dry.
3. Push the button to start the SteriPEN. If you have 1/2 liter of water or less, you’ll push the button twice, if it’s between 1/2 and 1 liter, only push the button once. The green light will flash for 15 seconds.
4. While the green light is flashing, insert the UV end of the SteriPEN in your water. It will need to be inserted enough to get the water sensors in the water. the SteriPEN Emergency has a rubberized neck that creates a seal with a water bottle neck so you can insert it in a bottle and then invert the bottle to get the light into the water. The light will start working when it is in the water.
5. Swish the water around or swish the stick in your water so that all the water is exposed to the UV light for as long as the light is lit. When the light turns off, your water is safe to drink.
The SteriPEN Emergency is a lightweight, portable solution to water purification. Some of the reviews on SteriPEN’s site and on Amazon are from folks who have used SteriPEN products during expeditions to third world countries and had excellent experiences with it. So, put your skepticism aside (as I did) and consider a UV water treatment option for your water storage and purification preps.