UV (Ultraviolet) water purifiers use UV energy to treat water that contains bacteria and viruses. These purifiers are affordable, effective, and long lasting. They normally purify water in either 1 liter or 1/2 liter batches. Insert the UV tube in the water, activate the purifier, and swirl it in the water for about a minute. This treatment destroys the ability of the organisms to reproduce and renders them harmless. One manufacturer of UV purifiers is SteriPen.
Most water filters filter to between 0.1 and 0.2 microns. This level of filtration removes sediment, most chemicals, and most bacteria. This level will not filter all bacteria and all viruses. The UV filter renders these ultra tiny micro-organisms harmless. These purifiers are small, easy to use, and they purify water in about a minute. A UV purifier is an excellent choice when traveling to ensure that your drinking water is safe.
The UV purifiers do NOT filter the water and will NOT remove sediment, debris, and chemicals from the water. These devices last a long time (between 4,000 and 8,000 liters) but do NOT last as long as some of the water filters (such as the Sawyer filters). These purifiers require power so make sure to have spare batteries.
A UV purifier does NOT filter water. If the water contains chemicals, debris, or sediment then filter the water first. Most filters remove contaminants as small as 0.1 – 0.3 microns and some bacteria and viruses can get through. After filtering the water use the UV purifier to render those ultra-small organisms harmless. You can bypass the UV purifier by using a filter that removes contaminants down to 0.02 microns. If you use a UV purifier be sure the batteries are charged and keep an ample supply of spare batteries.