Water Treatment - UV light

Water Treatment - UV light

   One of outdoor equipment I got before is a water treatment with UV (Ultra Violet) light.  The idea of this is to kill almost all bacteria, viruses and protozoa.  The advertisement says 99.9%.   They have some data to show it works.  Typically, I am using a filter type purifier when I hike.   Actually, I did not have a chance to use this even if I own it.

   There are a couple reason I did not use:

1. If I camp on a trail, the amount of water I need is not small amount.  It only takes care of 1 litter of water at one time.   Therefore, if I need a few litters and water for the next days.   It will be a several litters of water.   To process such amount of water with this is not really efficient.  The filter type is probably much convenient.
2. I have never seen people who use this type of water purifier on a trail.   I guess the experiment data the vendor shows is probably true.  However, some of my friends had some questions if it really works or not.  Another words, people could not completely believe this product.

   On the other hand, here is the reason I got this product:

1. I thought it would be convenient to get some water other than a camp site.  Just getting some water on the way to a destination.  It won't be a lot of amount and this might be convenient other than using the filter type (pump type) in that situation.
2. The filter type won't be able to cover everything.  Especially viruses might be too small to filter them out.  So it is probably safer to use this type of product if I need to drink without boiling.

   In a reality, I typically have enough water of a day and I do not have to take extra water on the way.  Also, I have been using the filter type water treatment a several years and I did not have much problem in the past.  So I did not really think I really need such extra treatment.  I think people in the United States is safer side and the water treatment is much more popular than Japan.  On the other hand, at least when I was in Japan, the water treatment was not really popular and I had never used it on a trail.  Even though, I had never had any major issue without any water treatment.   I guess it is probably all right most of cases, but people recommend to use it just in case.  It is probably better to avoid any risk on a trail.

   As my conclusion, I probably won't use it proactively in the future anyway.   However I am curious if there is any way to check this is useful or working all right.   Currently I do not have much idea how I can verify this function.   But I just wonder if there is some good way to verify this.

   Does anybody have any idea about this?  

   I started thinking about this because I found it when I clean my outdoor equipment box this weekend.   I found it and I know I have never used.  I might try something in the future.