The Steripen Adventurer is an excellent choice for use in water treatment. It is light weight (3.5 oz) and will effectively and quickly rid water of viruses, bacteria and protozoa and protozoa spores. To use the Steripen, the instrument is activated and used to stir the water being treated. The stirring exposes the water to intense UV radiation which deactivates the DNA of disease organisms.
The problem with using the Steripen is stirring the water in most water bottles. Small neck water bottles will not accept the UV wand of the Steripen at all and wide mouth bottles still restrict the stirring motion potentially leaving some of the water untreated. I solved this problem by using a cut-off 2 liter club soda bottle as a water dipping, stirring and pouring container. The following photos show how it works.
First, pour a liter of water into the bottle and mark the level with a permanent marking pen. Make another line around the bottle an inch above the one liter mark and cut the top off along this line using scissors.
The resulting container weighs a bit under an ounce.
Heat the edge carefully and then pinch to form a pouring spout
To use, fill the container to the one liter mark, activate the Steripen and stir the water as directed in the Steripen instructions.
When you finish treating the water, pour the water into the drinking bottle using the formed pouring spout.
I store my stirring container by fitting it over the end of my rolled Thermarest Prolite 3
I use a fine mesh metal screen to remove particulate matter and always use chemical treatment if the water is turbid.