[pct-l] SODIS - Solar Water Disinfection

[vet@schroll]

Does anyone have experience with solar water disinfection - SODIS?
Water should be exposed for 6 hours in PET bottles at sunlight - UVA - which
has the same effect as Steripen, only cheaper and no batteries.

I think that it is maybe not very practical to carry water for 6 hours on
top of the backpack, horizontally, but I am interested anyway if someone
tried this method, maybe as backup?