LOL, okay. I did cover solarization/SODIS, but okay.

They may have come up with a better version of the Steripen, but I recall seeing reviews that complained it tended to fall apart. Also, it uses batteries, so there's THAT issue. But otherwise, it works. However, as with solarizing/SODIS, the water MUST have low turbidity! (cloudiness). If there are any particulates, they really SHOULD be screened/filtered out. Otherwise the UV light can't do its job.

Most cities that use chlorine to treat their water have, or are, switching to chlorine dioxide. However, most bacteria only take about 10 seconds to kill with UV light, provided the light source is within about 6 inches. NY has the LARGEST UV (Ultraviolet Germicidal Irradiation to be exact) treatment system, San Francisco also has a massive UV system, so it could be a model for other cities/countries in the future. But as I said, UV works best IF the water is clear.