wrote:
On Aug 8, 5:35 pm, "HeyBub" wrote:

Right. You can put almost any (relatively clear) water in a clear
plastic bottle, put the bottle in the sun for a few hours, and,
presto, sterilized water.

How effective? What % of bacteria will simple sunlight kill in a few
hours? Thanks for the tip. I'll try that and retest it if you don't
respond and hopefully post the results here.

There's bags of studies on this concept. Here's one:

http://www.icross.ie/publications/pd...nfection_1.pdf

"In-vitro studies carried out at the Royal College of Surgeons in Ireland
confirmed the bactericidal effect of solar radiation and showed that
transparent plastic bottles allow passage of more ultraviolet light than do
transparent glass bottles. Although glass transmits ultraviolet light more
readily, the thinness of plastic bottles compensates for plastic's greater
absorption of ultraviolet light. This finding suggested that non-returnable
plastic bottles, which are widely available and even a source of pollution,
may be used for the disinfection of drinking water."

The authors consider this experiment utilizing little brown babies in Kenya
as a follow-up to an earlier study that relied on the heating effect of
sunlight for disinfection.