Interesting article about disinfecting drinking water by exposure to sunlight. I had never heard of this simple method before, although I was aware of UV treatment of water supplies. I presume one would have to leave it out longer, the farther away from the equator you are.

Link

-- John (jh@NotReal.ca), November 15, 1999

Answers

I've read in general the time length in the direct sun should be five hours and the water bottles need to be on a black cloth. I assume that is different and possible based on geography. I had recently read about this method myself and rushed down to Smart & Final and picked up 32 ounce Kerr canning jars with lids "just in case." One thing that excited me was that if I can't restock on some purification tablets, fuel etc for 2001 I do have this method as a possible alternative. If one became a refugee this method has some potential.

I also liked the idea that I could have warm water to use for bathing without draining my camping stove fuel.

I am amazed at your self control to ponder and question. I was out the door to buy the largest jars I could find so fast it made heads spin. I just need a big black cloth now. To WalMart I shall go!

-- Paula (chowbabe@pacbell.net), November 15, 1999.

Re: I am amazed at your self control to ponder and question.

I have an RO (reverse-osmosis) filter on my normal water supply from the well. As long as I can get enough gasoline to run my generator for brief periods to pump water once or twice a day, I should have enough water pressure to use that method.

Failing that, I guess it's sunlight or chlorine.

-- John (jh@NotReal.ca), November 15, 1999.

Good post.
Note that the time required is, as they say, dependent on exposure, which varies according to location, time of day, cloudiness. Also altitude. There is more UV at higher altitudes, lower (closer to equator) latitudes, mid-day, and clear days.

The study was done in Beirut, which is at (all latitudes I give are approximate only) 35 degrees North latitude. Los Angeles, Calif is similar. Buenos Aires and Sydney are about 35 South. New York at 40 North. London and Vancouver, BC, at 50 North. Since most people on this forum are most likely at 35 degrees north or higher latitudes, the exposure times for sterilization should be increased substantially. (How much, I don't know -- maybe a careful re-reading of the article will "shed some light.")

-- A (A@AisA.com), November 15, 1999.

If the sun heats up any more there's going to be some THOROUGH solar disinfecting going on .....

-- SH (squirrel@hunter.com), November 15, 1999.

Thanks.

Like "natural" options.

Diane

-- Diane J. Squire (sacredspaces@yahoo.com), November 18, 1999.