Friday, January 28, 2011

Solar Water Disinfection

Just ran across this info and had to share. Check out SODIS!

"The SODIS method is very easy to apply: A transparent PET bottle is cleaned with soap. Then, the bottle is filled with water and placed in full sunlight for at least 6 hours. The water has then been disinfected and can be drunk."

9 comments:

tffnguy said...

Abby, that's good to know and in a pinch I'd use it. I'm running low on drinking water now, but will probably take a trip south to get my 7 gallon jug filled though. I wonder why PET bottles and not glass bottled? Seems like if it works for PET bottles it would work equally well for glass bottles.

Abby said...

http://www.sodis.ch/methode/anwendung/factsheets/glass_pet_e.pdf

Glass is fine! It's just breakable and heavy :)

tffnguy said...

I've seen where people also use PET bottled for solar heating. They stack them in an area where the sun can shine on them through the day and then when nightfall comes they give up the heat to warm the area they are in. I've used them for solar heat by drilling a hole in the bottom where the threaded area of another one will just fit in that hole. Then running black pipe through a series of them and circulating water / antifreeze mix through it. Works pretty well especially when you put foil reflectors on the back side to reflect all of the sun's rays on the pipe. I used CPVC for that once and it got so hot that the CPVC melted.

HermitJim said...

Isn't it great how we can learn something every day on these blogs? What a wealth of information we can share with each other!

jandean said...

Recent studies have shown that reusing bottles made of PET can in fact be dangerous. PET was found to break down over time and leach into the beverage when the bottles were reused. The toxin DEHA also appeared in the water sample from reused water bottles. DEHA has been shown to cause liver problems, other possible reproductive difficulties, and is suspected to cause cancer in humans. Therefore, it's best to recycle these bottles without reusing them.

jandean said...

P.S. I'm not advocating for single-use plastic bottles. I think it is best not to purchase them in the first place, since they are petro-intensive. Glass sounds like the way to go here.

Abby said...

David, I remember reading something MANY years ago in the Mother Earth News about someone using big barrels painted black and filled with water for solar heat - they just sat in the house where the sun came in the windows on them all day.

Jim, got that right! I love reading about what other people are trying out and what works and what doesn't.

Jan, I'm also not a fan of plastic. It's good to know that a day or two in the sun will kill the crawlies in water, though. I think I'd want to filter out the chunks first, then sun treat it.

tffnguy said...

Abby, the people that use the clear bottles for solar heating put something in the water, but I don't remember what. The particulates float in the water and the sun hits them causing them to heat the water. Water like distilled water doesn't do near as good because a lot of the sun light just passes through without heating it that well. The black barrels work good, but the sun only hits one side and doesn't pass through the water so they may not be as efficient?

Jim H. Moreno said...

We did this in the Army, with the additions of wrapping the spout with a coffee filter, and dropping a couple iodine tablets into the water. Worked very well in a pinch.