Hey engineers, can you pasteurize bottles of water by leaving them in a hot car with the windows rolled up?

Question

How about an engineering perspective on this question I posted in Medicine?

When the huricane hits and there is no safe public water, how about putting some bottles of water in a car with the windows rolled up to pasturize it?

Please critically evaluate this idea. State reasoning clearly.

Here is a link on pasturizing water:
http://solarcooking.org/pasteurization/d...

And here is a link on how hot it can get in a car:
http://www.injuryprevention.org/states/l...

What factors would maximize the temperature. Which angle relative to the sun? Shades on the north side?

Above links didn't work. Second try below:
http://solarcooking.org/pasteurization/default.htm#Other_Devices

http://www.injuryprevention.org/states/la/hotcars/hotcars.htm

Answer 1

An interesting idea.

Neither of your links work for me, so I can't evaluate your
assumptions.

One source I found says
"Boiling is the most certain way of killing all microorganisms. According to the Wilderness Medical Society, water temperatures above 160° F (70° C) kill all pathogens within 30 minutes and above 185° F (85° C) within a few minutes. So in the time it takes for the water to reach the boiling point (212° F or 100° C) from 160° F (70° C), all pathogens will be killed, even at high altitude. To be extra safe, let the water boil rapidly for one minute, especially at higher altitudes since water boils at a lower temperature (see page 68.)"


I suspect you'll have a hard time getting the inside of your car up to a high enough temperature without modifying the car. I know the interior of my car doesn't get much over 140 degrees on the hottest summer days. To make the car hotter, insulate any part not in direct sunlight, and paint parts in direct sunlight flat black. If you can tilt them to be perpindicular to the sun's rays, that will help too.

I would think a solar oven built especially for this purpose would be better. Or even easier, a little Clorox goes a long way.

Answer 2

My compliments as well..Interesting idea.
A car in sunlight can be safely depended upon to get to about 140 deg. F.
Best take that, with the question, to "Biology" to find out
what 'little nasties` might survive.
I'd bet most won't, but wouldn't want to bet my health, especially in a situation where help might be hard to come by.

Answer 3

Hmmmm, maybe. I'm just not sure 150 degrees or so would kill everything, since it takes even a few minutes at boiling temperatures. I would stick with pump filters and iodine tablets.