How effective are solar stills at purifying water? Can you really just scoop up some lake water and use this method? Why doesn't the bacteria move along the surfaces? I heard that solar stills can even be used to distill gray water, is that true?
From what I have read and tried, you can use a solar still to get water out of just bout anything. You just have to make sure that there is absolutely no transfer of the original source of moisture to the drinking water.
Emergency kits on life rafts now contain solar stills so you can get drinking water out of sea water. http://www.landfallnavigation.com/memss.html
I have read where they were even used to get water out of blood. There is lots of info on the net, just type in solar still. It is probably worth having one or two in your kit.
I would take a fresnal lense, a heating rod, and a metal pan, weld the heating rod to the bottom of the metal pan, put water in it and prop it all up with heat resistant things like rocks... then heat the heating rod with the fresnal lense to boil the water...
If you use a still doesn't it just "steam" whatever liquid your putting in there... and typically isn't there a strong odor when you get steam from a pot? Does this indicate residue from the source liquid is being outputted?
There seems to be a lot of confusion about 'Solar Stills'.
What ANY still, solar or otherwise, does is condense moisture vapor back into liquid water.
YOU DO NOT HAVE TO BOIL THE WATER TO GET IT TO VAPORIZE.
Ever seen a cold glass condense clean, drinkable water on the outside of it sitting at room temprature?
Same principal, but we are capturing the water condensate.
You can use a plastic bag on a tree branch with leaves to capture and condense the moisture being expelled by the tree.
That is one type of 'Solar Still'.
You can put anything containing moisture in a container and put a water tight cover over it, set it in the sun, and it will 'Sweat' drinkable water.
Even poisonous plants will yield clean water in a solar still.
In the jungle during survival training, we simply used a hole in the ground with a plastic poncho liner over the hole.
The moisture in the ground provided more than enough water vapor to fill up a two quart canteen daily.
I use a table sized solar still to extract clean water for cooking when we were first starting to build at the river.
It was nothing more than a box with glass front face that angled to meet the sun.
The lower side of the glass made a natural drip edge, and a piece of PVC cut long ways made a good catch tray for the clean water.
River water, fruit/vegetable peelings, even urine can go into the 'Tank', and clean, drinkable water will come out.
The first one I made was out of cardboard and black plastic/clear plastic.
Once the 'Proof Of Concept' worked,
I built mine out of an old Formica counter top and use fiberglass boat hull repair resin to water proof everything.
I used half of a PVC tube as catchment and the bottom edge of face glass as drip edge, and it seems to work just fine that way!
So basically you take a water proof container at an angle. Seal a piece of glass to the top. Then you put a half piece of PVC to collect the water that drips off the glass. You then connect that PVC to a hose which runs into a storage container.
I am curious as to where the moisture comes from if the container is totaly sealed off?
Thje only ones I've seen were holes in the ground with a piece of plastic covering it and a pan inside to collect water.
Maybe I missed something!
The non potable water is in the bottom of the container. A clean, empty container rests above the water. Heated water evaporates and condenses on the roof of the container and drips into the clean, empty container. That seperates non potable from potable.
bassman, in the case of the solar still made from a hole in the ground, the moisture comes from the ground. In the examples JeepHammer provided, the water comes from grey water which is initially unsuitable to drink.
I've read somewhere that there may be some kind of pathogens left in the water obtained using a solar still (just as there are pathogens in the water falls from the sky). They were saying this is due to some pathogens being so small that they can hold to very fine water droplets, even when the water is in the form of fog. Does anyone has scientific information about that?
I'm sure you have heard of the new nanno technology.A professor at Missouri State University discovered this last year, I guess it will help us get 90-95% solar energy over the 20% now from solar products.Wow, right!