Tuesday, January 17, 2017

The Solar Still

Its as sure as taxes, whenever water treatment is discussed someone always says: 
"....I do not need that, I just dig a hole in the ground and cover it with plastic and get my water from there...!"

With a bit luck 0,0000001% of those writing that actually done it!

(And every time someone gives you an advise starting with "You just have to..." you should JUST RUN!)

The solar still really works, also here in central Europe. But there are to many circumstances which have to be just right to make this method  (in my opinion!) feasible.

First you have to dig a hole, since a solar still needs SUN this is (mostly!) work which will make you sweat.

Already there the price/benefit balance is askew...

Then you have to place a BRIGHT cup/pot in the middle of the hole, bright because:
It will be hard to see through even clear plastic due to the condensation. If you put a dark coloured pot/cup it will be near-impossible to see the precise location of it.
Which is important since you have to place a heavy object on the plastic sheet DIRECTLY above the pot/cup to allow the condensated water to drip into the right place.

That`s: Right over your cup/bucket/vessel

Use stones to keep the plastic sheet in place over the hole. I KNOW that every survival book in the market says that you need to seal the sheet hermetically to the ground with dirt or sand in order to reduce loss of moist air.

BUT: Removing the sheet without contaminating the water with dirt, insects on the inside or "dirty water" is an art...which I do not master.

The amount of water you lose when you filter dirt out of your water is several times larger than the few whiffs of moist air you lose by not "sealing it off hermetically".
If you have a length of rope you can coil it up around the hole ON the sheet: Easy and clean.

I started the still around 1000 this morning (CET, around 29 degree celsius) and finished it around 1600.

I got ca 200 ml out of my effort so I`d say: Not bad.

As you can see the water is not as clean as one was hoping for: Running it through a handkerchief will take care of that.

Still, this is my least favourite method of getting water, there are smarter ways of using condensation...which I will show...at some point of time :-)

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