Plastic Bottle Desalination

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Introduction: Plastic Bottle Desalination

EDIT: In light of recent information " There's always a 'GOTCH' to a good idea isn't there....

With this system (and all systems that use plastics as evap-chambers/collectors) is that the plastic should be UV stable and BISPHONOL free.

Most plastics used in the drinks industries are not made for permanence in UV rich envirinments. Also, some of the temperatures generated in the evaporation base will radiate heat into the surrounding plastics helping to free toxic elements such as bispenol and other yucky plasticisers.'

I think that it is necessary to warn everyone NOT to use this device for anything other than exploring the basic principles of evaporation as a method of desalination (not that
 I genuinely believe that anyone would because the design really isn't that great .....) 

In my country (Australia) one of the biggest current issues is water conservation, and in some areas, the development of desalination plants. There are those who are for Desalination and argue that it will have a positive effect on rapidly diminishing water supplies. And there those who are opposed to it, becuase they don't like the idea of large machinery being operated near beaches and areas that have not been affected by development. Or, simply because they can't quite stomach the idea that drinking water may have previously played host to human excrement.

I'm all for desalintation, because i think that the benefits it offers are far greater than the problems tat it could cause. In this instructable I will show you how to modify a plastic bottle so that it can desalinate small amounts of water using heat energy from the sun.

Desalination: The removal of salt or other excess minerals from water through a variety of methods.


This is an entry into the keep the bottle contest, please take the time to vote, any support is greatly appreciated.

Step 1: Materials/ Tools

to build the bottle desalinator you will need:

Materials:
Large plastic bottle
tape (optional)
black paper (optional)

Tools:
cutting implements (I used a stanley knife and a pair of scissors, but you could use either on their own or something else i.e. exacto knife etc.)
Ruler
Black marker.

Step 2: Slicing and Dicing

There are two parts to the bottle desalinator. The main body, which is where the water is stored and the drain, which is where the water condenses and runs out and into the bottle/ cup that you want to drink from/ store it in.

The drain is cut from the upper half of one side of the bottle. Use a stanley/ exacto knife for cleaner, straighter cuts.

Step 3: Assembly

The assembly is quite simple.

Take the pre cut "drain", and place it at the base of the hole that it was left behind when it was cut out.
slot it throug the bottle so that it is on a small angle and secure with tape.

Step 4: Finished

To use the bottle desalinator, simply pour water into the base (there should be a gap between the drain and the sides of the bottle) and leave it out in the sun.



Further improvement:

To improve the efficiency of the bottle, wrap the base in black paper, tin foil or any other material that conducts heat well.

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17 Comments

If you were to push the top down so that the top faces the drain, would that not make the process faster? Concentrating the evaporated/re-condensed water towards the drain..

Could this be used as a solar powered still?

There's always a 'GOTCH' to a good idea isn't there....

With this system (and all systems that use plastics as evap-chambers/collectors) is that the plastic should be UV stable and BISPHONOL free.

Most plastics used in the drinks industries are not made for permanence in UV rich envirinments. Also, some of the temperatures generated in the evaporation base will radiate heat into the surrounding plastics helping to free toxic elements such as bispenol and other yucky plasticisers.

well that is one huge "GOTCH" :/ thanks for pointing it out.
I'll put a warning in.

thanks for all the comments! sorry I haven't replied though. I should mention that a lot of you have pointed out a fatal flaw in my design, the collection chamber, does not have a lid, or anything to stop the water evaporating out of it. This problem can be easily fixed however, by either adding a lid to the chamber and cutting a hole in it's side for the water from the evaporation chamber to come through. you could also paint it white to keep it as cool as possible. Once again thatnks for all the comments.

This is really cool. I knew you could desalinate by evaporation, but the mechanics of doing it with items you have on hand isn't always easy. Good description. For even faster results maybe try a black plastic garbage bag as a collector held up like a tent over a depression in the sand filled with saltwater. Of course, then you'd have to put something all along the edge of it to collect the fresh water.

Very cool, but wouldn't the distilled water evaporate from its container? Could you fix this by building something to hide the clean water container in the shade, but not dirty water container?

This is a great idea and I am sorry I am a bit "dense" on this. Do you put a smaller bottle of salt water inside the larger plastic bottle and the pure water condenses on that and drips?

This method also works for purifying water. In fact it can be a perfect method to purify urine in the desert since the hotter the better and the outgoing liquid is 100% pure H2O.