Desalination

[chile1]

Greetings from Japan,

I'm a tutor in Kyoto Japan. I will be retiring to northern Chile in the near future. I have spent a considerable time searching the internet for a tried and true DIY desalination machine; something with a moderate capacity. I'm not looking for something free; I don't mind paying for parts and i love to tinker. I would even consider a commercial model in the 1 to 2 thousand dollar range. I haven't found anything like that and I suspect that if I haven't found it on the net that maybe it doesn't exist. Any information would be very much appreciated.

John Montpetit

[Fluxus]

I'm not sure of the costs, but look into boat desalination.

 

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=34025&catalogId=10001&langId=-1&storeId=11151&storeNum=10107&subdeptNum=10569&classNum=10526

 

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=34018&catalogId=10001&langId=-1&storeId=11151&storeNum=10111&subdeptNum=10628&classNum=10635

 

I suspect collecting rainwater and/or drilling wells will be more effective.

 

Also look into the "survivalist" stuff, if you expect to live "off the grid" and in a remote area.

 

And of course, before you commit you may want to talk to the people who live in that area, and see how they get their water and other supplies.

[Turtle]

we have a thread that might help you. :smilingsun: :cup: >> Solar Desalinator (Making one-- DIY + Serious Engineering)

[chile1]

I'm not sure of the costs, but look into boat desalination.

 

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=34025&catalogId=10001&langId=-1&storeId=11151&storeNum=10107&subdeptNum=10569&classNum=10526

 

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=34018&catalogId=10001&langId=-1&storeId=11151&storeNum=10111&subdeptNum=10628&classNum=10635

 

I suspect collecting rainwater and/or drilling wells will be more effective.

 

Also look into the "survivalist" stuff, if you expect to live "off the grid" and in a remote area.

 

And of course, before you commit you may want to talk to the people who live in that area, and see how they get their water and other supplies.

 

 

Thanks, your links are promising. Desal plants in the $3000.00 not too bad. My home in Chile is in a small village in the Atacama desert. The last time it rained in Pica was 16 years ago (7mm). There is a fresh water geo thermal spring; lots of fresh water, but I need something for my place on the coast. There is nothing for 30 or 40 kilometres north or south of me.

John

[seanster007]

 

Hello Tutor in Kyoto Japan John Montpetit

 

Three methods of separating salts from water. Two mentioned here so far. 1. reverse osmosis (filtering with pressure) 2. passive evaporation (incorrectly called distillation in some cases)

 

Number three: 3. distillation , which comes in two forms: A. simple heating and condensing and B. fractionating

 

You are looking at a DIY project. The lowest energy user is 2. For DIY you need containers, a pump, and the sun. If you are not generating solar electricity then you use wind power (either to generate electricity or to create mechanical energy. it is rare to find a place where it is both constantly overcast AND calm all the time, so one should suffice, if not both.

 

1. reverse osmosis is popular for three reasons. A. scalability . from tiny units that keep one person alive to massive industrial operations for cities, it works. B. lower energy costs. It costs less to make and power the pressure system on a commercial scale. C. portability. But for the same reasons, not so much a DIY project.

 

Method 3. A. distillation. It is simple but not energy efficient. You apply heat, boil the water, condense the vapours. Just the same as making alcohol. This is the easiest DIY project possible. You could make a "moonshine" type still in your back yard, burn scrap wood and get fresh water from sea water. Simple. However, hugely energy inefficient.

 

B. fractional separation. Slightly more sophisticated. Technically, building a fractionating column and pumping salt water through it, unheated, should eventually result, after repeated passes, in salt free water.

 

The same principle as a simple home 'water softener'. Again, not energy efficient BUT safer because there is no heat involved. A better system is a serial of fractionating columns, where the third of forth column can be used to 'repass' the liquid several more times.

 

This system will not work if the engineering of the columns is not absolutely precise.

 

SO, in the end, the easiest thing to do is build a simple old style moonshiner's still, put up a windmill or solar panels, generate electricity, heat an electric burner, boil the stuff, condense off the vapour and you have fresh water.

 

Look into these links:

 

Distillation: http://www.docbrown.info/page01/ElCpdMix/EleCmdMix2.htm

Seawater greenhouse: http://en.wikipedia.org/wiki/Seawater_greenhouse