How to Build a Desalination Watermaker

With increased global concern over the supply of fresh water, governments, private industry and development agencies have been exploring a variety of technologies aimed at efficiently producing potable water. One of those methods, desalination, involves the removal of minerals from salt water through various processes. While methods like reverse osmosis have been criticized for being quite energy intensive, you can also build your own solar-powered desalination unit using common materials, a simple and environmentally-friendly solution to the lack of fresh water.

Things You'll Need

• Shovel
• 2 Polythene (plastic) sheets
• 1 Gallon bucket
• 1/4-pound weight
• Salt water
• Stakes

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Instructions

• 1

  Dig a large hole in an area with good solar exposure. The hole must be at least twice as deep and have three times the diameter as your bucket.

• 2

  Line the hole with a polythene sheet, completely covering the bottom and sides of your hole and holding the sheet in place with stakes or rocks. Use rocks to hold the sheet in place inside the hole, being careful not to puncture the sheet.

• 3

  Clean the second polythene sheet and the inside of your bucket, the surfaces that will come into contact with the potable water, very well.

• 4

  Place the bucket in the middle of the hole.

• 5

  Fill the hole around the bucket with salt water. Pour at least four gallons of salt water into the hole, filling the area between the outside of the bucket and the sides of your hole.

• 6

  Place the second polythene sheet over the hole. Spread it over the entire hole and hold the four corners in place, leaving a slight bit of slack, with stakes.

• 7

  Place the weight in the center of the polythene sheet (over the center of the bucket), lightly pulling down on the sheet to create an incline toward the center.

• 8

  Allow the system to sit in the sun for the entire day. As the heat increases inside the pit, water will evaporate, condense on the top polythene sheet, roll down the incline toward the center and drop into the bucket, having left minerals and salt behind in the pit.

• 9

  Remove the polythene sheet and empty the bucket of fresh water into a drinking container.