How to Use Solar Energy to Purify Polluted Water or Saltwater

Solar evaporation purification (or solar desalination) is a process that is often used to make contaminated or saltwater drinkable. It uses only the sun's energy to generate clean, potable water. Solar desalination plants have been installed in areas that are commonly plagued with potable water shortages, like Australia and the Middle East, but you can use this technology to make a small solar desalination unit in your own back yard. Unlike other filtration methods, solar desalination does not require expensive equipment or replacement parts, making it an easy and environmentally friendly choice for water purification.

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You can purfiy water through evaporation and condensation.

Step 1

Glue the 1 lb. weight to the base of your glass jar. The weight will be submerged in water, so make sure that you are using nontoxic, waterproof glue that is strong enough to hold both the weight and the glass jar. If possible, find a cylindrical weight that fits the base of your glass jar.

Step 2

Place the glass jar (with weight attached) inside your 5-gallon bucket. The jar should be centered on the floor of the bucket, a few inches below the rim and should allow room for the bucket to fill with water.

Step 3

Fill the space around the jar with contaminated water or saltwater. Make sure you are not putting any water inside the glass jar; rather, between the outside of the jar and the walls of the bucket. Imagine a moat around your jar.

The weight should hold the jar in place.

Step 4

Cover the top opening of the bucket with transparent plastic sheeting. Make sure your piece of sheeting is large enough to fully cover the bucket's opening without leaving any spaces through which water vapor could escape.

Step 5

Secure the sheeting by looping masking tape around the rims of the bucket. The sheeting should be tight, with only a slight bit of give.

Step 6

Place the 1/8 lb. weight in the middle of the plastic sheeting over your bucket. The weight should slightly curve the plastic sheeting downward toward the center.

Step 7

Leave your bucket in an open area that gets a good amount of sunlight. Solar energy will evaporate the water, which will then condense on the plastic sheeting, roll down the curve created by the 1/8 lb. weight, and drop into the glass jar, leaving salt and solid contaminants in the bottom of the 5-gallon bucket.