Question

what is the natural technique of obtaining distilled water from the nature

Answer 1

Until World War II, distilling sea water to produce fresh water was time-consuming and expensive in fuel. The saying was: "It takes one gallon of fuel to make one gallon of fresh water." Shortly before the war, Dr. R.V. Kleinschmidt developed a compression still, which became known as the Kleinschmidt Still, for extracting fresh water from sea water or contaminated water. By compressing the steam produced by boiling water, 175 gallons of fresh water could be extracted from sea water for every gallon of fuel used. During World War II this equipment became standard on Allied ships and on trailer mounts for armies. This method was in widespread use in ships and portable water distilling units during the latter half of the century. Modern vessels now use flash-type evaporators to boil sea water, heating the water to between 70-80 °C and evaporating the water in a vacuum; this is then collected as condensation before being stored.

Solar stills can be relatively simple to design and build, with very cheap materials.