Distilled water is different from the spring and purified water available in grocery stores. It is produced by evaporating water vapor from a water source (brackish water, seawater or even urine) and condensing the vapors. Properly distilled water is free of pathogens (harmful organisms), colloidal metals or dissolved organics.
Home water distillation is a straightforward process using commercially available systems or homemade systems. It is also a practical, "green" technique using a solar still and sunlight.
Stove-top water distillation
Begin with a one-gallon or larger stock pot that has a top-handle lid.
Replace the top handle (unscrew the handle from the lid) with a brass barbed fitting (hollow center) of the same size as the screw that held the top handle. This will ideally be a 3/8 inch I.D. or larger barbed fitting.
Attach clean plastic (three to five inches long) or a tygon hose to the brass fitting.
Place the other end of the hose in a clean container at least two feet away from the stove-top and slightly below the height of the lid when it is on the pot.
Add water to the pot and heat it on the stove, bringing it to a low boil with the lid still off. This is cooking off any volatile chemicals in the water before distillation.
When the water is boiling, place the lid on the pot.
Steam from the remaining water will pass through the hose, cooling and condensing as it does. The condensation will collect in the clean container as distilled water.
Stop the process before all of the water in the pot has boiled away and clean the pot, hose and collection container before starting the process again.
Simple solar distillation
The simplest method of solar distillation is to start with two clear, clean plastic bottles with screw-on tops.
Drill a hole in the source bottle lid just large enough to fit the end of a plastic hose through it. Drill a slightly (1/8 to 3/16 inch) larger hole in the lid of the collecting bottle.
Put source water (tap, brackish or even salt water) into the source bottle, screw on the lid and place it in full sunlight. Place the collecting bottle, with its lid attached, slightly lower than the source bottle but out of the direct sun.
Water vapor from the source bottle will condense in the hose and collect in the collection bottle.
Clean both bottles and the hose before repeating the process.
This is a slow method and does not produce much distilled water, but it requires no gas or electricity.
Larger scale solar water distillation
The rate of evaporation drives the quantity of distilled water produced. By building solar distillers with a larger surface area exposed to the sun, more water will be evaporated. Lining the evaporation area with black plastic, choosing a sun-facing that provides the longest sun exposure and sealing the evaporation chamber against leakage of water vapor will improve the system's efficiency. Many engineering schools and green websites have examples of efficient solar designs.
Tags: distilled water, source bottle, water distillation, barbed fitting, clean container, clean plastic, collecting bottle