What processes are available to convert salt water into fresh/drinkable water?”
Distillation – this involves heating the water to a vapor. This will leave the minerals behind. The vapor can be captures and condensed in a clean environment where it will be almost completely pure. There are many different ways to heat the water, and it is very energy intensive. Ion exchange uses non-soluable ions to capture the soluble ions in the water. First the positive ions are attracted to the non-soluble negative ions, and then can be filtered out. Then the negative ions are attracted to the non-soluble positive ions and filtered out. This is similar to home water softeners. Membrane processes use a semipermiable membrane that allows water to flow through it, but prevents contaminants from flowing through it. One way is called reverse osmosis, where water under pressure is forces through the membrane. The membrane must be constantly cleaned to prevent buildup of the contaminants and slowing the flow. There are different membranes and different pressures used in different types
