Desalination

( Article Type: Explanation )

Desalination describes the process of removing dissolved salts from salt water or brackish (slightly salty) water to make it fit for consumption by humans or for use for agricultural and other human activities. Common types of desalination include distillation and reverse osmosis.

Distillation involves the use of energy to condense the liquids and cool them rapidly to convert them into water condensate. Reverse osmosis is a process using membranes or thin ‘skins’ through which water will pass, leaving the salts behind.

Some countries in the Middle East have now established desalination plants in order to produce fresh water for human consumption because of the desperate shortage of fresh water. There are about 7 500 desalination plants in 120 countries, which provide about 0.1% of all fresh water used by humankind.

South Africa is fast running out of potential new sources of water and desalination is likely to become one of the options to be considered in order to augment the country’s current water supplies after 2015. The high costs related to desalination means that it only becomes a feasible option when most other practical options such as reduction, recycling, or re-use, are exhausted, and when the high costs are no longer such a significant factor in the decision-making process.