Is seawater drinkable?
Why can't we convert seawater into drinking water?
In fact, we can, and we do, as early as ancient Greece, people have made seawater drinkable.
This process is called desalination. Desalination is the process of removing dissolved minerals, including but not limited to salt, from seawater, brackish water, or treated wastewater. Many technologies for desalination have been developed, including reverse osmosis (RO), distillation, electrodialysis and vacuum freezing.
So why is seawater so attractive that we have to go through all these complex and expensive processes to make it safe to drink?
Seawater cannot be used as a substitute for fresh water. Seawater is rich in salt, and drinking seawater can dehydrate the human body.
In survival scenarios, desalination (pumping salt out of the water) is the only way to make seawater safe enough to drink. The simplest form of desalination is basic evaporation. Think back to a basic science lesson: You might be taught that the sun heats the surface water on the ocean, which causes evaporation. When the water evaporates, it leaves salt behind. Moist air rises, cools, forms clouds, and if enough, rains.
Why don't we do that?
But the energy costs required to implement this seemingly simple process are high.
So why don't we do more desalination to alleviate shortages and growing water conflicts?
So while desalination is growing largely in wealthier countries, it also needs to reduce costs to benefit those who are poor in money. We still have a lot of work to do to make more efficient use of our existing water, but as the world's population continues to grow and water supplies dwindle, the economic tide may soon turn to desalination.
The cost of desalination may become cheaper, but it is still too expensive for poorer countries, many of which also suffer from water scarcity.