Why not use water from the sea??

Question

I understand that very little of the world's water supply is undrinkable because it is sea water. But can't they filter out the salt so that we can drink it. We wouldn't have the problem of droughts then because could we just pump sea water into reservoirs and once it is filtered we would be able to use it!!

I know it is just a stupid question, and I am sure there is a reason why we can't use sea water but I am curious to know none-the-less.

Answer 1

What you're talking about is called Desalination.

The bottom line is, it's still rather expensive to remove the sale from seawater. As the ocean gets more polluted, those contaminates will also need to be removed, making the process even more expensive.

That said, there are already a number of coastal areas that do get at least a portion of their water supply from the ocean.

Answer 2

Salt can't be filtered because it dissolves in water. Sea water can be distilled but this is a lengthy and expensive process if done on a large scale. You also have to take into account the distance between the place that needs water and the ocean. The end result would be some pretty expensive water.

Answer 3

Desalination is possible, but you need to build the plant and pump the water to where you want it. In parts of the world where there is less rainfall you get various barriers, cost the cost may not be high by western standards, but in those places it is. therefore the wealthy would be the ones to benefit, but they have enough anyway. Many countries with low rainfall do not have a coast. It is impossible to get over this, will any country with a coast be willing to supply their neighbour with water? There are often conflicts & hostility in these parts of the world and the attitude in such circumstances to finding their neighbour is short of water is likely to be 'good'.

Answer 4

Yes their is a standard way. Evaporating tha water off leavin the salt residue and condense the water. this would use a lot of energy though. I'm sure the Royal Navy have a special kind of pump incase they get shipwrecked that allowed them to remove the salt from seawater!

Answer 5

Sea water requires masses of energy to bring it to the boil to make steam of it which is then allowed to condense back into pure water. This is not a good idea. However, it is possible to turn sea water into salt free drinking water by storing it in shallow troughs under clear glass or plastic. The sunlight will then cause the water to evaporate. It will then form droplets on the under side of the glass and if this glass has been installed with a slope to one side, the water will then be able to run off into a gully or gutter to one side and away off into a reserviour.

In UK, one of the world's most 'flooded' islands, there is no need to turn sea water into fresh water. In spite of Global Warming, we're going to go on getting masses of rain. We're surrounded by seas on all sides. Warm air coming in over the Atlantic sucks up cooler air from below, this condenses, forms clouds which then dump on us. In West Wales for example, they get an average rainfall of around 88 inches [yes, a massive eighty eight inches of rain a year]. Since about 60% of Wales is above 1,500 feet, this means a huge amount of water is run off into the rivers and streams which flow down back into the sea. A lot of this water also goes into pipes and is pumped away into England, Manchester etc.

Answer 6

Salt can't be filtered out of seawater, otherwise it would be a great idea. The salt is in solution, and it makes it undrinkable, and impossible to remove by normal means. All of the methods either require too much energy or expense to accomplish. Believe me, the world has desperately searched for a way to filter seawater for many centuries. Keep those good ideas coming!

Answer 7

Desalinisation is often done in the Gulf states where they have little or no fresh water. It requires expensive equipment which takes a lot of (expensive) power to operate.
Ships (especially cruise ships) do this too, for the passengers' demands far outweigh what they could carry in tankage and they can guarantee the quality. There's also ample power available.

Answer 8

Removing the salt from sea water is called desalination. It is a relatively expensive process, however advances are being made and desalination will likely grow in the future

Answer 9

We have kinda screwed this planet up enough without draining the oceans to quench our want or need of fresh water. It is a grand idea, but the planet can only take so much, then it will reject us good and proper like.
https://www.cia.gov/cia/publications/factbook/geos/xx.html#Intro
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Answer 10

It's expensive to desalinate water! That's why the next natural resource that we will all be paying ransom for will be fresh, clean water. It's amazing that not only 50 years ago people would laugh at you for the idea to sell bottled water. Now it's so commonplace that we don't even think about it.