What makes it difficult to make drinking water from sea water by using evoporation?

Question

What makes it difficult to make drinking water from sea water by using evoporation?

Answer 1

A couple of factors work against relying on evaporation to produce drinkable water: economics, time and space.

On average it costs about $200 to move an acre foot of water (around 326,000 gallons) into a water supply system.  This cost skyrockets to $1,000 to move desalinated seawater into a comparable water supply system.  This is using a heat driven process that is much more efficient than evaporation (see first link below).

It's estimated that to produce fresh water from salt water via evaporation on a level that could service even a small community would cost over $3,000 per acre foot.

Even if you had a number of retaining ponds and water collection panels, only around 1,200 gallons of "moderately" desalinated water could be produced over 24 hours.

Which now goes to the area needed to provide an acceptable amount of fresh water via evaporation.  Retaining ponds and collection panels wouldn't need to be measured in feet available, but miles!

Answer 2

Necessity is the mother of invention!!!!!! This may be option left.

Answer 3

its cost really consumes all the money we have.

Answer 4

energy costs.  The sun evaporates sea water, of course, but to speed up the process, you heat the sea water, which takes lots of energy.  Additional energy is expended condensing the water vapor to collect the desalinized water.

Answer 5

you make salt from sea water by evaporation.

sea water is not just salt

it has a collection of other elements

and it is very expensive to get drinking water from sea water

The whole world would have been doing it by now if it was easy

Answer 6

it's a smart idea, but all our rich governments care about is money, something that would be wasted by this

they're just too cheap

Answer 7

this question doesn't really make much sense. If you drink sea water you will get sick becuz of all the salt. If you let the water evaporate salt is all that will be left.

Answer 8

time

Answer 9

the main cost is energy so it is easyer to just use fresh water more efficiently.

that's what they used to do with desal. then they moved on to membranes which use less power and now they are moving onto vacuum freezing which will use even less power.

Answer 10

Corporations make it difficult - not enough profit margin.....

Come on, this can be done, and cheaply too.  Hello?? Solar engery to HEAT the water to Steam!! Then reclaim the steam to condense into water.  EURKEA!!  If i was only as dumb as a scienctist.....

Answer 11

You can make drinking water from salt water but herein lies the problem - it is too expensive.

To answer your question, if you use evaporation, all you will have left is salt not water.

Answer 12

It is not particularly difficult and has been done in many different places.  Many years ago, the standard Air Force survival pack contained an inflatable solar still that produced drinking water from sea water by evaporation and recondensation.  Falling film evaporation has also been used in commercial scale desalination facilities, though reverse osmosis has proven to be more economical.