For Texas: If Texas is running out of water, why can't we filter the Ocean Salt Water and run a pipeline?

Question

There is a pipeline for oil in Alaska, why not a pipeline from the southern ocean in Texas to run water through out and filter out the salt, I hear France does it, don't know if that is true. But surely we can come up with the technology to do so, we can after all spend money to goto the moon.

Answer 1

You can't remove dissolved solids from solutions by filtration. You either have to distill the solvent and recover it or remove the solute by ion-exchange. Both of these are extremely expensive and energy intensive.

Answer 2

France does not do that. Saudi Arabia does though. An ordinary filter will just let the salt through, so you need to use reverse osmosis, which is basically a filter with REALLY small holes. But massive pressure is needed to force the sea water through such a filter, and the power needed to run the pumps is so high that you need really cheap power to make it worth while. The Arabs have cheap oil to power generators to run the pumps, and they also live in the desert and so are willing to pay a VERY high price for fresh water. The US and other countries do this in some special cases, but to supply the trillions of gallons of water needed by the whole state of Texas in a year would take all the electricity in the country.

Answer 3

It is being done. There are desalination plants in some part of the world where fresh water is scarce but that are close to ocean. But it takes a lot of energy. So water ends up costing quite a bit, and would prove not cost effective for things like crop growing, as the food produced would be too expensive as a result.

Answer 4

Taking salt out of ocean water is done in a few places. But it's so expensive and takes so much energy that mostly it isn't worth the money just so some Americans can live in a desert. We can just live somewhere else instead. Mostly it's done by oil rich countries in the Middle East.

This page has a lot of good information about it.

http://www.coastal.ca.gov/desalrpt/dchap1.html

Answer 5

As many people pointed out, among existing filtration technologies only Reverse Osmosis is feasible and financially viable to do that. But it will be expensive and will consume lots of power.

Large-scale projects like that will consume lots of money and resources. But it can be started on a small scale. Currently, there are a number of projects going on in Africa, Middle East, Spain, even Mexico. Japanese have advanced RO membrane technologies as well.

Izrael's Ashkelon Water Desalination plant is one of the largest in the world, and produces about 13% of Israel's water needs. Calculate roughly - 6.2 million people in Israel * 13% ~ 800,000 people use water from it. At about 21 million, you would need 26 plants like that to provide water to the whole state of Texas. Cost of Israel's plant is $250 million, so we are talking about $10 billion dollar investment in water filtration - a little steep for the state of Texas.

But I would start on a smaller scale first - like a small town of under 100,000.

Answer 6

Farming does use a lot of water but we do little in the cities to reduce water consumption. With population in the cities growing, water management makes more sense. Australia, being the driest continent on this planet, has been implementing water magagement for decades. If we take actions and implement something halfway the australians does, we would significantly reduce the water demand and conserve our water resources. A very high percentage of drinking water is also wasted daily through leaks in our water distribution system.

Answer 7

Filtering salt water to make freshwater can be done through reverse osmosis, but it is expensive and takes a lot of energy. It isn't really feasible to do this on a large scale at this point.

Answer 8

Who says Texas is running out of water, but yes, sea water can be desalinated, it is done in many locations where there are not other sources of fresh water.

Answer 9

It is called desalination. And they do it Kuwait.

The cost is somewhat high. But if that is the only alternative and you can afford it, then it can be done.

Answer 10

It could conceivably be done, but not in a cost effective way. Actually, if we would just quit wasting water (e.g. irrigating cotton on the Caprock) there would be enough.