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Last week I gave the example that if ten full glasses represented all the water on Earth, the fresh water portion would only be about one-third of one of the glasses. And keep in mind we share that with every living thing from bacteria to sequoia trees, plus a good portion of the fresh water we have is frozen at the poles or cruising around in icebergs or flowing along in glaciers. In countries that receive little rain like Sub-Sharan Africa or in states like Nevada or in Southern California, which are really desserts with loads more people than the local water supply can accommodate, at some point the taps will run dry unless a way is found to make fresh water.
Nature does it for us by evaporating water from the oceans. The water vapor goes up the salt stays behind, and eventually the water vapor turns to clouds and fresh water fall from the sky, free.
That worked pretty well until there were too many of us using billions of gallons of fresh water for watering golf courses, lawns, filling swimming pools and billions and billions of gallons a day making stuff, like cars and ironically water bottles.
So what do we do now that we are literally running out of fresh water? Well, we can make fresh water out of sea water just like nature does, but the catch is that it is expensive. Right now the Middle East and Saudi Arabia make up to 70 % of their fresh water from sea water, but then the Saudi’s have plenty of money and lots of cheap oil to run the de-salting plants. (Wonder how they got so rich? A few decades ago the Saudis lived in tents barely making ends meet selling stuff to tourists on the way to Mecca.)
Anyway, there are two main ways water is de-salted---by evaporation or by a process called reverse-osmosis.
The evaporation method is pretty straight forward, you heat sea water, collect the water vapor, cool it and you have liquid fresh water and a really salty brine to get rid of, probably by dumping it back into the ocean, hopefully not on marine organisms that will be injured by high salt concentrations.
The other way is reverse osmosis which is pretty simple too. Basically you have a tank divided by a membrane, a membrane in this case is something that lets water through but not salt, put about 1200 pounds per square inch on the side with the salt water and collect the de-salted water on the other side of the membrane. That requires pumps to provide the pressure and they use energy.
Both methods are expensive, but if you or your industries are thirsty enough you’ll pay what you have to pay.
As of today there are 1200 de-salting plants in the United States with more in the planning stages. What water makers would really like to do is hook up de-salting plants with Nuclear Reactors to supply power. But, the problem here is, that safe as they claim the plants may be, nobody can agree where to store the thousands of tons of radioactive waste for thousands of years.
Not in my backyard, dude.
Nature does it for us by evaporating water from the oceans. The water vapor goes up the salt stays behind, and eventually the water vapor turns to clouds and fresh water fall from the sky, free.
That worked pretty well until there were too many of us using billions of gallons of fresh water for watering golf courses, lawns, filling swimming pools and billions and billions of gallons a day making stuff, like cars and ironically water bottles.
So what do we do now that we are literally running out of fresh water? Well, we can make fresh water out of sea water just like nature does, but the catch is that it is expensive. Right now the Middle East and Saudi Arabia make up to 70 % of their fresh water from sea water, but then the Saudi’s have plenty of money and lots of cheap oil to run the de-salting plants. (Wonder how they got so rich? A few decades ago the Saudis lived in tents barely making ends meet selling stuff to tourists on the way to Mecca.)
Anyway, there are two main ways water is de-salted---by evaporation or by a process called reverse-osmosis.
The evaporation method is pretty straight forward, you heat sea water, collect the water vapor, cool it and you have liquid fresh water and a really salty brine to get rid of, probably by dumping it back into the ocean, hopefully not on marine organisms that will be injured by high salt concentrations.
The other way is reverse osmosis which is pretty simple too. Basically you have a tank divided by a membrane, a membrane in this case is something that lets water through but not salt, put about 1200 pounds per square inch on the side with the salt water and collect the de-salted water on the other side of the membrane. That requires pumps to provide the pressure and they use energy.
Both methods are expensive, but if you or your industries are thirsty enough you’ll pay what you have to pay.
As of today there are 1200 de-salting plants in the United States with more in the planning stages. What water makers would really like to do is hook up de-salting plants with Nuclear Reactors to supply power. But, the problem here is, that safe as they claim the plants may be, nobody can agree where to store the thousands of tons of radioactive waste for thousands of years.
Not in my backyard, dude.
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