The cheapest option to purify water, is to evaporate it – this will remove salts and contaminants. But adding heat is expensive. High school physics gave you the answer.
1M of vacuum head will cause even ice to form pure water vapour – it will boil off. Leaving all salts and contaminants behind.
So this will convert sea or river water, into pure water. And by definition we are only talking about 1 atmosphere. Not the 8 for high pressure desalination – which is dangerous, and requires constant filter change.
Any leak, and somebody loses a limb or their life. 1 W can easily be produced by 1/10th of a square meter of solar panel in the hot countries. A small wind turbine will power a small hamlet, and produce all their fresh water.
In Saudi Arabia, water is dearer than oil! But for the price of a solar panel from India, they can produce the fresh water for 20 houses.
What we actually do, is have a chain of solar pumps, to transfer the water vapour into the centre of the country. And re-establish the lush arable area that use to feed Rome in 0 AD.
The plants suck CO2 from the air-even today photosynthesis on the land and seas reduces average CO2 around the Earth to a pre-industrial 2 parts per million. Mankind's CO2 adds 10 seconds to the growing day of plants.
No reputable scientist would ever propose that burning the fossil fuels did more than increase active life on Earth: it certainly CAN'T increase CO2 levels.
That is a silly lie from nuclear power, to terrify the science stupid. Which include university lecturers – who should not be in education at all.
After Fukishima each operating uranium nuclear plant needs insurance of 100 billion – not commercially available. So ever nuclear plant on Earth must shut down.
A steam plasma tube does H fission
1 H2O+TU->E3+L+X-ray E3=2.5 MW for each 50x1cm steam plasma tube.
No life enhancing CO2, and no hyper toxic radioactive waste. So this creates the power for 800 home power users, from regular water.
Every medium business wants 2 1m tubes – producing 10 MW of heat, and 1 MW of power. The national grid will pay 3000 UK pounds per kW year. So 30 million for the unwanted power at night.
Only 28 million for the power during the day: why bother doing anything else: just do Molecular Nuclear Fusion, and watch the carbon free pounds role in.
We use the electrics from a fluorescent light to start the plasma, which self sustains a 4 bar. Using 10-17cc or regular water, for the 50x1cm steam plasma tube.
In contrast, burning Fossil Fuels only yields 45 kW/n – though it releases X-rays and light as we do Molecular Nuclear Fusion.
We can double the energy release from burning Fossil Fuels, by Ti plating the boiler plate or inside of the engine.
But the steam plasma takes one jolt of power to start off, and self sustains at 4 atmospheres. Utilising a minuscule volume of regular water.
Why burn oil and gas?
A 25x1cm steam plasma tube will generate 60 kW of power – enough to run a medium sized helicopter at near supersonic speed.
Injecting water drops into a jet exhaust, will increase the thrust by over an order of 10. Reducing the carbon footprint of air travel by the same amount. But again, cO2 is at pre-industrial levels – and only increases life on Earth.