This idea purifies both river and salt water. Using a low power solar powered vacuum pump. I will end global hunger and thirst. I am getting thank you messages over the internet – so I am saving lives.
We take the brown or river water, and during the day apply 1 meter of vacuum head using a solar pump. In the dark lands we use a shore based windturbine to supply the power.
Below 1 meter, even ice forms water vapour – no salts or contaminants. Pure water vapour. We will need to draw off the brine, and use a vacuum to totally dry it, to form salt crystals. To form into salt licks for animals – you can live without gold, but die without salt.
We have a chain of solar pumps to transfer this vapour to a high reservoir. When we vent the vapour to the air, it falls as water drops.
Water vapour takes 1/1000th of the pumping compared to liquid water. No high pressures like high pressure desalination. So very low cost, expense and no danger.
We can turn brown river water into drinkable water, ideal for agriculture.
For Saudi Arabia, we can turn the high desert back into lush farm land – as it was in the days of the Roman empire.
So we end global hunger and thirst – and the UN will provide the equipment free, from charitable donations.