Water osmosis

What is osmosis / reversed osmosis

Osmosis is a natural process that is taking place at the membrane of all living cells. The cell membrane is acting like a semi permeable membrane.
This characteristic allows water to pass through a lot more easy than solluted minerals.
In a tank containing to liquids, each with different consentration of minerals, the water in the sollution with the lowest consentaration will try to dilute the more consentrated sollution. This water migration will create a significant differ in pressure between the to sollutions.
As a rule of thumb you can say that for each 100 mg/l of mineral (e.g. salt) you solve in water, the osmotic pressure will increase by approx. 1 psi (0,07 bar).
Sea water has a typical mineral consentration of 35g/l. This will give an osmotic pressure of approx. 25 bar.