Cytolysis, or osmotic lysis, occurs when a cell bursts due to an osmotic imbalance that has caused excess water to move into the cell.

The osmotic pressure of ocean water is about 27 atm.

Similarly, the properties of water mean that tissues must have certain osmotic properties in order to function properly.

The reverse process, cytolysis, can occur if the cell is in a hypotonic solution resulting in a lower external osmotic pressure and a net flow of water into the cell.

This pressure, turgidity, is caused by the osmotic flow of water from an area of low solute concentration outside of the cell into the cell's vacuole, which has a higher solute concentration.

The water to be purified is placed in a chamber and put under an amount of pressure greater than the osmotic pressure exerted by the water and the solutes dissolved in it.

In contrast, this phenomenon is not observed in animal cells which have no cell walls to prevent them from being burst by the flow of water into the cell and must either continually pump out water, with a contractile vacuole, or live in an isotonic solution where there is no osmotic pressure.