Reverse Osmosis Plants use the principal of "osmosis" to produce high-quality purity water.

Reverse Osmosis is a process which forces a highly concentrated stream of dissolved salts through a semi-permeable membrane into two separate streams:

a) A stream of purified water, known as permeate;

and

b) A stream of the removed highly-concentrated dissolved solids, known as concentrate or reject.

Water pressure at typical pressure of 200 to 400 psi reverses the natural osmotic tendency of the solution, hence the term "reverse osmosis".