Reverse osmosis is the finest filtration known. This process will allow the removal of particles as small as ions from a solution. Reverse osmosis is used to purify water and remove salts and other impurities in order to improve the color, taste or properties of the fluid. The most common use for reverse osmosis is in purifying water. It is used to produce high purity water that meets the most demanding specifications.

Reverse osmosis uses a semi-permeable membrane, allowing the water that is being purified to pass through it, while rejecting the minerals present in the water. Generally Reverse osmosis technology uses a process known as cross flow to allow the membrane to continually clean itself. As some of the water passes through the membrane the rest continues downstream, removing the rejected species away from the membrane. The process of reverse osmosis requires a driving force or a High Pressure Pump to push the water through the membrane, The higher the minerals or dissolved solids present in the water, the larger the driving force or pressure requirement.

Reverse osmosis is capable of up to 99.5 % salt rejection and being the finest membrane available it is very much prone for fouling with various contaminants such as colloids, heavy metals, oil & grease etc. RO membranes are also not able to tolerate the chlorine, therefore, while designing a RO system, precaution for avoiding all this is to be taken into consideration, therefore, in recent times Microfiltration is getting popularity a RO pretreatment solution world wide.

RO systems are also preferably PLC based so that all safety features and limiting conditions can be taken care off.