How do you define & describe Reverse Osmosis (RO) to a layman

A Prakash Rao

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Jul 2, 2021

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Reversal of osmotic flow of water is termed as Reverse Osmosis (RO)

Osmosis or osmotic flow is a natural process wherein water flows spontaneously from a dilute solution (less salt) to a concentrated solution (more salt) in order to attain an osmotic equilibrium

However in RO, which is not a natural process, you are reversing the osmotic flow by extracting pure water from a concentrated solution or in other words forcing out water molecules from concentrated (saline) solution under pressure or through application of external pressure via pump

Therefore, simply put, RO is a non-natural (unnatural) process which requires a pump and a semi-permeable membrane in order to produce pure & potable water from saline/highly saline water

RO is an energy intensive process which means that energy is consumed during RO treatment process and hence RO is relatively costly. After all, you have pay a price for altering natural process and natural flow

Limitations of RO : (1) It is an energy intensive process - you need continuous supply of electricity to drive the pump as long as the requirement of pure water is not fulfilled ; (2) It involves maintenance issues pertaining to pump, membranes & pre-filters which result in recurring costs ; (3) It produces a reject stream which needs to be tackled or taken care of

FYI : CSMCRI-CSIR located in Bhavnagar (Gujarat state) was the first R&D institute to initiate & undertake fundamental research work on RO membrane technology in India way back in 1960 following which the first ever brackish water RO plant of 10,000 litres/day capacity, based on Cellulose acetate membranes, was designed & installed in Avania village of Porbandar district in Gujarat in the year 1962

Bottom line : (1) In Osmosis, water enters the salt solution willingly without any external pressure ; (2) In Reverse Osmosis, water comes out of the salt solution forcibly under pressure for which you need to pay some price ; (3) You need to “sweat” out in order to produce sweet RO water ; (4) Make RO a priority but not a necessity ; (5) Do not make RO a status symbol