How does Reverse Osmosis or RO water purifier work?

Most of us use Reverse Osmosis or RO water purifier at home. But do we know how does it works? The objective of this write-up is to explain the basic functionality of your RO in a very simple way.

RO stands for Reverse Osmosis which simply means that it is the opposite of a process called Osmosis. So let’s first understand the Osmosis Process.

What is Osmosis?

There is a natural tendency of fluids or solvents to pass from a lower concentrated solution to a higher concentrated solution through a semipermeable membrane or film. Semipermeable membrane is a film that allows only the fluid or solvent to pass but not the salts and impurities dissolved in it.

In the below diagram, fresh water has lower salt concentration compared to the salty water on the other side of the membrane. And therefore fresh water flows towards salt water (i.e. from lower concentration towards higher concentration)

The simplest example is the passage of water from soil (soil has a higher concentration of rich salts and minerals) to the roots of plant.

What is RO (Reverse Osmosis?)

RO (Reverse Osmosis) is just the opposite of the above process. Osmosis occurs naturally without requirement of any energy from an external source. But in reverse osmosis (RO) pressure is applied to the higher concentrated solution. This energy or pressure should be higher than the natural osmotic pressure. Because of this pressure, salt water moves towards the fresh water through the semipermeable membrane, leaving behind the impurities, bacteria and ions.

Inside our RO (Reverse Osmosis) firstly the water from the supply or tap (called the feed water) enters the pre-filter where the filter cartridges remove the initial dirt and sand. Then with the help of a pump this filtered water (which still has lots of impurities and salts) is made to pass through the semi-permeable RO membrane. This semipermeable membrane allows only the water to pass through it leaving almost all the dissolved salt, impurities and bacteria behind called the reject Stream. The amount of pressure required depends on the salt concentration of the feed water. Higher is the concentration of feed water, higher is the pressure required to overcome the osmotic pressure. The water coming out of the RO membrane is called Desalinated water. This water is free from almost all impurities. And finally this RO filtered water is passed through the post filters or the carbon filters which remove any remaining odour or taste from the water. Now your water is purified and ready to drink.

You need to get your RO service done in every three months, which includes cleaning or change of filters and membrane along with the cleaning of water storage tank. If your Reverse Osmosis or RO water purifier is not working or you need help with RO repair and maintenance, RO filter change, RO membrane change in Delhi and NCR, MrRight.in will find you the best RO maintenance companies in Delhi NCR, Noida, Gurgaon. 

Home repair was never this easy. 

Mr Right – Making India Smarter