When you go to a restaurant, you see two taps: one for ‘Drinking Water’ and the other for ‘Hand Wash’. Some may decide not to drink this ‘Drinking Water’ and instead order bottled water. Why? What’s the matter here? Why can’t we drink and wash our hands too in the same water? What is so special about bottled water that many people consider it a safer option?

When you simply look at a glass of water, you can never guess its quality. It may look clean, but in reality, it has, most likely, millions of bacteria, dirt and salt particles which are not visible to our naked eyes. Due to this, the water becomes tasteless and undrinkable. Worst, you may fall sick drinking it. Hence, most people avoid drinking water outside their homes to ensure safety, especially for children.

What makes people so sure that home water is safe and pure?

From ancient days, people have their own water purifying system – boiling water or cleaning the water through filtering or sometimes using both the methods. These methods are very effective and highly reliable.

With the quality of ground water going down every day, it is a challenging task to remove all the impurities from water. Here comes in Technology to help us overcome this problem.. There are a number of modern technology processes that claim to purify water upto 99%. The most popular among them is Reverse Osmosis, shortly called RO.

Before we understand how these ‘Reverse Osmosis’ water purifiers work, we need to study what “Osmosis” is in general.

Let us say you have a special glass which is separated into two parts. On the left hand side you pour half glass of pure water and on the right hand side you pour same amount of dirty water, in between there is a Semi permeable Membrane that allows only certain things to pass through and blocks all others – for example, a small plate with tiny holes in it. If you pour water and sand simultaneously on the plate, it will allow only the water to do down and retain the sand.  Similarly, this membrane allows only water to pass through and blocks the impurities.

Now, coming back to our special glass… If you leave it for few hours, pure water will cross the membrane and go to the side where dirty water is filled. This is called ‘Osmosis’. It seems quite odd, isn’t it?  Means, we need to break this natural osmosis process and create a reverse osmosis process. That’s exactly what a RO Water purifier does.

But how does it reverse this process?

Let us say you are holding a ball in your hands; suddenly you let it go. The ball falls down due to gravity.  But is it possible to make the ball go up, instead?  Yes – if we give some additional force on the reverse direction of gravity… This can happen when you throw or hit the ball with a bat. The same logic is applied to reverse the natural osmosis process – applying pressure on the dirty water side. Thus, water molecules on the dirty side cross the membrane and enter the pure water side. If dirt or impure particles try to sneak in, the membrane prevents them from entering in.

A RO water purifier system has the following parts:

Water inlet (dirty water or salty water from tap)

Water outlet ( for pure water)

Another water outlet ( for impure water)

Inside the RO system, there are two containers, one for pure water and the other for dirty water. Let us call them PW and DW for easy understanding. Between PW and DW there is a semi permeable membrane. Once the water inlet fills the DW portion, pressure is applied on it, creating a
reverse osmosis process. Only the pure water crosses the membrane and enters PW zone. The water is purified now and is safe to drink. All the impurities are released through the waste outlet by a slim tube.

Availability of safe drinking water has become a top priority today as very few have access to pure drinking water.  Safe drinking water is essential to humans and other life forms. Only if that is ensured, we can call ourselves a true modern society!