How Does Reverse Osmosis Work

How does reverse osmosis work to filter water

It is reasonable to humor the idea of turning saltwater from the ocean into drinkable water. Well, the abundant, seemingly endless amount of sea water can definitely be useful some time or another right? At least it is certainly uplifting to think so. Just imagine that when drought strikes, how many people and other living things can be saved from the existence of this usable, drinkable amount of saltwater from the vast ocean.

But then the reality hammer hits when you take your time to think about the reason why this kind of water can’t be used in a way that could benefit in a drought. One, the salinity of the water makes it impossible to be a good water to drink at all. Two, salty water is simply not great in growing plants or help them sustain their lives. But say, if there’s a technology that can reverse the salinity and turn it into the kind of water we can drink or water the plants with, don’t you think it would be wonderful? And is that kind of technology even exist in the first place?



Now that the question have been shot, the time has come for the answer. Meet Reverse Osmosis, one of the water processing methods that make desalination or removing the amount of salt from saltwater possible. Even more so than that, reverse osmosis can also be used as a means to recycle water, a proper treatment for waste-water, even can be helpful in producing energy.

In the world we are living in now, water issues have become one of the most pressing matters as the time progresses. It even goes beyond the limit of being a global threat already, with what our climate has undergone, all these impacts on our environment. Not to mention the increasing number of population also makes the demand for water skyrocketing over the roof, it is undeniable that water will always be a crucial part of humanity’s sustainability.

And what does the reverse osmosis role come into this? How can we benefit from it? Having knowledge about how does reverse osmosis work, aside from only knowing how useful it can be, can help us in so many ways. Moving with the assumption that you already have a good grasp on the definition of the word, “reverse”, this article will explain more on how the technology really work.

Reverse osmosis processing

Starting from the most basic definition of the term can help us to delve more into this matter. So yeah, let’s start from the term “osmosis” first. Osmosis can be briefly explained as the diffusion or passage of water or other kind of solvents through some kind of semi-permeable membrane that capable of blocking the passage of any dissolved solutes in the solvents. Still confused? Well indeed it was a technical definition that most people typically don’t really understand at the first glance. However, it does not have to be necessarily so. Let’s break down on this first before we move into the more semi-technical explanation of how does reverse osmosis work.

Example time! Let’s say that you have a cup of boring old water. The plain water we can basically get anywhere. This water is the solvent. Let’s say that you want to make the water less boring. So you pour down some sugar on it, and voila! What you get now is not simply the plain old water anymore. You have now a solvent, which is the water, and the solute, which is the dissolved sugar. The final solution of those two mixtures will be the sugar water.

Is it over there? Not quite. Now, we will be moving on into the what-if situation where you want to ‘reverse’ back the water to its original solute-free state. To do this, you must first grab a U-tube. Now , before you start to jump on conclusion or even start to make a pun or any other kind of joke out of the name, no, it is not the kind of thing where you put up videos about kittens and other weird stuff. U-tube here is essentially a breaker with a u-shaped form. Right in the middle of the tube, you will find the semi-permeable membrane which is really essential in making the reverse osmosis works at all.

So the U-tube has two arms. You pour down the solvent with dissolved solute in it (in our what-if case that will be the sugar water) and at the other side of the tube, you pour another water, but this one is the clear water, the plain old water like our sugar water used to be. This is where the magic happens; when the water moves, the level of the solvent in the arm where sugar water placed will rise slowly, as the solvent moves through the membrane to make both sides equivalent in the ratio of sugar-to water. Thus, making the concentration of the solute weakens.

But wait, how does that happen and what does that even mean? Basically, water wants to find its equilibrium when it moves. So the pure water from the other sides will go on its ways to mingle with the sugary water on the other side to make both of the water concentration more equal, until the osmotic pressure, or the pressure that happens when molecules move around, is gained. That’s how osmosis works! But then it is only still about osmosis. The main question of how does reverse osmosis work have not been quite answered yet. Bear with the words a little longer as we will take the explanation into the new level; explaining how the reverse in this technology occurs.

Osmosis and Reversing the State of Water

Now that we have learned about how osmosis works, the main question about how RO really works is still left unanswered. We are going to delve deeper on that. To make reverse in this process possible at all, we need to apply pressure to the solution. Or even more precise, the solution is the one that should be put under the exposure of pressure. Pressure here is important to make osmotic pressure from the pure water to the solute-filled water happens at all. And that, my friend, is the reverse osmosis. It works in a fashion that allows water to be separated from its solute elements. Leaving the fresh water on one side, and leaving the solute elements on the other side. So, how was that? Is it a good explanation? Or do you still want to know more about this technology? Let us know in comments!

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