What Is Reverse Osmosis And How Does It Improve Your Water?

Reverse Osmosis, we know it for purifying our water, but how does it work? When I hear osmosis, I think Osmosis Jones, the blue cartoon figure who plays out his existence as a crime fighting cop in the body of Bill Murray. But that image is a far stretch when looking at a glass of purified water and wondering how it got that way.


To start off, let’s understand osmosis, and then look at reverse osmosis and how it happens.


Osmosis is the diffusion of water through a selectively permeable membrane.This allows only water molecules to pass through, leaving behind the solutes including salt and other contaminants.

To put it in simpler terms, imagine you have a concentrate of Juice that needs to be watered down. There is a separation between the two liquids that allows the water to flow into the juice, but not the juice to flow into the water. As the water flows into the concentrate of Juice, the juice becomes diluted, and this is known as Osmosis.

Reverse Osmosis

Reverse Osmosis a process by which a solvent passes through a porous membrane in the direction opposite to that for natural osmosis when subjected to a hydrostatic pressure greater than the osmotic pressure.

Not all examples are as appealing as the juice example. Often we have concentrates of less appealing liquids that need to be filtered into clean water. For this we use Reverse Osmosis. It’s the opposite of osmosis. So take our juice example again and imagine we diluted our juice too much and now it’s too watery. We don’t have any more concentrate to add, so we need to take some of the water out.

The separation between the two liquids allows for water to pass through, and since the water and juice are mixed together, the water doesn’t want to flow back through. In order to get the water back on it’s original side, we need to push it through, adding pressure so it will let go of the juice, and pass through the holes just big enough for water to fit through.

Applying this pressure on a concentrate and pushing it through a semipermeable membrane (the separator) to get only water is called Reverse Osmosis.

Semipermeable Membrane

Wow, what a mouthful! It sounds like a brain devouring mutant from a zombie apocalypse comic. Thankfully we still have our juice analogy to refer back to. It’s the separator between the two liquids. A filter that only allows water to get through.

So what’s with the big name? Well, it’s no ordinary task filtering only clean water and with such a big role comes the big title. When you think about the microscopic level of a water molecule, you can start to get a sense that there is some real science behind this seemingly simple piece of the puzzle. Semipermeable Membrane works for me.

What Substances are Removed?

A very high pressure is required to push water through the semipermeable membrane. But what doesn’t get pushed through?
Things like: Irons & Metals, Particles, Pesticides, and even Radionuclides. The semi-permeable membrane leaves 99% of dissolved salts behind in the reject stream.

What are the Applications?

This quality of filtration allows for the highest quality of applications. Reverse Osmosis is used in the Power Generation, Pharmaceutical, Food & Beverage, Semi-Conductor, and Metal Finishing Industries.

That’s some high quality H2O!