What is Reverse Osmosis?
Posted on 10/04/2017 15:42:00
What is Reverse Osmosis?
To put it very simply, Reverse Osmosis (commonly referred to as RO) is a water purification process that removes ions, molecules and larger particles from water. After the purification process, you are left with pure water, no bacteria but also no minerals.
In order to understand the process more easily and its benefits, let’s look at what osmosis is; Encyclopaedia Britannica says that osmosis is the passage or diffusion of water or other solvents through a semipermeable membrane that blocks the passage of dissolved solutes…still a bit complicated?
Imagine a tank of water that has a semi-permeable membrane running through the middle of it, dividing the tank in two. This membrane is super fine and will only allow water to pass through. In one half of the tank you have a mixture of water and solutes (stuff dissolved in the water) - a solution, and in the other half you have plain old water (your solvent). Over a period of time, the water will flow from the plain side to the solution side, trying to balance up the solution on both sides, so they are equal. Water will always want to find an equilibrium and the pure water will move over the concentrated side to even things up.
This, in very simple terms, is osmosis. Reverse Osmosis is simply reversing this process by making the solvent filter out from the higher concentrate, to the lower concentrate solution. So instead of balancing the solutions, you end up with one side of the tank that is highly concentrated and leaving the pure water on the other side. Reverse osmosis needs pressure to work.
Reverse osmosis can remove many types of dissolved and suspended items from water, including bacteria, and is used in both industrial processes and residential applications.
Who wants reverse osmosis water?
RO household drinking water purification systems are commonly used for improving water for drinking and cooking, where its important to rid the water of particles and bacteria. Households with private water supplies, where the water might come from a well or a bore hole, will typically install an RO system to ensure their water is pure enough to drink and use.
RO systems are vital for those people who have low immunity (though illness) and need to ensure their water supply is as pure as it can be.
Many households have a need to have purer cleaner drinking water. This maybe to remove certain elements from their water supply, for example, high natural fluorination occurring in water can lead to enamel fluorosis (mottled teeth).
These household systems have a number of steps or processes, including sediment filters of different pore sizes, to trap particles; an activated carbon filter to trap organic chemicals and an RO filter which is a thin film composite membrane. Additionally an ultra-violet lamp can be used for disinfection of any microbes that may escape filtering by the RO membrane.
Many businesses, especially in the food production industry need to have RO water in order to guarantee the purity of their product and maintain standards.
Dentists and doctors use RO systems to ensure their sterilising equipment works to the highest of standards. Tap water causes problems for their autoclave equipment due to impurities.
On a large scale, one application is to de-salinate salt water. There are now over 100 countries that have large scale desalination plants (RO plants) to remove the salt from seawater in order to make it drinkable.
It's also used for recycling purposes; the chemicals used to treat metals for recycling creates harmful wastewater, and reverse osmosis can pull clean water out for better chemical disposal. But even more fun than recycling? Wastewater reverse-osmosis treatments, wherein wastewater goes through the process to create something drinkable. They've nicknamed it "toilet to tap" for a reason but what an incredible way for developing nations to produce drinkable water!