What Is Reverse Osmosis Filtration?

Reverse osmosis is a form of water filtration that works by pushing water through a microscopically small filter material.

This semi-permeable membrane has a pore size of around 0.0001 microns. An opening that is small only allows water molecules to pass through. The membrane catches (and removes) any larger molecules, including contaminants, organic materials, or even salt. Reverse Osmosis systems were originally designed to desalinate seawater and reduce high chemical contaminant materials such as heavy metals. Reverse osmosis is now one of the types of filters commonly used in homes, apartments, and condominiums.

How Does Reverse Osmosis Water Filtration Work?

Osmosis typically involves the moving molecules of a substance from a region of higher concentration to a region of lower concentration until the concentrations of that substance become equal on either side of the membrane. Reverse osmosis simply adds high pressure to force the water molecules in the unfiltered water through the membrane.

Reverse osmosis removes everything from the water; from the obvious, visual contaminants (sediment and larger organic material), down to the invisible dissolved substances in the water. Reverse osmosis is so efficient that it even removes the beneficial minerals present in water, such as calcium. This also makes the water taste differently.

Residential reverse osmosis systems must maintain certain water pressure, so most have an electric pump.

Benefits of Reverse Osmosis Water Filtration

Some of the benefits of a reverse osmosis water filtration system include:

1. Reverse Osmosis Filters Nearly All Contaminants

Reverse osmosis is considered one of the most all-around effective ways of eliminating water contaminants. Even residential-grade reverse osmosis filters can remove up to 99% of lead, asbestos, and 82 other additional contaminants. You can safely disregard boil water advisories in your community if you have a reverse osmosis unit, which is properly working.

The microscopic nature of a reverse osmosis filter membrane can filter out not only the larger contaminants most water filtration systems catch, but can actually remove dissolved substances and minerals from within the water.

2. Significantly Better for the Environment and Safer than Bottled Water

For communities for which the only other option for drinking water comes from disposable plastic bottles, reverse osmosis is a safer and marginally better option. Reverse osmosis does displace water during its filtration process. This is called its recovery rate. However, the discarded water is small compared to the cost of plastic water bottles ending up in landfills and the pollution involved in the production of plastic and transportation by trucks.

The news is full of questions regarding the quality of bottled water. The most recent discovery is the thousands of pieces of microplastics found in bottled water. One test in the UK revealed 93% of bottled water showed some sign of microplastic contamination. http://news.bbc.co.uk/2/shared/bsp/hi/pdfs/14_03_13_finalbottled.pdf. The same results were found throughout Canada.  https://www.youtube.com/watch?v=2zOBQDdE1Ys. 

3. Mineral-Less Water May Be Necessary for Certain Uses

Some chefs claim that water filtered with reverse osmosis makes their cooking taste better since it lacks the presence of minerals, including municipally-added fluoride.

Bottom Line

Reverse osmosis water filtration is certainly one of the most effective forms of water filtration available. It works best when providing fresh water in areas where safe water is scarce and for desalinating ocean water to make it potable.