Types Of Reverse Osmosis Water Filtration Systems

Posted on: 30 November 2016

Reverse osmosis water filters make use of a semi-permeable barrier to filter water, blocking many contaminants and minerals that may be in the water from actually being a part of your cleaning, cooking, or drinking water. There are several different types of reverse osmosis water filtration systems, each of which provides the same function but operates slightly differently from one another. Understanding the differences between the main types of reverse osmosis water filters can help you choose the one that best fits your needs.

Thin Film Composite Membranes

Thin film composite membranes, commonly referred to as TFC membranes, are the most common type of reverse osmosis membrane, and thus can be found in the largest amount of home filtration systems, no matter the size. They are extremely efficient at blocking out minerals and other contaminants, and are also extremely resistant to bacteria growth. This helps reduce the risk of your reverse osmosis water filter from becoming scummy and producing foul tasting water, and also reduces any health risks associated with bacteria buildup in your water.

However, TFC membranes are very susceptible to damage when exposed to certain chemicals that are common in municipal water supplies, especially chlorine. This means that they must make use of a pre-filter, usually activated charcoal or carbon, to remove those chemicals before they actually filter the water. What this means for you practically is that you will have an extra filter that you will have to change regularly, driving up how much maintenance you have to do and how much it costs.

Cellulose Triacetate Membranes

Cellulose triacetate membranes (CTA membranes) are slightly different from TFC membranes, as they are less effective at blocking out minerals and contaminants within the water. This makes them extremely rare for residential use in a reverse osmosis water filter system. However, they are able to withstand a certain amount of chlorine exposure without breaking down, which means that they are able to operate without a pre-filter, reducing the amount of maintenance that you have to do is reduced, as are long run costs.

It is important to note, however, the CTA membranes are also susceptible to bacteria buildup. If this does happen, the entire membrane will have to be replaced and the system cleaned out to remove all traces of the bacteria, which ends up being more expensive than replacing an occasional pre-filter – thus why CTA membranes are so hard to find actually in use.