A Rough Guide to Reverse Osmosis

If you are considering water treatment technology, you are likely to have come across the term “reverse osmosis.” Known in the industry as Hyper Filtration, this technology has been around since the 1950s. It was developed as a method of desalinating seawater under U.S Government funding. Today, reverse osmosis is considered the most thorough and convenient method of water filtration.

How R.O Systems Work:A Rough Guide to Reverse Osmosis

A simple explanation for how reverse osmosis systems work is that water molecules are pushed through a semi permeable membrane that is only 0.0001-micron using water pressure. Sheets of this membrane are sandwiched and rolled up around a tube to create a spiral. This spiral wound module is a typical configuration and is available in a myriad of sizes to best process the quantity of water. Modules in domestic units are usually 2” in diameter and up to 10” long, while a module in an industrial unit can be 4” in diameter and as long as 40”.

In order for the membrane to be used, it needs to be housed in a container to maintain pressure on the surface. This pressure is needed to force the water molecules through the membrane and separate out any unwanted substances. These substances are diverted to a waste drain automatically to avoid a build up in the system.

Shorter Leaves for Higher Performance:

The key to reverse osmosis systems is the membrane, but not all membranes are the same. Manufacturers use different methods to fabricate their membranes. For example, the spiral wound configuration is comprised of “leaves” of membrane. These are individual sheets that the feed water is passed through. Some brands use fewer leaves that are larger, while some use shorter leaves. The shorter leaf design does cost more to produce, but it maintains a more uniform flux as less pressure is needed to deliver water to the ends of the leaves. This creates a highly efficient device that can not only provide safe drinking water supplies, but will have a longer life.

The Importance of Flow Rates:

Another important consideration when considering reverse osmosis systems is the flow rate. All systems are rated by their flow rate and priced accordingly. This is a measure of how many gallons of treated water the unit can produce per day. The actual flow rate will depend on the temperature and water pressure in your home. Many manufacturers appreciate this and label their systems with two numbers to help you determine the model best suited to your home. If you see a system marked 36/45 GPD, this means that the system is rated 36 gallons per day when the water pressure is at 50 psi and 45 gallons per day at 60 psi. Although the industry standard is usually set to 60 psi, this is not the case for everyone. So if you do have lower water pressure levels, you can still gain insight into the flow rate you can expect from the device.

If you are unsure about choosing a reverse osmosis system for your home, you should speak to an experienced water treatment technician. A fully WQA certified professional can help guide you through the range of options that are not only suited to your requirements, but meet the industry standards.

By Mark Williams (NicMar President Mark Williams holds degrees in Applied Science and Industrial Thermodynamics, along with Agricultural Mechanization and Systems Engineering from Ohio State University. He also holds the highest possible industry ranking, being WQA (Water Quality Association) LEVEL 6 Certified.)

Print Friendly
Nicmar Water
999 Baltimore Road York SpringsPA17372 USA 
 • 800-542-8649

Water Solution Center

Educational Center