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What is a Reverse Osmosis Water Filter (and Do You Need One)?

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Reverse Osmosis (RO) water filtration systems are becoming increasingly popular in Australia, and for good reason. Often considered the most effective filtration method, reverse osmosis systems offer clean, safe, great-tasting water without costing the Earth. 

There are RO systems available to suit most budgets, regardless of the water type in your area, and they are popular with both homeowners and business owners. If you’re thinking about installing a reverse osmosis system, keep reading to find out what they are, what they do and why they’re so useful.

What is Reverse Osmosis? 

Reverse osmosis filtration systems use pressure to force water through a series of filters, removing up to 99% of contaminants, including unwanted bacteria, minerals, chemical substances and other impurities.

The number of filtering stages varies depending on the system, but will almost always consist of prefilters and postfilters, all of which are purpose-designed to remove specific contaminants. The reverse osmosis process occurs during the postfilter stage, when water is forced through a semipermeable membrane that blocks contaminants and dissolved solids but allows water molecules to pass through.

During this process, pressure forces the water to travel from the concentrated (contaminated) side, through the membrane, to the less concentrated side. The fresh water it produces is called permeate, while the wastewater it leaves behind is known as brine. Depending on the filtration system, there may be  additional specialty post filtration stages, as well as drainage and water storage. 

To better understand reverse osmosis, let’s look at regular osmosis. You might remember this from school science lessons. During osmosis, water passes through a membrane, but instead of leaving behind contaminants, it creates an equal level of concentration on both sides. Reverse osmosis, however, blocks those contaminants from getting to the less concentrated side of the membrane, which is how the clean, fresh water is produced. 

Stages of Reverse Osmosis 

The design of reverse osmosis systems may vary depending on the brand, but generally they follow the same process: pre-filtration, reverse osmosis, specialty filtration, drainage and storage. Let’s take a look at those stages in more detail. 

Stage 1: Pre-Filtration

Once connected to your drinking water lines, a high pressure pump forces water through a series of pre-filters to remove sediment. Here at Complete Home Filtration, water passes first through a 1 micron poly-propylene sediment filter designed to remove sediment, silts and mineral deposits. 

Stage 2: Activated Carbon

If you install a reverse osmosis system from Complete Home Filtration, we add in a micron activated carbon block. This stage removes pesticides, herbicides, chlorine (and chlorine by-products) and volatile organic compounds (VOC’s) to protect the membrane.

Stage 3: Reverse Osmosis

This is where the magic happens. During the reverse osmosis stage, water is forced through an incredibly tightly woven, semipermeable membrane. To the naked eye, the membrane may look impermeable, but in reality, with enough pressure, water can pass through. This filters the water from 1 micron to 0.0005 microns, removing impurities like fluoride, lead, cadmium, hormones, pharmaceuticals and more.

Steps 4: Specialty Filtration

Following the reverse osmosis stage, some systems add in a speciality filtration stage. This is designed to remove any contaminants that got through the RO stage, like mercury, volatile organic compounds (VOCs) or lead. 

Stage 5: Remineralisation

If you install a reverse osmosis system from Complete Home Filtration, we also add in a remineralisation stage. This is designed to add trace elements of calcium, magnesium, potassium and mineral salts to restore a PH of 8.4, which is vital for retaining beneficial levels of minerals in your drinking water. 

Step 6: Drainage and Storage

Once the reverse osmosis system has drained the waste water, the treated water is stored in the RO tank ready for later use. 

How Is Reverse Osmosis Different From Standard Filtration? 

Reverse osmosis systems differ from other filtration systems by the number of filters the water passes through. With high levels of water pressure and the highly concentrated, semipermeable membrane, reverse osmosis is a much more thorough process.

Traditional pitcher-style filtration systems use activated carbon to remove the taste and smell of chlorine. However, these aren’t as effective at removing dissolved solids or other contaminants and bacteria.

Should You Buy a Reverse Osmosis Filtration System? 

Reverse osmosis systems are the ideal way to get clean, fresh, rejuvenating water for your home if you’re looking for a highly effective filtration system.

You can avoid single-use plastic bottles and tiny bench-top filter jugs by using RO systems to protect your health, family, and home from contaminants.

To find out more about reverse osmosis filtration systems, please read our comprehensive guide. To speak directly to an informed member of our team, contact us today.