The Times Australia
The Times Magazine

.

The Science Behind Reverse Osmosis and Why It Matters



What is reverse osmosis?

Reverse osmosis (RO) is a water purification process that removes contaminants by forcing water through a semi-permeable membrane. This membrane allows only water molecules to pass through while blocking impurities such as salts, bacteria, and chemicals.

In simple terms, reverse osmosis works by applying pressure to push water from a more concentrated solution (contaminated water) through the membrane to a less concentrated solution (purified water), effectively reversing the natural process of osmosis.

Water treatment plant hire services specialise in reverse osmosis. The result is clean, safe drinking water with significantly reduced levels of dissolved solids and pollutants.

What is the origin of reverse osmosis?

While the phenomenon of osmosis has been understood since the 18th century, reverse osmosis as a practical water purification method was developed in the 1950s, with breakthroughs in membrane technology making it viable for large-scale use. Today, it's widely used in both residential and industrial water treatment systems around the world.

Timeline:

1748: French physicist Jean-Antoine Nollet observes natural osmosis using a pig bladder to separate water and alcohol.

1950s: Researchers at the University of California, Los Angeles (UCLA) begin investigating synthetic membranes to desalinate seawater, leading to the first practical applications of reverse osmosis.

1959: Dr. Sidney Loeb and Dr. Srinivasa Sourirajan develop the first semi-permeable membrane capable of effectively desalinating water, marking the birth of modern reverse osmosis.

1960s–70s: Reverse osmosis technology advances rapidly and begins to be used commercially for brackish and seawater desalination.

How Reverse Osmosis Works: Step-by-Step Process

Step 1: Pre-filtration – removes sediment and chlorine

The pre-filtration stage is the first step in a reverse osmosis (RO) system. Its main purpose is to protect the RO membrane by removing larger particles and contaminants that could clog or damage it.

Step 2: Pressurization – forces water through the membrane

The pressurization stage in a reverse osmosis (RO) system is the phase where pressure is applied to the pre-filtered water to push it through the semi-permeable RO membrane.

This stage overcomes natural osmotic pressure and forces water molecules through the membrane, leaving behind dissolved salts, minerals, and other impurities.

Step 3: Filtration through the membrane

The filtration through the membrane stage is the core step in the reverse osmosis (RO) process, where actual purification occurs. During this stage, RO system removes up to 99% of dissolved impurities by filtering water at the molecular level. This stage transforms pre-treated water into clean, purified water suitable for drinking and use.

Step 4: Post-filtration

The post-filtration stage is the final step in the reverse osmosis (RO) process. It ensures that the purified water leaving the RO membrane is polished for optimal taste, safety, and quality before it reaches the tap or storage tank.

What Contaminants Does Reverse Osmosis Remove?

Reverse osmosis (RO) is one of the most effective water purification methods available, capable of removing a wide range of contaminants at the molecular level. It works by forcing water through a semi-permeable membrane that blocks most impurities.

Common Contaminants Removed by RO Systems:

Dissolved Salts & Minerals

  • Sodium
  • Chloride
  • Calcium

Heavy Metals

  • Lead
  • Arsenic
  • Mercury

Chemicals & Disinfectants

  • Fluoride
  • Chlorine (usually removed during pre-filtration)
  • Chloramines

Microorganisms

  • Bacteria
  • Viruses
  • Parasites

Benefits of Reverse Osmosis

1) Removes a Wide Range of Contaminants

Effectively eliminates up to 99% of dissolved salts, heavy metals, chemicals, bacteria, viruses, and other impurities.

2) Improves Taste, Odour, and Clarity

By removing chlorine, sulfates, and organic compounds, RO enhances water's taste, smell, and appearance, making it more appealing for drinking and cooking.

3) Healthier Drinking Water

Delivers clean, low-contaminant water, especially important for people with weakened immune systems or those looking to reduce exposure to harmful substances.

4) Environmentally Friendly Alternative to Bottled Water

Reduces dependence on plastic bottles and helps lower your carbon footprint.

5) Low Maintenance and Long-Term Cost Savings

Modern RO systems are relatively easy to maintain with periodic filter changes.

6) Versatile Use

Ideal for homes, offices, aquariums, food preparation, and laboratories.

Limitations and Considerations

1) Wastes Water During Filtration

RO systems typically produce 1 to 4 litres of wastewater for every litre of purified water.

2) Removes Beneficial Minerals

Along with contaminants, RO removes essential minerals like calcium and magnesium.

3) Slower Filtration Process

Water purification through RO is not instantaneous—it takes time to pass through each stage.

4) Requires Adequate Water Pressure

RO systems need sufficient water pressure (typically 40–80 psi) to function efficiently.

5) Initial Cost and Maintenance

Higher initial installation cost compared to basic filters.

6) Not Effective Against Certain Gases or Chemicals Alone

RO membranes don’t remove dissolved gases (e.g., radon or hydrogen sulfide) effectively.

7) Sensitive to Chlorine

The thin-film composite (TFC) membrane used in most RO systems can be damaged by chlorine.

Why Reverse Osmosis Matters Today

In an era of increasing environmental concerns, aging infrastructure, and chemical contamination, reverse osmosis (RO) has become more relevant than ever as a trusted solution for safe, clean, and reliable drinking water.

  • Rising Water Contamination Levels
  • Declining Trust in Tap Water
  • Eco-Friendly Alternative to Bottled Water
  • Protection for Vulnerable Populations
  • A Solution for Global Water Scarcity
  • Improved Quality of Life

Is Reverse Osmosis Right for You?

With the help of water treatment systems in Australia, reverse osmosis (RO) is a powerful water filtration method, but it’s not one-size-fits-all. Whether it’s right for you depends on your water quality, health needs, lifestyle, and budget.

RO May Be Right for You If:

  1. You Have Poor Water Quality
  2. You Want Safer Drinking Water
  3. You’re Spending Too Much on Bottled Water
  4. You Cook and Brew Beverages Often
  5. You Live in a Hard Water Area

RO May Not Be Ideal If:

  1. You Have Low Water Pressure
  2. You Need High Flow Rates
  3. You Prefer Mineral-Rich Water
  4. You’re Concerned About Water Waste

Times Magazine

Building an AI-First Culture in Your Company

AI isn't just something to think about anymore - it's becoming part of how we live and work, whether we like it or not. At the office, it definitely helps us move faster. But here's the thing: just using tools like ChatGPT or plugging AI into your wo...

Data Management Isn't Just About Tech—Here’s Why It’s a Human Problem Too

Photo by Kevin Kuby Manuel O. Diaz Jr.We live in a world drowning in data. Every click, swipe, medical scan, and financial transaction generates information, so much that managing it all has become one of the biggest challenges of our digital age. Bu...

Headless CMS in Digital Twins and 3D Product Experiences

Image by freepik As the metaverse becomes more advanced and accessible, it's clear that multiple sectors will use digital twins and 3D product experiences to visualize, connect, and streamline efforts better. A digital twin is a virtual replica of ...

The Decline of Hyper-Casual: How Mid-Core Mobile Games Took Over in 2025

In recent years, the mobile gaming landscape has undergone a significant transformation, with mid-core mobile games emerging as the dominant force in app stores by 2025. This shift is underpinned by changing user habits and evolving monetization tr...

Understanding ITIL 4 and PRINCE2 Project Management Synergy

Key Highlights ITIL 4 focuses on IT service management, emphasising continual improvement and value creation through modern digital transformation approaches. PRINCE2 project management supports systematic planning and execution of projects wit...

What AI Adoption Means for the Future of Workplace Risk Management

Image by freepik As industrial operations become more complex and fast-paced, the risks faced by workers and employers alike continue to grow. Traditional safety models—reliant on manual oversight, reactive investigations, and standardised checklist...

The Times Features

Is our mental health determined by where we live – or is it the other way round? New research sheds more light

Ever felt like where you live is having an impact on your mental health? Turns out, you’re not imagining things. Our new analysis[1] of eight years of data from the New Zeal...

Going Off the Beaten Path? Here's How to Power Up Without the Grid

There’s something incredibly freeing about heading off the beaten path. No traffic, no crowded campsites, no glowing screens in every direction — just you, the landscape, and the...

West HQ is bringing in a season of culinary celebration this July

Western Sydney’s leading entertainment and lifestyle precinct is bringing the fire this July and not just in the kitchen. From $29 lobster feasts and award-winning Asian banque...

What Endo Took and What It Gave Me

From pain to purpose: how one woman turned endometriosis into a movement After years of misdiagnosis, hormone chaos, and major surgery, Jo Barry was done being dismissed. What beg...

Why Parents Must Break the Silence on Money and Start Teaching Financial Skills at Home

Australia’s financial literacy rates are in decline, and our kids are paying the price. Certified Money Coach and Financial Educator Sandra McGuire, who has over 20 years’ exp...

Australia’s Grill’d Transforms Operations with Qlik

Boosting Burgers and Business Clean, connected data powers real-time insights, smarter staffing, and standout customer experiences Sydney, Australia, 14 July 2025 – Qlik®, a g...