Posted by Jeff Wahl on 4/6/2025 to
Thoughts on Water
Purified Drinking Water Solution
Access to clean, pure and safe drinking water is a fundamental human need, yet many rural and even some municipal communities face challenges due to water contamination. Reverse osmosis (RO) has emerged as one of the most effective water purification methods, providing high-quality drinking water by removing a broad range of contaminants. This article explores the benefits of reverse osmosis, what it treats, the system's component parts, and its valuable role in rural and municipal water applications.
What Is Reverse Osmosis (RO)?
Reverse osmosis is a water purification process that uses a semi-permeable membrane to remove contaminants from water. It works by applying pressure to water, forcing it through the membrane while leaving dissolved solids, bacteria, and other impurities behind. Production of systems is dependent on water pressure and temperature, with systems ranging from kitchen single use to entire building supply.
Key Benefits of Reverse Osmosis- High-Quality Drinking Water: RO produces exceptionally pure water by removing up to 99% of dissolved salts, particles, and microbes.
- Effective Contaminant Removal: Removes harmful substances such as nitrates, arsenic, fluoride, lead, chlorine, pesticides, and microbial contaminants.
- Improves Taste and Odor: Eliminates metallic, chemical, or musty tastes, improving the overall quality of drinking water.
- Reduces Health Risks: Provides a safer water source, especially in areas with questionable groundwater or aging municipal infrastructure.
- Low Chemical Usage: Unlike other methods, RO uses no chemicals, making it environmentally friendly.
What Reverse Osmosis Treats
Reverse osmosis systems are capable of removing or significantly reducing:
- Inorganic Compounds: Nitrates, sodium, lead, arsenic, fluoride, and sulfate
- Organic Contaminants: Pesticides, herbicides, and industrial solvents
- Biological Impurities: Bacteria, viruses, and protozoa (although pretreatment may be required)
- Dissolved Solids and Salts: Total dissolved solids (TDS) that affect taste and safety
Reverse Osmosis is a Physical Separation of Contaminants from Water
Component Parts of an RO System
A typical reverse osmosis system includes several key components:
- Pre-Filters: Protect the RO membrane by removing sediment, chlorine, and other larger particles.
- RO Membrane: The core of the system, responsible for filtering out contaminants at the molecular level. The membrane in a reverse osmosis system is a semi-permeable barrier that allows only water molecules to pass while blocking contaminants. It typically has a pore size of around 0.0001 microns with the human eye at 20/20 vision seeing to about 20 microns. At this micron level, even viruses and most bacteria cannot pass through, making it highly effective for ensuring safe drinking water.
- Post-Filters (Carbon Filters): Further improve taste and remove any residual odors.
- Storage Tank: Holds purified water for on-demand use.
- Flow Restrictor and Automatic Shut-Off Valve: Maintain optimal pressure and conserve water.
- Drain Line: Disposes of the concentrated contaminants that don't pass through the membrane.
Reverse Osmosis in Rural vs. Municipal Water Rural Applications:
Rural areas often depend on groundwater or surface water, which can be contaminated by agricultural runoff (nitrates, pesticides), septic systems, surface runoff (salts and oils) and natural contaminants (arsenic, iron, manganese)
RO systems are ideal in these settings because they require no chemical treatment, can be installed at the household or community level and provide consistent water quality, regardless of source variability.
Municipal Applications:
In municipal areas, water may already be treated, but issues like aging infrastructure, residual chlorine, chloramine, fluoride taste and odour concerns can affect water quality.
RO systems act as a final barrier, polishing municipal water to a higher purity standard for drinking and cooking.
Reverse Osmosis is Capable of Treating City or Rural Water Sources
Sequence of Water Treatment in Rural RO Applications
To ensure the longevity and effectiveness of a reverse osmosis system for purified drinking water, especially in rural settings, a proper treatment sequence is crucial:
1. Sediment Filtration: Removes large particles like sand, silt, and rust.
2. Water Softening or Iron Removal (optional): In areas with hard water or high iron levels, pre-treatment prevents reverse osmosis membrane fouling or scaling.
3. Sulphur and Tannin Removal (optional): in areas with elevated levels, pre-treatment prevents reverse osmosis membrane fouling or ruptures.
4. UV Sterilization or Chlorination (optional): In cases of high or known biological contamination, pre-disinfection treatment may be necessary.
5. Reverse Osmosis Filtration: The primary purification step that removes the majority of contaminants.
6. Post-Carbon Filter: Polishes the taste and ensures excellent final water quality.
7. Storage and Distribution: Clean water is stored and delivered through taps or distribution systems.
Exploring Reverse Osmosis (RO) vs. Ultraviolet (UV) Disinfection
Comparing ultraviolet disinfection to reverse osmosis is important when considering drinking water quality. The two differing technologies are summarized for how they operate and what each treats:
RO: Forces water through a semipermeable membrane to remove dissolved salts, heavy metals, chemicals, fluoride, pesticides and some microorganisms. Improving taste, reducing total dissolved solids (TDS), and removing a broad spectrum of contaminants from water.
UV: Exposes water to ultraviolet light that damages the DNA of microorganisms, preventing them from reproducing. Such as bacteria, viruses, and protozoa. It does not remove chemicals or solids. Fast, chemical-free, highly effective against pathogens.
ConclusionReverse osmosis is a versatile, powerful solution for delivering safe, high-quality drinking water, especially in rural areas where source water may be unreliable, prone to frequent changes or contaminated. With its ability to remove a wide range of pollutants and its scalable design, RO systems play a vital role in both individual households and community water systems. When properly maintained and pre-treated, these systems offer an affordable and long-term water purification solution for people everywhere.
Learn More About Water Quality and Treatment
For more information on water treatment and safety, refer to Jeff Wahl, a Canadian water educator, dedicated to raising awareness about effective water purification methods and the limitations of UV disinfection.
With twenty eight years of experience in the water treatment industry, Jeff has worked extensively in water quality assessment, filtration technologies, and public education on safe drinking water practices. He has conducted seminars, written articles, blogs, and advised private households on the importance of multi-barrier water treatment solutions. His expertise helps bridge the gap between technical knowledge and practical implementation, ensuring that homeowners have access to safe and reliable drinking water.
Volume 8 – Issue 2 Wahl H2O - Water Awareness
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