RO Technology
Understand the natural process behind reverse osmosis — and how AquTai uses it to produce pure, safe water.
Osmosis is a natural phenomenon found throughout nature. Reverse osmosis applies the same principle in reverse — using pressure to separate pure water from dissolved contaminants. It is one of the most effective methods for producing drinking water and process water at any scale.
Natural Osmosis
Osmosis is a natural process that balances two bodies of water separated by a semipermeable membrane. Water flows through the membrane from the less concentrated side (fewer dissolved contaminants) toward the more concentrated side to restore equilibrium.
A semipermeable membrane has microscopic pores that allow water molecules to pass while blocking larger contaminants. This movement continues until both sides reach equal concentration — or until an external force changes the balance.
Osmosis vs Reverse Osmosis
Reverse osmosis does not replace osmosis — it reverses the flow using applied pressure.
Water moves from a low-concentration solution toward a high-concentration solution until both sides are balanced. No pump or pressure is needed.
When pressure is applied to the concentrated side, water is forced through the membrane against its natural direction. Contaminants are left behind.
Reverse Osmosis
Reverse osmosis occurs when pressure is applied to water with a high concentration of dissolved contaminants. For example, when pressure is applied to saltwater, the salt is rejected and fresh water passes through the membrane — making it suitable for drinking.
Unfiltered feed water flows to the concentrated side of the RO membrane where pressure is applied. The pressure forces water molecules through the semipermeable membrane. Because contaminants and the membrane surface carry like electrical charges, like charges repel — preventing dissolved ions and particles from crossing to the clean side.
The purified output is called permeate. The concentrated waste stream left behind is called brine or concentrate.
Key Terms
A thin barrier with pores small enough to pass water molecules while rejecting dissolved salts, metals, and organic contaminants.
The unfiltered water entering the RO system — also called source water or influent.
The purified water that passes through the membrane — the product you drink or use in your process.
The waste stream carrying rejected contaminants, discharged to drain or further treatment.
In Practice
A complete AquTai reverse osmosis system uses multiple stages — not just the membrane alone.
Continue Learning
Explore the full AquTai RO guide — from system stages to real-world applications.
Prefilters, RO membranes, and post-filters that work together in every AquTai system.
Read article →From prefiltration and membrane separation to storage tanks and post-treatment.
Read article →Why clean drinking water matters for health, hydration, and everyday wellbeing.
Read article →Where reverse osmosis fits — homes, restaurants, laboratories, and industry.
Read article →Browse AquTai domestic, commercial, and industrial reverse osmosis products — or contact us for a tailored recommendation.