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In industries such as pharmaceuticals, microelectronics, cosmetics, and high-precision laboratories, water quality is critical. In these cases, potable or purified water isn't enough—ultrapure water (UPW) is required, virtually free of particles, ions, microorganisms, and organic matter.

But how is this level of extreme purity achieved? Here are the key stages in the process:

1. Pretreatment

It all begins with removing large solids and organic contaminants. Technologies used at this stage include:

• Multimedia filtration (sand, anthracite)

• Activated carbon to remove chlorine and organic matter

• Chemical dosing to control scaling and adjust pH

This step is crucial to protect the membranes and resins used in later phases.

2. Reverse Osmosis (RO)

Reverse osmosis is the backbone of the system. Using semipermeable membranes, it removes up to 99% of dissolved solids, heavy metals, bacteria, and viruses. This technology significantly reduces the electrical conductivity of the water, bringing it closer to the required ultrapure levels.

3. Polishing with Ion Exchange Resins

To achieve even lower conductivity levels (<0.1 µS/cm), mixed-bed ion exchange resins are used to remove the remaining ions. These resins are regenerable and require constant monitoring.

4. Final Filtration and Microbiological Control

The final stage includes microfiltration or ultrafiltration to remove submicron particles, and ultraviolet (UV) light to ensure complete disinfection. Some systems also include ozone as an additional disinfectant.

Why is purity so important?

Even minimal impurities in the water can affect the quality of the final product, damage equipment, or compromise critical processes. That’s why proper system design and constant monitoring of parameters like TOC, TDS, and pH are essential.

Conclusion

Ultrapure water production is a complex, highly technical process that combines multiple treatment technologies. Each stage plays a vital role in achieving maximum water purity, which is crucial for industries where there is zero margin for error.