1. Softened Water
Softened water mainly removes calcium and magnesium ions which cause water scaling. It uses ion exchange resin to replace Ca²⁺ and Mg²⁺ with sodium ions.
- Key index: Hardness is greatly reduced, no obvious scaling
- Limitation: It cannot remove dissolved salts, heavy metals, bacteria or organics. TDS value almost does not change.
- Typical applications: Boiler feed water, cooling circulation water, laundry, pre-treatment for RO system.
- Common equipment: Water softener / ion exchange softening system
2. Purified Water (RO Pure Water)
Purified water in industrial field usually refers to RO reverse osmosis water. Raw water passes through reverse osmosis membrane to remove most dissolved salts, colloids, bacteria, suspended solids and heavy metals.
- Key index: TDS greatly reduced, conductivity usually 1–10 μS/cm
- Limitation: It can remove most ions, but cannot reach ultra-high resistivity
- Typical applications: Food & beverage production, cosmetic water, general process water, raw water for EDI.
- Common equipment: Single-stage / double-stage RO water purification system
3. Deionized Water (DI Water)
Deionized water removes charged ions in the water by ion exchange resin or EDI. It can be divided into two types: mixed bed deionized water and EDI continuous deionized water.
- Key index: Low ion content, resistivity usually 1–18.2 MΩ·cm (depends on process)
- Limitation: It only removes ions, organic matter and particles still need to be filtered by RO or UF
- Typical applications: Electroplating, cleaning, chemical preparation, laboratory common water
- Common equipment: Mixed bed resin, EDI module, RO+EDI system
4. Ultrapure Water (UPW)
Ultrapure water is the highest grade of industrial water. It removes almost all ions, particles, bacteria, dissolved organics and colloids. It is usually made by RO + EDI + polishing mixed bed + ultrafiltration.
- Key index: Resistivity up to 18.2 MΩ·cm @25℃
- Limitation: High production cost, easy to be polluted by air and pipeline
- Typical applications: Semiconductor wafer cleaning, lithium battery, high-precision electronics, pharmaceutical injection water
- Common equipment: Double stage RO + EDI + polishing mixed bed ultrapure water system
Quick Comparison Table
| Water Type | Core Removal Target | Typical Quality Index | Main Process |
|---|---|---|---|
| Softened Water | Calcium & magnesium ions (hardness) | Hardness < 0.03 mmol/L | Ion exchange softener |
| Purified Water | Most salts, bacteria, colloid | Conductivity 1~10 μS/cm | Reverse Osmosis (RO) |
| Deionized Water | Charged ions | Resistivity 1~15 MΩ·cm | Mixed bed / EDI |
| Ultrapure Water | All ions, particles, TOC, bacteria | 18.2 MΩ·cm @25℃ | RO + EDI + polishing + UF |
How to choose the right water for your factory?
- If you only need to prevent boiler and pipeline scaling → Choose softened water
- If you need low-salt process water for food, cosmetic → Choose RO purified water
- If you need deionized water for electroplating and general cleaning → Choose RO+EDI deionized water
- If you are in semiconductor, lithium battery, high-precision electronic industry → Choose ultrapure water system
Final Tips
Many customers mix up deionized water and ultrapure water. Ultrapure water belongs to the highest level of deionized water, but ordinary deionized water cannot reach ultrapure water standard. Ticktock Water can customize water treatment systems according to your raw water report and water requirement, including softener, RO purified water machine, RO+EDI deionized water system and ultrapure water equipment. Send your demand to get a free solution.
