The Importance of Feed Water Quality for EDI Systems
January 5, 2026
The Importance of Feed Water Quality for EDI Systems
In water treatment, EDI (Electrodeionization) is a key technology for producing ultra-pure water. However, the quality of the feed water is critical. Poor feed water can damage the EDI resin.
Why Feed Water Matters:
EDI uses ion-exchange resin to remove ions. If the feed water contains strong oxidants, like chlorine or ozone, they will attack and break down the resin structure. This is called “oxidation.” Once oxidized, the resin loses its ability to remove ions. The EDI module will produce low-quality water and must be replaced early.
Key Feed Water Requirements:
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No Oxidants: Remove all chlorine or ozone before the EDI.
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Low Hardness: Prevent scaling on the resin and membranes.
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Low Organics & Particles: Avoid fouling that blocks flow.
How to Protect Your EDI:
Always use proper pre-treatment, like Reverse Osmosis (RO), to clean the feed water. RO removes most oxidants, salts, and organics. Regular monitoring is also important.
In short, good feed water protects your EDI resin. This saves money and keeps your system running smoothly. Remember: protect the resin, protect the process.
IONPURE Brand EDI Feed Water Specifications:
| Feed Water Source | RO Permeate |
| Feed Water Conductivity Equivalent ,including CO2 and Silica | <40 μS/cm |
| Temperature | 41-140oF(5-60℃) |
| Inlet Pressure | <100 psi(6.9 bar) |
| Maximum Total Chlorine(as cl2） | <0.02ppm |
| Silica(SiO2) | <1ppm |
| Sulfide(S2) | <0.01ppm |
| Manganese(as Mn/Fe) | <0.01ppm |
| Total Hardness(as CaCO3 | <1.0ppm |
| Dissolved Organics(TOC as C) | <0.5ppm |
| PH | 4-11 |
Chinese Brand EDI Feed Water Specifications:
| Feed Water Source | RO Permeate |
| Feed Water Conductivity | <10 μS/cm |
| Silica(SiO2) | <1ppm |
| Sulfide(S2) | <0.01ppm |
| Manganese(as Mn/Fe) | <0.01ppm |
| Total Chlorine(as CL2) | <0.02ppm |
| Total Hardness(as CaCO3 | <1.0ppm |
| Dissolved Organics(TOC as C) | <0.5ppm |
| PH | 4-11 |
| Temperature | 5-60℃ |
| Inlet Pressure | <100 psi |