Electrodeionization: Continuous Water Purity
Electrodeionization (EDI) is a high-performance water treatment process that produces water with very low conductivity, without the need for chemical regeneration.
It combines the principles of ion exchange demineralization and electrolytic migration, ensuring continuous, stable, and environmentally friendly purification.
This technology is particularly used in the pharmaceutical, electronic, laboratory, and high-purity industries, where water quality is a critical process factor.
At SFEC, we design, install, and maintain custom electrodeionization units, tailored to our clients’ specific needs.
Our solutions are integrated into comprehensive treatment lines including reverse osmosis, ultrafiltration, softening, and UV sterilization.
Objective: to produce ultrapure water continuously, without adding chemicals, while optimizing operating costs and process reliability.
Operating Principle of Electrodeionization
The process relies on the combination of an ion exchange resin and selective membranes, activated by a continuous electric field.
Reverse Osmosis Pre-treatment
Water is first cleared of most dissolved salts.
Ion Exchange and Electrolytic Migration
Under the effect of the current, residual ions migrate through the membranes for removal.
Continuous Production of Demineralized Water
The resin is continuously regenerated by the electric field, without the use of acids or caustic soda.
Control and Supervision
Conductivity, voltage, and flow rate are monitored in real-time to ensure consistent quality.
Our Custom Electrodeionization Systems
Compact EDI Modules
- Designed for low to medium flow rates
- Simple integration after reverse osmosis
- Reduced maintenance, silent operation
Industrial EDI Skids
- Complete assemblies on stainless steel frames
- Integrated automation and PLC supervision
- Flow rates up to several m³/h
Pharmaceutical EDI Systems
- Components compliant with GMP / FDA / USP standards
- Materials compatible with pharmaceutical grade water (EP, WFI)
- Complete documentary validation
Hybrid EDI Solutions
- EDI / RO combination for enhanced purity
- Possibility of double pass reverse osmosis + EDI
- Ideal for laboratories and the microelectronics industry
Advantages of Electrodeionization
Electrodeionization combines ion exchange and electric current to continuously produce ultrapure water, without adding chemicals.
Continuous production of ultrapure water
Consistent quality meeting the most demanding standards.
No chemical regeneration
Complete elimination of acids and bases used in conventional deionizers.
Low operating costs
Reduced maintenance and extended module lifespan.
Environmentally friendly process
Continuous operation without polluting discharges.
Stable and online-controlled water quality
Automated supervision and complete traceability.
Areas of Application
- Pharmaceutical and biotechnology industry
- Production of purified water and WFI
- Electronics, microprocessors, and optics
- Analytical and research laboratories
- High-pressure steam plants
- Cosmetics and fine chemicals industry
Questions and Answers
What is the Difference between Electrodeionization and Conventional Demineralization?
EDI does not require chemical regeneration, unlike resin demineralizers.
Does Electrodeionization Replace Reverse Osmosis?
No, it complements reverse osmosis by eliminating residual ions.
What Level of Purity is Achieved?
Up to 0.055 µS/cm (resistivity of 18.2 MΩ·cm).
Is Pre-Treatment Required before EDI?
Yes, water must be pre-treated (often by reverse osmosis) to ensure module longevity.
What Maintenance Does an EDI System Require?
Very low: only conductivity control and periodic rinses.
SFEC, global water treatment expert
Electrodeionization is a key step in high-purity water production.
At SFEC, we integrate EDI modules into complete treatment chains:
- Filtration to remove particles,
- Reverse osmosis for demineralization,
- Electrodeionization for final polishing,
- UV sterilization for final disinfection.
Our teams support each client from design to maintenance, ensuring optimal performance and complete traceability.
Are you looking for a high-performance and sustainable solution for ultrapure water production?
Our SFEC experts design tailored electrodeionization systems to meet your industrial requirements.