Electrodeionization (EDI) Water Treatment Systems

What Is Electrodeionization?

Electrodeionization (EDI), also known as Continuous Electrodeionization (CEDI), is an advanced water purification technology that continuously removes ionized and ionizable impurities from water using direct current (DC) power—without the use of chemicals.

Unlike traditional mixed-bed ion exchange systems that require periodic regeneration with hazardous acids and bases, EDI is a chemical-free solution that combines ion exchange resins with electrically active membranes and a DC electrical field. This process efficiently polishes reverse osmosis (RO) permeate to deliver consistent, ultra-pure water.

Benefits of EDI Water Purification

  • Chemical-Free Operation – No acid or caustic regeneration required
  • Continuous Process – No shutdowns or downtime for regeneration
  • Low Operating Costs – Reduced consumables, disposal, and labor
  • Environmentally Friendly – No hazardous chemical storage or waste
  • Consistent Water Quality – Resistivity often >15 MΩ·cm
  • Compact Footprint – Smaller resin volume, high efficiency
  • Bacteriostatic Environment – Inhibits bacterial growth inside the module

 

EDI Membrane Graphic

How Electrodeionization Works

EDI modules consist of multiple chambers filled with ion exchange resins, separated by ion-exchange membranes. As water flows through the chambers:

  1. Ionized impurities are attracted by the applied electrical field.
  2. Ions migrate across membranes into concentrate streams.
  3. Purified water continues through the system, free from dissolved inorganics.
  4. The resins are continuously regenerated by the electric field, eliminating the need for chemical regeneration.

Because contaminants are diverted into separate concentrate channels, the resins are not exhausted and can operate for years with minimal maintenance.

Applications of EDI/CEDI Systems

Our EDI systems are ideal for any industry requiring high-purity water without chemical regeneration:

  • Electronics Manufacturing
  • Pharmaceutical & Biotech
  • Power Generation & Boiler Feed Water
  • Laboratory & Analytical Applications
  • Cooling Tower Makeup Water
  • Food & Beverage Production

Why Choose ALSI for Your EDI System?

  • Reliable, Long-Term Performance
  • Eco-Friendly, Sustainable Water Treatment
  • Expert Support for System Integration and Maintenance
  • Engineered for Compatibility with RO and Pretreatment Systems

Whether you’re looking to upgrade an aging ion exchange system or build a new high-purity water treatment train, our EDI solutions offer unmatched performance, cost-efficiency, and regulatory peace of mind.

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