What is an EDI module?

Have you ever wondered how we get pure water in our homes and industries? It’s not magic, and it’s science! One of the amazing technologies behind water purification is the Electro Deionization (EDI) module. Do you want to know more about this fantastic technology? If so, let’s dive right in!

What is an EDI module?

What is an EDI (Electro Deionization) Module?

An Electro Deionization (EDI) module is a water treatment equipment that uses an electrical field to remove ionized and ionizable species from feedwater. The module comprises several chambers filled with ion-exchange resins and isolated by ion-exchange membranes. When water enters this module, the applied electrical field, oriented at right angles to the flow, propels ions through the resins and across the membranes.

EDI, also known as Continuous Electrodeionization (CEDI) or Continuous Deionization (CDI), is a technology that doesn’t require chemicals and significantly reduces ions in water. It employs cation and/or anion exchange resins that an electrical current continuously regenerates.

In addition to being a continuous and chemical-free process, EDI is often utilized to polish reverse osmosis (RO) permeate. It’s also a smart substitute for conventional mixed bed ion exchange (IX) and an effective replacement.

How Does an EDI Module Work?

An EDI module operates through a unique combination of ion exchange resins and electricity, fostering a continuous deionization process. Here’s how it works:

  1. As water flows into the module, the system applies an electrical field perpendicular to this flow. This field propels the impurity ions to move across the resins and membranes.
  2. These ions collect into concentrate streams rather than permanently sticking to the media. These streams can either be directed towards a drain or recycled.
  3. The EDI module employs ion exchange resins to continue the deionization process. The water traverses through the beds of these beads.
  4. When the water interacts with the ion-exchange beads, a transfer of ions occurs from the water to the beads, which in turn are replaced by hydrogen and hydroxyl ions in the water, resulting in pure water.
  5. Electrodeionization utilizes electricity to maintain a steady flow of ions out of the system. The ion exchange resins regenerate continuously, ensuring contaminants never oversaturate or exhaust the system.
  6. The EDI module applies functional currents to eliminate ionized substances from water while concurrently regenerating the ion exchange media.
  7. An EDI water system typically comes into play after a reverse osmosis or even a double pass ro system.

In summary, an EDI module efficiently purifies water through its innovative use of ion exchange resins and electricity, ensuring a continual process of deionization and regeneration.


An Electro Deionization module is essential to water treatment, working tirelessly to cleanse water by removing ionized substances. By incorporating this module after a reverse osmosis system, we can guarantee peak performance and ultra-pure water production. The real importance of this module is its capacity to uphold high purity standards and satisfy industry demands. It provides a green and efficient solution to diverse water treatment applications.

FAQs about EDI Modules

Where are EDI Modules commonly used?

EDI Modules are widely used in industries that require high-purity water. This includes pharmaceuticals, power generation, and microelectronics. They’re like the unsung heroes behind your medicines, electricity, and gadgets!

How efficient are EDI Modules at removing impurities?

EDI Modules can remove up to 99% of dissolved inorganic particles and ionizable species. That’s almost like getting a 99% in an exam – pretty impressive, right?

Are EDI Modules expensive to maintain?

Compared to other deionization methods that require regular chemical regeneration, EDI modules are relatively low-cost in maintenance. After all, who wouldn’t want an efficient and economical method?

What is the lifespan of an EDI Module?

With proper care and maintenance, an EDI Module can last for several years. It’s like having a reliable car running smoothly with regular servicing!

What makes EDI Modules different from other water treatment methods?

EDI Modules are unique because they combine two efficient water purification technologies – ion exchange and electrodialysis. This combination allows for continuous and chemical-free deionization, making it an environmentally friendly option.

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