What is Electrodeionization EDI in Water Treatment? How Does it Work?


Are you looking for ways to treat and purify water for industrial, or commercial use? If so, electro-deionization (EDI) is a highly efficient technology that you should consider. What is Electrodeionization? This technique of water treatment has been used since the early 1960s and continues to be an effective solution.

In this blog post, we’ll provide an overview of EDI technology along with its advantages, disadvantages, and best practices to help you make an informed decision.

Cost of Purifying Water Using Electrodeionization Technology

 ➢What is Electrodeionization Technology?

Electrodeionization, or EDI for short, is a water treatment technology that uses an electric field to remove ions and other dissolved impurities from water. It is an ion exchange process, but it uses electricity rather than chemicals to drive the ion exchange process. Water, usually treated by a reverse osmosis system, passes through a series of ion exchange membranes and ion exchange resins in an EDI system. The membranes and resins alternately carry positive and negative charges, which create an electric field.

 ➢How Electrodeionization Works?

The electrodeionization working principle is simple. Electrodeionization (EDI) enables the selective directional migration of ions through the action of a direct current electric field. The desalination chamber of the electrodialysis is filled with ion exchange resin, and the mixed bed resin is regenerated by the dissociation of water so that the dissolved ions and other impurities in the water are attracted to the charged membrane and resin, so as to realize the selection of the exchange membrane. The permeability realizes the purpose of purifying water quality and obtaining ultrapure water.

Between a pair of electrodes of the electrodialysis, there are usually multiple sets of negative membranes, positive membranes, and separators (A, B) alternately arranged to form a concentrated chamber and a dilute chamber. In the water in the dilute room, the cations migrate to the negative electrode and pass through the positive membrane, and are intercepted by the negative membrane in the concentrated chamber; the anions in the water migrate to the positive electrode in the negative membrane, and are intercepted by the positive membrane in the concentrated chamber, so that the number of ions in the water passing through the dilute chamber gradually decreases, becomes fresh water.

Learn about the electrodeionization process with the electrodeionization process flow diagram below.

electrodeionization process flow diagram

 ➢What is EDI Water?

Ultrapure water is very close to high-purity water, that is, there is only H20 in the water. Except for hydrogen ions and hydroxide ions, there are hardly any other electrolytes that come close to water in the true sense. Its resistivity is 18.2 MΩ.cm (25°C) and TOC < 10 ppb. Does not contain organic substances such as bacteria, viruses, and chlorinated dioxins.

 ➢The Benefits of Using Electrodeionization Technology.

Electrodeionization is a technology that is used to purify water by removing ions and dissolved impurities from it. The main benefit of using this technology is that it can produce high-quality, highly-purified water that is free of a wide range of contaminants. This makes it ideal for use in a variety of applications, including industrial processes, medical applications, and drinking water treatment. In addition to producing high-quality water, electro deionization also has a number of other benefits, including:

  • It is a continuous process, which means that it can produce a steady stream of purified water without the need for frequent shut-downs or interruptions.
  • It uses electricity rather than chemicals to drive the ion exchange process, producing high-purity water even without the use of potentially hazardous chemicals.
  • It is a relatively low-maintenance technology, which means that it requires less frequent cleaning and servicing than some other water purification systems.
  • It is highly efficient, which means that it can remove a wide range of contaminants while using relatively low levels of energy.
  • It is a scalable technology, which means that it can be used to treat large volumes of water or small volumes, depending on the needs of the application.
  • It is a versatile technology, which means that it can be used in a variety of different water treatment systems, including standalone units and integrated systems.

Benefits of Using Electrodeionization Technology


 ➢Application Fields of Electrodeionization Technology.

Electrodeionization (EDI) is a technology that is used to purify water by removing ions and other impurities from it. It is commonly used in a variety of applications, including the production of ultra-pure water for industrial and scientific use, the treatment of drinking water, and the desalination of seawater.

EDI technology is also commonly used in the pharmaceutical industry, for example, to produce sterile water for injections and other medical purposes. Additionally, EDI technology is sometimes used in wastewater treatment to remove ions and other contaminants from wastewater, making it safer to discharge into the environment. Other application fields include:

  • Electronics & Electricity
  • Laboratory
  • Food factory
  • Biopharmaceutical
  • Oil & gas
  • Chemical process water
  • Cosmetics factory.

Figure 2 Water Treatment Systems in the Oil and Gas Industry

➢What Contaminants Can Electrodeionization Remove?

Electrodeionization (EDI) is a powerful water treatment technology that can remove a wide range of contaminants from water. It uses specialized ion exchange membranes and electrodes to strip dissolved ions, metals, organic compounds, colloids, and objectionable minerals from the water.

As a result, EDI produces high-quality water with low levels of total dissolved solids (TDS) and conductivity. Some of the contaminants it can remove include chlorine, sodium, calcium, iron, nitrates, sulfates, silica, boron, fluoride, turbidity, ammonia, and organic compounds such as polychlorinated biphenyls (PCBs).

➢Comparing Electrodeionization to Other Water Treatment Technologies.

Electrodeionization (EDI) is an emerging technology that has revolutionized water purification and desalination processes. It offers a number of benefits over other traditional water treatment technologies, including more efficient operation, lower energy consumption, fewer chemicals used, and higher quality water outputs. Underneath, we are going to look at how EDI fares in comparison to other remarkable water purification technologies.

EDI Units

· Electrodeionization VS Deionization.

Electrodeionization (EDI) and deionization are both methods of removing ions from water to make it purer. Both methods use ion exchange resin to remove ions from the water, but they differ in how they regenerate the resin. In deionization, the resin is regenerated using chemicals, such as hydrochloric acid and sodium hydroxide. This method is relatively simple and can be effective at removing ions from water, but it can produce wastewater as a byproduct.

In contrast, EDI uses electricity to regenerate the resin. This eliminates the need for chemicals and produces no wastewater. EDI is therefore considered a more sustainable and efficient method of deionizing water. However, it is also more complex and expensive than traditional deionization.

Figure 3 Electrodeionization (EDI)

· Reverse Osmosis vs Electrodeionization

Electrodeionization (EDI) and reverse osmosis (RO) are two different water treatment technologies that are used to purify water. EDI uses electric fields to remove ions and other impurities from water, while RO uses pressure to force water through a semipermeable membrane to remove impurities.

One major difference between the two technologies is that EDI can produce water with a very low level of dissolved ions, which makes it suitable for applications where ultra-pure water is required, such as in the semiconductor industry. RO, on the other hand, is typically used for applications where the removal of a broader range of impurities, such as bacteria and viruses, is more important.

Another difference between the two technologies is that EDI is a continuous process, meaning that it can produce purified water at a constant rate. RO, on the other hand, is a batch process, which means that it can only produce purified water in batches. Overall, both EDI and RO are effective technologies for water purification, but they are best suited for different applications depending on the specific requirements for the purified water.

Figure 4 Reverse Osmosis.

· Electrodeionization VS UV Sterilization.

Electrodeionization (EDI) is a water treatment technology that uses electric fields to remove ions from water. This process is often used to produce high-purity water for industrial and pharmaceutical applications. In contrast, UV water sterilization uses ultraviolet (UV) light to kill bacteria and other microorganisms in water. UV sterilization is often used to disinfect drinking water and other water supplies to make them safe for human consumption.

➢The Cost of Purifying Water Using Electrodeionization Technology.

Electrodeionization (EDI) is a reliable and efficient way to purify water continuously, which makes it the technology of choice for many industrial processes. It has been tested and proven to be effective in the removal of dissolved organic compounds, heavy metals, salts, and other contaminants from both brackish water and seawater.

The cost of treating water using EDI technology can vary depending on the type and size of the project. Generally, installation costs may be higher compared to other water purification technologies but the operational cost is usually lower. EDI also requires minimal maintenance and servicing which further reduces long-term expenses.

Additionally, EDI systems are designed with energy-saving features that reduce the cost of electricity consumption. It is also possible to install an EDI system in a modular configuration which allows for increased scalability and flexibility, bringing down initial installation costs.

Electrodeionization Water Purification System


➢How to Properly Take Care of Your Electrodeionization Water Purification System?

Proper care and maintenance of an EDI system are essential to ensure its effectiveness and longevity. Here are some tips for taking care of your EDI system:

  • Keep the system clean: Regularly clean the EDI modules, membranes, and other components to remove any buildup of contaminants.
  • Monitor the water quality: Regularly test the water to ensure it meets the desired purity standards.
  • Maintain the electrical connections: Check the connections regularly to ensure they are secure and not corroded.
  • Use high-quality water: Use high-quality feed water to maximize the effectiveness of the EDI system and extend the life of the membranes.
  • Follow the manufacturer’s instructions: Make sure to follow the manufacturer’s instructions for operating and maintaining the EDI system.

It’s also important to regularly service your EDI system to ensure it is operating at peak performance. This may include replacing the membranes, cleaning the modules, and other routine maintenance tasks. A qualified service technician can help with this.


Electrodeionization eliminates the need for resin regeneration and is more efficient and effective than traditional deionization processes. If you are looking for a high-quality water electrodeionization system, look no further than NEWater. We have the latest and most advanced equipment available on the market today, and we can help you get up and running quickly and easily. Contact us today to learn more about our products and how they can benefit your business.

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