Continuous Electro Deionisation (CDI)

reverse osmosis Continuous Electro Deionisation Continuous Electro Deionisation

Continuous Electro Deionisation (CDI)

This type of water treatment involves the use of two technologies to separate contaminants from water. Both membranes and ion exchange are used in electro deionisation. Often used as a replacement for traditional industry ion exchange units, electro deionisation is used in many types of businesses and is considered to be a very efficient as well as environmentally-friendly process for the treatment of water.

How Continuous Electro Deionisation Works

As water enters the electro deionisation unit, it gets diverted to individual cells. A DC charge is then applied across the cells, separating water molecules into hydroxyl and hydrogen ions. These ions then pass through cation and anion membranes before entering the concentrate chamber. This is what allows the resin beds within to be continuously regenerated.

The water which passes through the system, otherwise known as dilute is free of contaminants such as total dissolved colloids, chlorine and silica.

Benefits and Disadvantages

Electro deionisation has several advantages. First, electro deionisation doesn’t require the extra steps of other treatment processes such as waste neutralisation and chemical regeneration. Electro deionisation also offers lower operating costs due to no need for chemical regeneration solutions to be purchased. As well, no maintenance or labour is necessary in order to operate this type of water treatment system. As well, continuous electro deionisation units do not require two separate treatment units, which can add significantly to the complexity, size and overall cost of the system.

Fouling and scaling can occur with continuous electro deionisation systems. This is due to the fact that this type of system does not require regenerant chemicals, which can actually help to keep other types of water treatment systems such as membranes free of such debris. CDI is very popular in Pharmaceutical and Power Generation circles.

The potential down side of CDI

  • High capital cost
  • Must be fed with Reverse Osmosis

Is Continuous Electro Deionisation Right for You?

Despite its many advantages, you may be unsure about using electro deionisation for your application. When in doubt, visit Wychwood’s contact page to get in touch with one of our knowledgeable team members, who can advise you on the best alternatives for your business. Alternatively, you can review our range of continuous electro-deionisation units.

 

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