The Industrial Water Purification Blog

3 Ways To Achieve Pure Industrial Water Through A DI Water System

Posted by Peter Wood on 28-Nov-2017 15:18:10

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Businesses needing large quantities of pure process water on demand can truly take advantage of DI systems to ensure they get the necessary water for their technical processes. There are several ways in which you can implement a deionisation (DI) water system in an industrial setting. 

Here are the top three ways of achieving pure industrial water through the implementation of a DI water system:

1) Exchangeable Vessel System

One way of implementing a DI water system is to treat the water supply by using temporary (exchangeable) vessels. These vessels contain the required media to deionise the water, such as a mix of anion and cation reins, to remove minerals from the incoming mains water supply. The water then moves downstream to the other parts of the treatment plant where it may receive additional treatment – such as UV sterilisation or filtration, for bacterial control.

The vessel system is modular as such with several resin types available to treat different incoming water, in other words the resins can be selected to suit a specific application, and when the resins have exhausted, it is easy to swap out the individual vessels for resin regeneration. In this way, you will never face the problem of suddenly using industrial water that does not have the same level of demineralisation that you normally get with the fully working vessels, or of taking the whole system offline while you maintain the resin beds.

Single bed systems generally have a smaller footprint than two bed systems, making them well suited to restricted environments, or for incorporation into a larger water treatment plant.

2) Two Bed DI System

A DI water system can fully replace your existing system for achieving pure industrial water, if required. This is a system which provides complete processing through the use of two separate ion exchange units.

The first vessel or bed is filled with a matrix of cation exchange resin in hydrogen form to capture & exchange dissolved salts and metals such as Ca, Mg and Na for hydrogen ions. The treated water then passes to a bed of anion exchange resin in hydroxide form to capture and exchange Cl and SO⁴ ions for hydroxide ions.

The two bed solution is applicable in high-volume situations which would otherwise depend on reverse osmosis (RO) technology. Two bed deionization is economically viable as a stand-alone product when operating on a TDS (Total Dissolved Solids) of 1000ppm or lower. 

The two-bed system works directly with the industrial water supply meaning the water does not receive upstream treatment in the form of additional filters and water softeners. However, since this process uses special regenerant chemicals, the industry needs to practice safety laws and make sure that the supplies are properly placed in a secure area. DI systems are not always suitable for businesses where chemicals could negatively affect their final product – such as food manufacture.

For regular users of demineralised water, investing in a DI plant in house is certainly cheaper long term than having to purchase water from a third party, sometimes with a payback period of less than 2 years.

3) Electrodeionisation (CEDI)

Deionisation systems with resins being continuously charged by an electric current, avoiding the need for chemical regeneration, have become more reliable and economical in recent years. The process is still a deionisation one with cation and anion resins at its core, but in the case of CEDI an electrical current is applied to attract and thereby remove the contaminants bonded to the DI resins which are sent into a waste stream. In this way the resins are cleaned and maintained in situ without the need for chemical regeneration onsite like a two bed system offers, or off-site in the case of an exchangeable mixed bed vessel.

In order for the CEDI system to work effectively, it is essential to pretreat the incoming water to a specific level of purity by selecting equipment upstream to match the incoming mains water characteristics. This will certainly involve an assessment of the incoming water to identify anything that might compromise the effectiveness of the CEDI process. The equipment chosen to pretreat the water typically includes a membrane stage such as reverse osmosis with upstream pretreatment.

This system, whilst having a larger capital cost, can produce savings over the long term when compared with other technologies, it also produces a continuous repeatable level of water purity without the use of harmful chemicals making it suitable for clean environments.

Find Out More About Industrial Deionisation

If you are still not clear about which DI plant would work best for you, then please take a look at our FREE Guide to Industrial Water Deionisation. This eBook will help you make the right investment decision for your facility. For all other questions, please don’t hesitate to get in touch with one of our water treatment experts by phone or email.

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Topics: Deionisation

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