Water treatment for District Heating

Water treatment is asset management

Prevent corrosion, deposits, and pipe fractures in your district heating system with the right water treatment. Correct water quality is essential for asset management.

Remove the oxygen

Oxygen is a prerequisite for corrosion to proceed. By removing the oxygen from the water before it enters the district heating network, the risk of corrosion is eliminated. Also, the need for oxygen binder is reduced, and in some cases it can be left out completely.

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Desalinate the feed water

Salts increase the conductivity of water and thus the risk of electrochemical corrosion. At the same time, salts provide good conditions for bacterial growth and microbial corrosion. Desalinated feed water removes the basis for corrosion to proceed. 

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Adjust the pH

Circulating district heating water should have a pH-value of 9.8 (± 0.2), as this ensures a stable, corrosion-proof magnetite coating on the inside of the district heating pipes. The pH is adjusted through dosing of sodium hydroxide (NaOH). By using desalinated water, the consumption of NaOH can be reduced by more than 90%. 

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Remove oxygen with a chemical free solution

Skanderborg-Hørning District Heating in Denmark has recently installed a membrane degasser for removing oxygen from the feedwater. Spend 2 min. in company with Lars Jørgen Dam, Head of production and hear how correct water treatment can prevent corrosion.

Read more about membrane degasser

Improve the water quality with correct water treatment

The main goal of correct water treatment is to prevent corrosion, deposits, and pipe fractures – in short, to extend the life of the plant. By removing salts and oxygen from the district heating water, as well as adjusting the pH value, the basis for corrosion is removed - including microbial corrosion.

Softeners have been a regular part of water treatment at district heating plants for many decades. But once calcium and magnesium is removed from the water, the presence of salts and oxygen will still affect the water quality. The conductivity will therefore be the same after softening.

Desalination by reverse osmosis results in high salt rejection up to 98%. As a bonus, desalinated water makes it easy to detect raw water intrusions so that security of supply can be maintained. The oxygen can be removed with a membrane degasser. A chemical-free solution, and thus the need for oxygen binder can be reduced by more than 90% and in some cases completely omitted.    

Reduce magnetite residue with a magnetic insert

Raw water intrusion, corrosion products, and suspended magnetite will inevitably occur in the district heating circuit causing pollution and at worst breakdowns. However, it can be delayed significantly by using the proper technologies.

As a minimum, particle filtration with bag filter and magnetic insert is recommended. A magnetic insert in the particle filter efficiently collects magnetite residue from the circuit water.

Go to bag filters

More about district heating

We have selected a number of publications that are relevant to you working with district heating water.

Mobile water treatment plant - ready for use!

If a temporarily water treatment problem arises, you can easily take care of it by renting a EUROWATER mobile water treatment plant. The video (2 min.) gives an example of, how the mobile water treatment plant handles a filling of thermal energy storage.

Whether you need drinking, disinfected, softened or demineralized water, we have a mobile solution.

Read more about our mobile water treatment plants

How can we help?

Our team of specialists are ready to answer your questions about pure water treatment solutions. 

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