Deferrisation

Groundwater is the most important form of water used for drinking, irrigation and industrial purposes.
As groundwater often seeps through ferrous soils and rocks, iron is dissolved in the water.
As a result, the iron concentration is often above the maximum permitted level (0.2 mg/l).

Groundwater contains:

• metallic iron (Fe),
• iron(II) ions (Fe²⁺) and
• iron(III) oxide-hydroxide (Fe³⁺).

Iron II is generally soluble in an anoxic (oxygen-free) environment and is colourless. If groundwater is pumped to the surface, iron II forms iron III with oxygen, which is insoluble and has a rusty colour.

Areas of application
Deferrisation systems are generally used for well water, as it often has a high iron and manganese content.
Both substances lead to deposits in pipework and industrial systems, which can significantly impair the water quality and service life of the systems.
In addition, larger amounts of iron in the water cause an unpleasant odour and taste, which is undesirable in food production.

Some bacteria also need iron in order to grow. They then form a rusty, gelatinous sludge with the iron, which can block water pipes.
The presence of iron in process water can also lead to contamination of equipment, sanitary facilities and laundries.

Advantages of deferrisation

Using a deferrisation system and monitoring the iron content in the water helps to extend the service life of industrial plant and machinery and reduce maintenance costs.
Monitoring of the iron content of drinking water is mandatory (see Legal limits for iron).

Legal limits for iron
In accordance with legal regulations, drinking water may contain only very small quantities of iron, if any at all.
Limit values for drinking water (WHO guidelines):

• Iron 0,2 mg/l

For drinking water in Germany, the legal requirements of the German Drinking Water Ordinance (DIN 2000) must be met. These correspond to the limits specified by the WHO.

In addition to drinking water, process water is also usually treated before use so that it does not have high levels of iron.
The limit values for boilers are between 0.02 and 0.03 mg/l.

Which industrial sectors benefit from deferrisation systems?

• Laundries
• Mineral water industry
• Breweries
• Generation of steam using the
• electrode evaporation principle
• Hot water generation for
• bathrooms and hotels
• Swimming pool water
• Car washes
• Laser cutting machines
• Catering dishwashers
• Catering coffee machines
• Bottle washers