Water treatment for surface pretreatment

Proper rinse water quality is crucial for the pretreatment system to ensure high product quality and operational reliability. 

Water quality is the key to product quality 

The pretreatment system performs cleaning, rinsing and preparation of the product surface. It is important for the product surface to be thoroughly cleaned of all dirt, oils, and contaminants before the surface coating process. The purpose of a pretreatment system is to ensure corrosion protection, optimal coating adhesion, superior optics and durable surfaces. Some or all of these factors together with proper rinse water quality is crucial.

Demineralized make-up water

In water-based pretreatment systems fresh make-up water is added due to evaporation, drag-over and to renew the water the different rinse baths. Demineralized make-up water with low salt and silica content is necessary to maintain the water quality of the rinse baths. 

The all-in-one CU:RO compact unit is an excellent make-up water solution that provides softening and reverse osmosis with only a small footprint and easy installation.

Learn more about CU:RO unit


Why water treatment?

The water treatment solution is related directly to the quality of the pretreatment process. An optimum solution designed to the surface pretreatment process ensures: 

Product quality

High surface finishing quality of your metal or plastic products


Low consumption

Low water consumption with rinse water recirculation


100 % clean

Products free of paint-wetting impairment substances, including silicone


Trouble-free operation

Trouble-free operation based on decades of experience



Recirculating rinse water

Recirculation over ion exchange resin reduces the amount of fresh make-up water needed. This is a sustainable solution to lower water consumption and even reduce cost.  

Water for reuse is treated in several steps:

1. Filtration of mechanical impurities
2. Adsorption of organic substances
3. Demineralization with ion exchange

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Important factors to consider for recirculation systems

Water quality

Some coating companies require that the dripping water must not exceed a maximum conductivity of 2 µS/cm. A demineralizer can normally produce a water quality of 5-20 μS/cm. With counter-current regeneration it can be as low as 1-5 μS/cm.

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Prevent bacteria

Microbial growth can cause mechanical impurities and hereby contaminate vital elements in the surface treatment system and the coating quality. This can be avoided by continuously circulating the rinse water through a UV-disinfection unit that efficiently kills 99,9 % of microorganisms.

See all UV units

Extended bath lifetime

Continuously recirculating each bath through a bag filter retains mechanical impurities, metal shavings and deposits. This reduces how often the baths must be discharged. Filter bags are available in a wide range of variations, including special types with activated carbon fibers for removal of organics.

See all bag filters

Water treatment designed for the surface treatment industry

We have collected all you need to know about optimum water treatment for surface treatment. Think water first if you want quality products - every time! 

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See references from the surface pretreatment industry

Get the optimum solution

Selection of unit depends on application, water quality, and water consumption. We are at your service to ensure the optimum solution based on our combined know-how. Fill in the form and let us get back to you.


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