Drinking Water Treatment: Corrosion protection and scale inhibition for drinking water

Some natural waters show such a constitution, that no corrosion (e.g. in water pipes or in the boiler) occurs, nor hardness (scale) deposits emerge; unfortunately this is rather an exceptional case.

If scale or rust formation occurs in pipes and/or in the warm water zone, something has to be ventured urgently, since drinking water systems can only be reconstructed with high investments.

For this purpose it is state of the art to adjoin (inject) special anticorrosive agents and hardness stabilizers to the drinking water.

Are chemicals in drinking water permitted? – Aren’t they harmful or unhealthy?

 This might be one of the first questions arising when considering drinking water treatment. But in this field the legislative body did his job: Additives to drinking water are only permitted when referred to by name in relevant standards (e.g. Austrian Food Register, Drinking Water Regulation 2001, ÖVGW and DVGW directives).

The substances denominated in these standards in detail, are either various silicates and phosphates, or alkalis for pH value adjustment. All these substances are natural occurring and registered as food additives.

Some natural waters (for example in primary rock regions) bear a considerable fraction of silicates, which then act as natural corrosion inhibitors.

The pH value too, which states, whether water is acid, neutral or alkaline, often is already within an ideal range and has therefore not to be adjusted.

Phosphates, as mentioned above, are natural materials which are essential for bone regeneration. Furthermore they are added to food to improve aspect and storage stability.

Ham or pork sausage or fish sticks contain much more phosphates than you might find in phosphate treated drinking water and what your body would ingest from this drinking water.

When adding at an adequate level and using food-grade raw materials a treatment of drinking water with corrosion protection agents is absolutely harmless and is applied worldwide for decades now.

Our additives are conform with the high requirements of the legislative authorities – corresponding certificates can be shown on demand.

Basically two problems in the realm of drinking water may occure:

1. Formation of scale:

Especially at higher water temperatures and a higher water hardness, very quickly (boiler) scale (calcium carbonate = lime) develops, which clogs pipes and corrupts heat transfer of heating elements and heat exchanging devices.

To prevent this scale formation an addition of special phosphates is highly effective: They work up to water temperatures of 80°C and up to a carbonate hardness of 14°dH – whereby scale deposits will be delayed for many hours.

In case of hard waters (> 14°dH) a water softening system with an affiliated dosing of a corrosion protection agent should be installed.

Our special products for hardness stabilization are:

IMPHOS-hart

MINIPOL-ST

2. Corrosion:

This will be induced by corrosive components of water as for example an excess of carbonic acid (and a therewith linked low pH value, below 7,0), elevated content of chlorides, nitrates, and extremely low water hardness (below 3°dH).

Even drinking water, which is basically not aggressive, may become corrosive due to softening or demineralization: By a reduction of total hardness a part of the associated carbonic acid is released and becomes corrosive.

Corrosion can be reduced by adding of alkalis (raises pH value) and by adding phosphates and/or silicates.

In particular a combined application of phosphates and silicates (concurrently charged) has proved its worth in practice. When conducted over a longer period this leads to very effective protective coatings which are able to stop corrosion thoroughly.

Our products for corrosion protection are covered by our product line IMPHOS.

A short word about magnetical and accordingly electrical water treatment

This concept summarizes all water treatment systems that want to fight formation of scale or corrosion without chemicals, but with magnetic or electric impact.

Systems of that kind are now known for more than 60 years – but an evidence of their effectiveness is in all cases missing.

There is only one way to be sure that no scale deposition will occur – and that is to remove in fact all hardness components of water, e.g. with the help of a softening or a demineralization system.

Dr. Ing. Franz Böhm – Your expert in conditioning of drinking water