Decarbonisation makes subsequent treatment steps easier or more efficient and reduces the aggressivity of the water towards metallic and cement-based pipe materials. A technical limit is the pH-value at which calcite deposition starts.

The demands of German drinking water assignment regarding decarbonisation are listed in supplement 3, no. 18 Hydrogen ion concentration (pH value). Water must not be corrosive, and the calcite dissolving capacity at the outlet of the waterworks must not be higher than 5 g/m³. This demand is fulfilled if the pH-value is ≥ 7.7.
Decarbonisation can be carried out physically or chemically. The following passage describes a physical decarbonisation process with ≥ 7,7


Aeration columns

Physical deacidification is mostly realised in a downward flow of the water over packed colums with a counterflow of air, supplied by an external blower. The amount of removed carbon dioxide can be adjusted via the amount of air supplied by the blower. Frequent changes both in composition and quantity make an automated control system desirable.

The air blowers can be controlled via the water flow rate, or the pH value, but the delta-pH is even better suited. It describes the deviation of the current pH from that of the calcite saturated state, thus being a measure of the remaining calcite-dissolving capacity of the water after the treatment. The use of the delta-pH values as control variable allows an economic operation of the blowers, adapting their output to changes of both water quality and water flow rate.


Kuntze Measurement during deacidification

Our measuring system BalanceCon follows the pH-difference method described in DIN 38404-10: 1995-04. It is a complete measuring set-up, tested en-bloc and ready-to-use. In water treatment, BalanceCon is used to monitor and/or control the physical decarbonisation process. The accuracy of the measurement allows optimized operation even with changing raw water quality to save energy costs up to 75% by optimized frequency control of the blowers.  

Energieeffiziente Regelung

The measuring system BalanceCon allows the energy-efficient operation of aerator columns. Raw-water-based control of aerator frequency can lead to 75% reduction of energy costs. Read more in our

Balance Con

The system follows the pH-difference method described in DN 38404-10:1995-04.

More information about the system.