Hardness control is widely used in drinking water treatment. Calcium products provide multiple functionalities for both processes – softening and remineralisation- applied here.


Hardness control has been used in drinking water treatment for more than 40 years. Two opposite processes are used here: 
  • Softening – water hardness reduction. Softening prevents scaling in water piping and households, reduces the soap and detergent consumption and hence chemical pollution in municipal wastewater.
  • Remineralisation – water hardness increase. Remineralisation protects steel piping from corrosion and improves sensoric quality of tap water. 
In water softening, lime is added to treated water to convert soluble Ca-bicarbonate to insoluble carbonate, which precipitates and is removed. 
A pellet reactor is the most effective device for this operation. It requires special lime with high dissolution rate for rapid reaction and eliminated lime carryover, causing water turbidity

Key applications

Key benefits of pellet reactor softening with AQUACALCO SW and MW range
  • Fully compliant with EN 12518 and national standards (KIWA-ATA)
  • Solubility index below 10 s (AQUACALCO SW 97/20, SW 97/30, MW 20 F, MW 25 F)
  • Extremely low aluminium content, crucial for sensitive users ad hospitals and medical centres (AQUACALCO SW from selected Belgian plants)
  • Available in a ready-made slurry (milk-of-lime) form  (AQUACALCO MW 20F, MW 25F)