Hi Sandeep, chemical ...

Hi Sandeep, chemical softening calculations (using lime or sodium carbonate) have been put into a useful tool - a product of the South African Water Research Commission - called STASOFT version V.  This allows you to enter your water chemistry and select a final hardness level.  It will then calculate the chemical addition required depending on the chosen softening chemical.  The programme also allows you to ensure the water is stable after treatment (Langelier Saturation Index).  Other practiced methods of softening are ion-exchange and membrane processes (nano-filtration).

Silica reduction in wastewater will also be achieved by addition of lime (and hence the water softened at the same time).  Alternatively membrane processes may be considered (microfiltration).  However it depends on what the treated water will be used for as this may be costly.