This document discusses various methods for removing hardness from water. It describes temporary hardness as caused by magnesium bicarbonate and magnesium carbonate, which can be removed by boiling water or adding lime. Permanent hardness is caused by calcium and magnesium salts and can be removed using the lime soda process, ion exchange process, or demineralization process. The lime soda process involves adding lime and soda ash to precipitate calcium carbonate and magnesium hydroxide. Demineralization uses cation exchange resins to exchange hydrogen for sodium ions, fully removing minerals from water.

1. WATER SOFTENING
 REMOVAL OF HARDNESS OF WATER
 PERMANENT HARDNESS
 TEMPORARY HARDNESS
 PERMISSIBLE LIMIT 75 TO 115 MG/L
BY-KRISHNA MURARI

2. METHODS OF REMOVAL OF
TEMPORARY HARDNESS
 1 BOILING : MAGNESIUM BICABONATE AND MAGNESIUM
CARBONATE CANNOT BE REMOVED.
 LARGE SCALE IS PRACTICALLY UNFEASIBLE.

3.  2 ADDITION OF LIME :
 LIME OR HYDRATED LIME IS ADDED TO WATER.
 CALCIUM CARBONATE AND MAGENESIUM HYDROXIDE IS
PRECIPITATED.

4. METHODS OF REMOVAL OF
PERMANENT HARDNESS
 LIME SODA PROCESS
 BASE EXCHANGE PROCESS OR ZEOLITE PROCESS
 DEMINERALISATION PROCESS

5.  LIME SODA PROCESS
 LIME AND SODA ASH ARE ADDED TO WATER
 CALCIUM CARBONATE AND MAGENESIUM HYDROXIDE PPT ARE FORMED
AND SEDIMENTED OUT IN A TANK
 CARBONATE HARDNESS IS REMOVED BY LIME
 NON CARBONATE HARDNESS IS REMOVED BY SODA

8.  RECABONATION PROCESS
 IN LIME SODA PROCESS LITTLE QUANTITY OF CAL. CARBONATE AND Mg
HYDROXIDE REMAIN AS FINELY DIVIDED PARTICLES AND MAY CAUSE
TROUBLESV BY GETTING DEPOSITED ON THE FILTER TO CAUSE
ENLARGEMENT OF SAND GRAINS CALLED INCRUSTATION OF FILTER
MEDIA

14. DEMINERALISATION PROCESS FOR
REMOVING HARDNESS
 REMOVAL OF MINERALS FROM WATER EITHER COMPLETELY OR
REDUCING THE MINERAL CONTENT
 DEMINERALISED WATER CALLED DEIONISED WATER AND IS VERY
SUITABLE FOR INDUSTRIAL PURPOSE SPECIALLY FOR STEAM RAISI NG IN
HIGH PRESSURE BOILER
 WATER IS PASSED THROUGH BED OF CATION EXCHANGE RESIN AND
THEN ANION EXCHANGE RESIN
 HYDROGEN IS EXCHANGED IN EXCEED OF SODIUM .
 THE CATION EXCHANGE RESIN ARE PHENOLALDEHYDE CONDENSATION
PRODUCTS.