Correct option is D
The Zeolite process is used for the removal of permanent hardness of water. Permanent hardness is caused by the presence of soluble salts of calcium and magnesium, such as chlorides and sulfates, which cannot be removed by simple boiling.
Detailed Explanation of Options:
1. Boiling of Water:
Effective for removing temporary hardness caused by bicarbonates, but it does not remove permanent hardness.
2. Filtration Process:
Removes suspended particles but is ineffective in treating water hardness.
3. Lime Treatment:
Removes temporary hardness by precipitating bicarbonates as calcium carbonate.
4. Zeolite Process:
Effective for removing permanent hardness.
Zeolites are natural or synthetic minerals that exchange sodium ions with calcium and magnesium ions in hard water, thus softening the water.
