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Hardness of Water

DEFINITION:

The property of water to form an insoluble curd with soap instead of lather. In other words it is the soap destroying property due to the presence of Bicarbonates, Sulphates and Chlorides of Calcium and Magnesium.

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TEMPORARY HARNESS: It is due to the presence of Bicarbonates of Calcium & Magnesium and can be removed by boiling.

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PERMANENT HARDNESS: It is due to the presence of Sulphates, Nitrates and Chlorides of Calcium & Magnesium.

Types of Hardness

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  • Hardness of water is expressed /a measured in terms of milli equivalent / liter

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  • 1 milli- equivalent = 50 mgs. of CaCO: / liter

Measurement of Hardness

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Soft water --- > =1 mEq. / litre

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Moderately hard water--- > =1-3 m.Eq. / litre

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Hard water ---- > =3-6 m.Eq. / litre

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Very hard water---- > =6 and >6 m.Eq. / litre

Classification of Hardness

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Reduced prevalence of,

1.Arteriosclerotic heart disease

2. Degenerative heart disease

3. Sudden death due to Cardiac arrest

4. Hypertension and

5. Tetany

Advantages of Hardness

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Are in the form of economic loss of a community and a country at large such as:

  1. More consumption of soap & detergents.
  2. More consumption of fuel due to scaling formation in the boilers in industries.
  3. Discoloration of foods
  4. Short life of clothes due to deposition of salts in fabrics.
  5. Disturbance of dyeing process
  6. High prices of products
  7. Decreased life of cisterns and Pipes

Disadvantages

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  1. FOR TEMPORARY HARDNESS : Boiling Addition of Lime.

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  • FOR PERMANENT HARDNESS: Addition of Lime Addition of Sodium Carbonate Base Exchange method / Permit it Process

Removal of Hardness

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