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Water with a high mineral concentration is known as hard water. Dissolved calcium and magnesium are the major causes of hard water. There are two types of hardness – temporary and permanent.
Temporary hardness refers to the hardness of water induced by calcium bicarbonate. On the other hand, hardness linked with other mineral salts is called permanent hardness.
Hard water produces residues in dishwashers, makes less foam with detergents and soap, causes textile wear, and leads to reduced water pressure via taps.
Hard water does not pose any major health risks, but it might cause dry skin and hair. Boiling can reduce temporary hardness but not permanent hardness. Hard water softening can be done at home by making it pass through resin coated with sodium.
This dissolution of minerals occurs during normal water cycles, and the grade of hardness sometimes depends on the geological area.
Detection of hard water
The following signs can detect hard water:-
- Stains in sink and tubs
- Clothes wear out easily
- Dull colour of clothes
- White, chalky residue on dishes and pipes
- Dry skin and dry hair
- Less lather with soap and detergents
Disadvantages of hardness
Hard water has several advantages to the human body, like strengthening bones and teeth, reducing constipation, and improving gut health. But hard water being a problem is a long list to explain.
Soap scum
When two substances react, their atoms and molecules react with each other and form a product. When hard water and soap react, magnesium or calcium ions in hard water react with soap molecules and form a precipitate. Precipitation is a type of chemical reaction where the product is solid. Here, soap scum is the precipitate, which is insoluble. It may look more like soap molecules, but it doesn’t lather.
Clogged pipes
The sedimentation of minerals from hard water forms a plaque in pipes resulting in their clogging. The flow pressure is also reduced due to this clogging.
Stains
Hard water leaves stains everywhere. Due to dissolved minerals, cloudy stains will be present in tubs, dishes, and pipes. Over time, because of continuous deposition, these stains become hard to remove.
Dry skin and hair
We have sebaceous glands and sweat to keep our skin hydrated and not flaky. When we use hard water, magnesium and calcium ions clog our pores. It leads to flaky, irritable dry skin and hair.
Faded and brittle laundry
As we mentioned earlier, soap and detergents react with hard water forming soap scum and less lather. Because of this, hard water does not clean laundry properly and also leaves behind scum in clothes, which becomes hard on drying. As a result, clothes appear faded and brittle.
Wearing out of appliances
Accumulation of minerals results in plaque formation. These plaques cause increased corrosion. These deposits are an issue in equipment that generate steam. Hard water causes the overheating of equipment (boilers) resulting in fuel wastage and equipment deterioration before its manufactured lifespan.
Methods of removal of hardness
The temporary hardness of water can be removed by boiling. While boiling, soluble salts become insoluble and precipitate. Permanent hardness cannot be removed by boiling since sulphate and chloride do not precipitate at elevated temperatures. There are several methods of removing permanent hardness, like
- Clark’s process
Ca(HCO3)2 + Ca(OH)2 → 2CaCO3 + 2H2O
- Calgon method
Calgon reacts with hard water and precipitates with salts, which is easier to remove from water.
- Using ion-exchange resins
The unwanted ions in hard water are exchanged with more agreeable ions like sodium ions.
- Using washing soda
Conclusion
A condition of water with a high mineral concentration is known as hard water. Dissolved calcium and magnesium are the major causes. Temporary hardness refers to the hardness of water induced by calcium bicarbonate. Hardness linked with other mineral salts, on the other hand, is permanent hardness.
Hard water has several advantages to the human body, like strengthening bones and teeth, reducing constipation, and improving gut health. But hard water has a long list of problems attached to it.
Disadvantages of hardness include the formation of soap scum, cloud-like stains, clogged pipes, dry skin and hair, faded and brittle laundry, and corrosion and deteriorated appliances. Temporary hardness can be removed by boiling, but permanent hardness requires other methods. Water softening at home can be done using resin coated with sodium. Other methods of removing hardness include Clark’s process, Calgon process, and using ion exchange resin.
