Describe the water treatment process in municipal water supplies.

Municipal water treatment ensures safe and clean drinking water. The process involves the following steps:

1. Coagulation and Flocculation

Chemicals like alum (Al₂(SO₄)₃) are added to water to form flocs, which trap dirt and impurities.

Equation: Al₂(SO₄)₃ + 3Ca(OH)₂ → 2Al(OH)₃ + 3CaSO₄

2. Sedimentation

The heavy flocs settle at the bottom of the tank, allowing clear water to be separated.

3. Filtration

Water is passed through layers of sand, gravel, and charcoal to remove remaining particles and microorganisms.

4. Disinfection

Chlorine or ozone is added to kill harmful bacteria and viruses.

Equation: Cl₂ + H₂O → HOCl + HCl

5. pH Adjustment and Storage

Lime or carbon dioxide is added to balance pH. The purified water is then stored and supplied through pipelines.

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  4. What is water pollution?
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  6. What are pathogenic microorganisms?
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