Question

Match the name of phenomenon with their respective definitions:

a.	Coagulation	1.	Allowing remaining particles to settle
b.	Disinfection	2.	Chemicals are added that cause small particles suspended in the water to clump together
c.	Flocculation	3.	Chlorine, ozone, hydrogen peroxide etc are used to remove bacteria
d.	Sedimentation	4.	Mixes the water with large paddles so that clump particles can be brought together into larger clumps

1. a - 1, b - 2, c - 3, d - 4
2. a - 2, b - 3, c - 4, d - 1
3. a - 2, b - 3, c - 1, d - 4
4. a - 3, b - 2, c - 4, d - 1

Answer 1

Correct Answer - Option 2 : a - 2, b - 3, c - 4, d - 1

Explanation:

Coagulation:

• The coagulation process involves the addition of the chemical (e.g. alum) and then a rapid mixing to dissolve the chemical and distribute it evenly throughout the water.
• It produces positive charges to neutralize the negative charges on the particles.

Flocculation:

• Now that the particles have a neutral charge and can stick together.
• The water flows into a tank with paddles that provide slow mixing and bring the small particles together to form larger particles called flocs. This process is called flocculation.

Plain Sedimentation: 

When the impurities are separated from suspending fluid by the action of natural forces alone (by gravity or natural aggregation of settling particles), such clarification is known as plain sedimentation.

Allowing remaining particles to settle

Disinfection:

Chemicals are added that cause small particles suspended in the water to clump together