Question

Given below is a jumbled sequence of the processes involved in a wastewater treatment plant. Arrange them in their correct sequence.
(a) Sludge is scraped out and skimmer removes floating grease.
(b) Water is made to settle in a large tank with a slope in the middle.
(c) Large objects like plastic bags are removed by passing wastewater through bar screens.
(d) Sand, grit and pebbles are made to settle by decreasing the speed of incoming wastewater.
(e) Wastewater enters a grit and sand removal tank. {NCERT Exemplar]

Answer 1

Answer:

1. Wastewater Collection

2. Odor Control

3. Screening

4. Primary Treatment

5. Secondary Treatment

6. Bio-solids handling  .

7. Tertiary treatment

8. Disinfection

9. Sludge Treatment

Explanation:

Answer 2

The correct sequence will be:

(c) Large objects like plastic bags are removed by passing wastewater through bar screens,

(e) Wastewater enters a grit and sand removal tank.

(d) Sand, grit and pebbles are made to settle by decreasing the speed of incoming wastewater.

(b) Water is made to settle in a large tank with a slope in the middle.

(a) Sludge is scraped out and skimmer removes the floating grease.

• We were supposed to arrange the given sentences in the correct sequence.
• We know that the given sentences indicate the steps involved in a wastewater treatment plant.
• And thus the first step must be to get rid of the big pieces of scrap from the water moving toward the smaller pieces.