Fill in the blanks:

(a) Cleaning of water is a process of removing _______.

(b) Wastewater released by houses is called ________.

(c) Dried _______ is used as manure.

(d) Drains get blocked by ________ and ________.

What is sludge? Explain how it is treated.

Untreated human excreta is a health hazard. Explain.

Name two chemicals used to disinfect water.

Explain the function of bar screens in a wastewater treatment plant.

Explain the relationship between sanitation and disease.

Outline your role as an active citizen in relation to sanitation.

Here is a crossword puzzle: Good luck!

Across

3. Liquid waste products

4. Solid waste extracted in sewage treatment

6. A word related to hygiene

8. Waste matter discharged from human body

Down

1. Used water

2. A pipe carrying sewage

5. Micro-organism which causes cholera

7. A chemical to disinfect water

Study the following statements about ozone:

(a) It is essential for breathing of living organisms.

(b) It is used to disinfect water.

(c) It absorbs ultraviolet rays.

(d) Its proportion in air is about 3%.

Which of these statements are correct?

(i) (a), (b) and (c)

(ii) (b) and (c)

(iii) (a) and (d)

(iv) All four