A. Fill in the blanks:
1. Cleaning of water is a process of removing …………….. .
2. Wastewater released by houses is called ……………… .
3. Dried ……………… is used as manure.
4. Drains get blocked by ………………… and ………………. .
5. ……………… is a biogas.
B. Answer the following questions in short:
1. What is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.
2. Why should oils and fats be not released in the drain? Explain.
3. Describe the steps involved in getting clarified water from wastewater.
4. What is sludge? Explain how it is treated.
5. Untreated human excreta is a health hazard. Explain.
6. Name two chemicals used to disinfect water.
7. Explain the function of bar screens in a wastewater treatment plant.
8. Explain the relationship between sanitation and disease.
9. Outline your role as an active citizen in relation to sanitation.
10. What is done to improve sanitation?
11. The terms sewage, sewers and sewerage are interlinked with each other. Can you explain, how?
12. Why is air pumpeat to clarified water?
C. Tick (œ“) the correct option:
1. Study the following statements about ozone:
(i) It is essential for breathing of living organisms.
(ii) It is used to disinfect water.
(iii) It absorbs ultraviolet rays.
(iv) Its proportion in air is about 3%.
Which of these statements are correct?
(a) (i), (ii) and (iii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) All four
2. Wastewater is:
(a) water from leaking tanks
(b) water released in industrial waste
(c) water in drains of town
(d) all of the above
3. Sewage is a kind of:
(a) agricultural waste
(b) mining waste
(c) domestic waste
(d) both (a) and (c)
4. Open drains are a hazard because:
(a) they become the cause of spreading malaria and dengue
(b) emit foul smell
(c) solid wastes may block the water flow
(d) all of the above
5. The slurry mass left after secondary treatment of wastewater is:
(a) scum
(b) sludge
(c) effluent
(d) none of these
6. ………………. is a waterborne disease.
(a) Polio
(b) Malaria
(c) Cholera
(d) Flu
D. State ‘True’ or ‘False’:
1. To reduce the use of water means drinking less water. …………………..
2. Water is essential for breathing of living organisms. ……………….
3. An open drain can be breeding site for mosquitoes. ………………..
4. Fertilizers are a big source of water pollution in rural areas. ………………….
5. Using sewage water for gardening is a fair way of water recycling. ………………
E. Match the following:
| ‘A’ | ‘B’ |
| 1. Overpopulation | a. Water pollution |
| 2. Human faeces | b. Water management |
| 3. Sedimentation, filtration, chlorination | c. Wastewater treatment |
| 4. Reuse, Reduce, Recycle | d. Water scarcity |
| 5. Preliminary, primary and secondary treatment | e. Municipal water supply |
F. Solve the following crossword puzzle:
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-organisms which causes cholera
7. A chemical to disinfect water
G. Complete the following table:
