THESE NOTES ARE PREPARED ACCORDING TO JKBOSE SYLLABI IN SIMPLIFIED AND CONCISE PATTERN
Exercises
1. Fill in the blanks:
(a) Cleaning of water is a process of removing Pollutants .
(b) Waste water released by houses is called Sewage
(c) Dried Sludge is used as manure.
(d) Drains get blocked by Oils and Fats .
2. Water is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.
Ans: Water becomes sewage after use in homes, industries, hospitals etc.
Sewage water contains organic, inorganic impurities, chemicals and germs.
It is harmful to discharge untreated sewage into rivers as it makes water dirty, kills fish and plants living there.
It also leads to spread of diseases.
3. Why should oils and fats not be released in the drains ? Explain.
Ans: Oils and fats should not be released in the drains because they harden and block the drains.
They also clog soil pores in drains and stop water filteration.
4. Describe the steps involved in getting clarified water from waste water.
Ans: Water is clarified by removing physical, chemical and biological matter from it.
The steps involved in getting clarified water are:-
Step 1: Waste water is passed through bar screens to remove large objects.
Step 2: Waste water moved into grit and sand removal tank to remove grit, sand and pebbles.
Step 3: Waste water allowed to settle in another tank which is sloped in middle. Wastes like faeces, oils, grease removed in it.
Step 4: Air is pumped into the water to allow growth of aerobic bacteria. They eat organic wastes in the tank.
Step 5: Water is treated with chlorine or ozone and released into water bodies.
5.What is sludge? Explain how it is treated.
Ans: Sludge is the solid organic wastes like faeces present in the wastewater.
The sludge is removed during water treatment and is decomposed by anaerobic bacteria resulting in formation of biogas.
6. Untreated human excreta is a health hazard. Explain.
Ans: Untreated human excreta is a health hazard as it causes water and soil pollution.
It leads to spread of diseases like cholera, typhoid, polio, dysentery.
7. Name two chemicals used to disinfect water.
Ans: The two chemicals used to disinfect water are Chlorine and Ozone.
8. Explain the function of bar screens in a waste water treatment plant.
Ans: Before the treatment, wastewater is allowed to pass through Bar screens.
Bar screens help in removal of large objects like rags, cans, plastic etc.
9. Explain the relationship between sanitation and disease.
Ans: Sanitation and diseases are interrelated. Poor sanitation leads to soil, water and air pollution which leads to inncrease in the diseases.
Poor sanitation leads to spread of Cholera, typhoid, polio, hepatitis, dysentery.
10. Outline your role as an active citizen in relation to sanitation.
Ans: As active citizens, we should first behave properly ourselves and follow 3R's i.e Reduce, Reuse and Recycle.
We should also motivate people to do same.
We should inform and help municipalities to cover all the open drains and ensure clean sorroundings.
We should ensure that the sewerage system in our locality is properly managed.
Lastly, we should plant more trees and not use polythene and plastic .
11. Here is a crossword puzzle: GoodLuck!
Across
3. Liquid waste products
4 .Solid waste extracted in sewage treatment
6. A word related to hygiene
8. Waste matter discharged from the human body.
Down
1. Used water
2.A pipe carrying sewage
5. Micro-organisms which causes cholera
7. A chemical to disinfect water.
Sol:
12. 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
Ans: (ii) (b)and(c)
13. Tickmark the correct answers.
1. The disease caused by polluted water:
(a) Jaundice (b) Dysentery
(c) Cholera (d) All of these
Ans: (d) All of these
2. Malaria can be triggered by:
(a) Open drains (b) Closed drains
(c) Taps (d) Pipelines
Ans: (a) Open drains
3. Waste that can be broken down by bacteria:
(a) Biological (b) Biochemical
(c) Biodegradable (d) Chemical
Ans: (c) Biodegradable
4. Stage of waste water treatment for removing large particles:
(a) Disinfection (b) Secondary
(c) Primary (d) Chlorination
Ans: (c) Primary .
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