Class 7 Science - Chapter Wastewater Story NCERT Solutions | Describe the steps involved in getting c
Describe the steps involved in getting clarified water from wastewater.
We need water for all our as usual activities. Each and every process is in connection to the water that we use. Now a days, we waste water too much. Water conservation is not being done properly. So water is clarified from the wastewater (also known as sewage) generated by various activities like washing, laundries and etc.
Clarified water from wastewater:
Wastewater is collected and passed through bar screens where plastic bags, sticks, cans, napkins etc. are removed. This water then enters a grit and a sand removal tank.
The speed of the water is decreased so that the sand particles get settled at the bottom of the tank. After this, the water is allowed to settle in a large tank which is tilted towards the centre.
Solid wastes are settled and removal by the scraper and which is known as clarified water. Air is pumped in this water to help aerobic bacteria to grow.
The bacteria consume the wastes by microbial action. These microbes settle down after several hours and the water at the top is removed.
This water is discharged into rivers and oceans or is put to other uses. Nature cleans it up further. Sometimes it may be necessary to disinfect water with chemicals like chlorine and ozone before releasing it into the distribution system.
More Questions From Class 7 Science - Chapter Wastewater Story
- Q:-
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 bodyDown
1. Used water
2. A pipe carrying sewage
5. Micro-organisms which causes cholera
7. A chemical to disinfect water - Q:-
Why should oils and fats be not released in the drain? Explain.
- Q:-
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 - Q:-
Explain the relationship between sanitation and disease.
- Q:-
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 ____________. - Q:-
What is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.
- Q:-
Explain the function of bar screens in a wastewater treatment plant.
- Q:-
Outline your role as an active citizen in relation to sanitation.
- Q:-
Name two chemicals used to disinfect water.
- Q:-
What is sludge? Explain how it is treated.
Popular Questions of Class 7 Science
- Q:-
State similarities and differences between the laboratory thermometer and the clinical thermometer.
- Q:-
State differences between acids and bases.
- Q:-
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food - Q:-
Name the elements that determine the weather of a place.
- Q:-
Fill the missing word in the blank spaces in the following statements:
(a) Wind is——————air.
(b) Winds are generated due to —————— heating on the earth.
(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.
(d) Air moves from a region of ——— pressure to a region of ———. - Q:-
In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants - Q:-
Why does an athlete breathe faster and deeper than usual after finishing the race?
- Q:-
Match structures given in Column I with functions given in Column II.
Column I Column II
(i) Stomata (a) Absorption of water
(ii) Xylem (b) Transpiration
(iii) Root hairs (c) Transport of food
(iv) Phloem (d) Transport of water
(e) Synthesis of carbohydrates - Q:-
Fill in the blanks:
(a) Production of new individuals from the vegetative part of parent is called_____________.
(b) A flower may have either male or female reproductive parts. Such a flower is called_____________.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as _____________.
(d) The fusion of male and female gametes is termed as _____________.
(e) Seed dispersal takes place by means of _____________, _____________ and _____________. - Q:-
Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge.
Recently Viewed Questions of Class 7 Science
- Q:-
Fill in the blank:
(a) The insects, butterflies, honeybees and birds help flowering plants in .
(b) A forest is a purifier of and .
(c) Herbs form the layer in the forest .
(d) The decaying leaves and animal droppings in a forest enrich the . - Q:-
Solve the following crossword puzzle with the clues given:
Across
2. Plantation prevents it.
5. Use should be banned to avoid soil pollution.
6. Type of soil used for making pottery.
7. Living organism in the soil.Down
1. In desert soil erosion occurs through.
3. Clay and loam are suitable for cereals like.
4. This type of soil can hold very little water.
5. Collective name for layers of soil. - Q:-
Is the distilled water acidic/basic/neutral? How would you verify it?
- Q:-
Fill in the blanks:
(a) An image that cannot be obtained on a screen is called ____________.
(b) Image formed by a convex __________ is always virtual and smaller in size.
(c) An image formed by a __________ mirror is always of the same size as that of the object.
(d) An image which can be obtained on a screen is called a _________ image.
(e) An image formed by a concave ___________ cannot be obtained on a screen. - Q:-
In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants - Q:-
State differences between acids and bases.
- Q:-
Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.
(i) Process – A is a chemical change.
(ii) Process – B is a chemical change. (iii) Both processes A and B are chemical changes.
(iv) None of these processes is a chemical change. - Q:-
Fill the missing word in the blank spaces in the following statements:
(a) Wind is——————air.
(b) Winds are generated due to —————— heating on the earth.
(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.
(d) Air moves from a region of ——— pressure to a region of ———. - Q:-
Explain why burning of wood and cutting it into small pieces are considered as two different types of changes.
- Q:-
Describe the function of the heart.
- All Chapters Of Class 7 Science
- All Subjects Of Class 7