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.
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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:-
Given below is a crossword puzzle based on this lesson. Use hints to fill in the blank spaces with letters that complete the words.
Down Across
(D) 1 : Thorough washing (A) 1 : Keeps warm
2 : Animal fibre 2 : Its leaves are eaten by silkworms
3 : Long thread like structure 3 : Hatches from egg of moth
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Sketch the cross section of soil and label the various layers.
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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:-
Take three test-tubes. Fill æth of each with water. Label them A, B and C. Keep a snail in test-tube A, a water plant in test-tube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of CO2?
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Sketch the reproductive parts of a flower.
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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:-
Describe how crystals of copper sulphate are prepared.
- Q:-
Match the items in Column I with those in Column II:
Column I Column II
(i) A home for living organisms (a) Large particles
(ii) Upper layer of the soil (b) All kinds of soil
(iii) Sandy soil (c) Dark in colour
(iv) Middle layer of the soil (d) Small particles and packed tight (v) Clayey soil (e) Lesser amount of humus - Q:-
When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
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You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answer.
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Match the words of Column I with those given in Column II:
Column I Column II
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2. Mulberry leaves (b) Wool yielding animal
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4. Cocoon (d) Reeling
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Make a sketch showing groundwater and water table. Label it.
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Fill in the blanks :
(a) The hotness of an object is determined by its __________.
(b) Temperature of boiling water cannot be measured by a _____________ thermometer.
(c) Temperature is measured in degree ______________.(d) No medium is required for transfer of heat by the process of __________.
(e) A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of ______________.
(f ) Clothes of ______________ colours absorb heat better than clothes of light colours.
- NCERT Chapter