CBSE Class 7 Science Waste Water Story Worksheet

WASTE WATER STORY 

3- Match The Column:-

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Q1. Name two useful substances which are produced by the treatment of sewage. State their use

Q2. Explain why stagnant sewage causes disease?

Q3. Why discharge of untreated sewage into water bodies undesirable?

Q4. Why do fishes die due to excessive water pollution?

Q5. Why are manholes made?

Q6. At a sewage treatment plant, what type of bacteria work in

a) in the digester tank

b) in the aeration tank

Q7. Name two things that can be made from sludge extracted during the treatment of sewage.

Q8. Why should oils & fats not be released in drains?

Q9. Why should chemicals not be released in the drain?

Q10. Why should used tea leaves, solid food remains etc not be released in the drain?

Q11. What is waste water? Can it be recycled?

Q12. What are the sources of waste water?

Q13. What is activated sludge?

Q14. Name a chemical used to further treat clarified water.

Q15. Good sanitation practices yield good hygiene. Explain.

Q16.What is a septic tank?How does it work?

Q17.Name any two low cost, onsite sewage disposal system for human waste.

Q18. What is a cause of a large number of diseasers in our country?

Q19. What is the purpose of bubbling air into the aeration tank during the treatment of sewage?

Q20. What are the floating impurities in the swewage? How are they removed?

1.Waste water which flows from homes into drains is called-
(A) Sewage.
(B) Effluent.
(C) Emission.
(D) Sludge.

2.Materials thatare of no use before recyclingare called-
(A) Waste.
(B) Goods.
(C) Pollution.
(D) None of these.

3.Underground pipes that carry waste water are called-
(A) Sewers.
(B) Effluent.
(C) Tank.
(D) Compost.

4.Sludge is used as-
(A) Fertiliser.
(B) Insecticide.
(C) Pesticide.
(D) Food.

5.Malaria can be triggered by-
(A) Open drains.
(B) Closed drains.
(C) Taps.
(D) Pipelines.

6.Which of the following is the stage of wastewater treatment for removing large particles?
(A) Disinfection.
(B) Secondary.
(C) Primary.
(D) Chlorination.

7.What is waste water ?

8.Name theinorganic impurities presentinwaste water?

9.Name the organic impurities presentin waste water?

10.Which instrument removes the solids like faeces and other substances from the waste water?

11.Name 2 diseases caused by micro-organisms present in sewage.

12.What is the function of skimmer in waste water treatment plant?

13.Which chemicals are used to disinfect water?

14.Who decomposes the sludge?

15.What is the use of bar screens in a waste water treatment plant?

16.What are contaminants?

17.Name 2 bacterial diseases.

18.Name 2 techniques which are used to improve sanitation?

19.Name the byproducts of waste water treatment.

20.In sewage, nitrates and phosphates are-
(A) Organic impurities.
(B) Inorganic impurities.
(C) Both of them.
(D) None of them.

21.Disinfection is the..................... step of wastewater treatment.
(A) last
(B) first
(C) second last
(D) None of these.

22.Dissolved or suspended impurities present in sewage are called-
(A) Sludge.
(B) Effluent.
(C) Contaminants.
(D) None of these.

23.Sullage water is a type of-
(A) Liquid.
(B) Liquid waste.
(C) Sewage.
(D) None of these.

24.Network of pipes through which sewage flows is called-
(A) Sewerage.
(B) Sewer.
(C) Pipeline.
(D) None of these.

25.WWTP is-
(A) Waste Water Treatment Process.
(B) Waste Water Treatment Plant.
(C) Waste Water Treatment Principle.
(D) None of them.

26.Toilet water is a kind of .................... .
(A) Sewage.
(B) Agricultural waste water.
(C) Industrial waste water.
(D) Both (a) and (b).

27.A toilet in which human excreta is treated by earthworms is called-
(A) Vermi-composting toilet.
(B) Vermi-processing toilet.
(C) Vermi-treated toilet.
(D) None of these.

28.The fertilisers and pesticides sprayed on crops go in-
(A) Effluent.
(B) Sewage.
(C) Agricultural waste water.
(D) Sludge.

29.Industrial and commercial organisations produce-
(A) Foul waste.
(B) Trade waste.
(C) Sullage water.
(D) None of them.

30.Secondary treatment is also called-
(A) Chemical treatment.
(B) Mechanical treatment.
(C) Biological treatment.
(D) None of these.

31...................... refers to the solids accumulated from primary and secondary treatment.
(A) Sewage
(B) Sludge
(C) Garbage
(D) Manure

32.Sewage is a kind of-
(A) Agricultural waste.
(B) Liquid waste.
(C) Mining waste.
(D) Gaseous waste.

33.Wastewater generated from houses is commonly called-
(A) Sludge.
(B) Sewage.
(C) Effluent.
(D) None of these.

34.Tertiary treatment is a .................... process.
(A) biological
(B) mechanical
(C) chemical
(D) physical

35.Waste that can be broken down by bacteria is-
(A) Biological.
(B) Biochemical.
(C) Biodegradable.
(D) Chemical.

36.Disinfection of water is done by-
(A) Chlorine.
(B) Ozone.
(C) UV radiation.
(D) All of these.

37.The disease caused by polluted water is-
(A) Jaundice.
(B) Dysentery.
(C) Cholera.
(D) All of these.

38.Waste water discharged from the factories is called-
(A) Industrial sewage.
(B) Industrial sludge.
(C) Industrial effluent.
(D) Industrial emission.

39.Chlorine is used in municipal water treatment to-
(A) Increase the taste of water.
(B) Prevent evaporation.
(C) Kill the harmful micro-organisms.
(D) Prevent sedimentation.

40.Solid matter separated from sewage is used-
(A) As food.
(B) As polymers.
(C) To generate biogas.
(D) To prepare higher polymers.

41.Which of the following processes are employed in the purification of water in a municipal water treatment system?
(A) Sedimentation, sublimation and filtration.
(B) Sublimation, evaporation and filtration.
(C) Sedimentation, distillation and sublimation.
(D) Sedimentation, filtration and chlorination.

42.Which of the following is used to kill the micro-organisms present in water?
(A) Iodine.
(B) Sodium.
(C) Chlorine.
(D) Calcium.

43.Bacteria present in sewage can cause-
(A) Cholera.
(B) T.B.
(C) AIDS.
(D) Malaria.

44.Why are eucalyptus trees planted along the sewage ponds?

45.Why should we not throw chemicals into the drains?

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46.What do you mean by sewage. Why untreated sewage should not be discharged into rivers or seas?

47.What do you understand by sludge? How is it treated?

48.Why should oils and fats not be discharged in the drain?

49.What do you understand by sewerage system?

50.What is clarified water?

51.Which problems arise due to open drain system?

52.What do you understand by "Sewage Treatment"?

53.Explain why untreated human excreta is a health hazard?

54.What is the relationship between sanitation and disease?

I. Fill in the blanks :

1. Waste water is treated in a ________________.

2. The sludge is decomposed by ____________ bacteria.

3. _____________ and contaminated drinking water is the cause of a large number of diseases.

4. The process of waste water treatment is known as _______________.

5. Sewage is a _____________________ waste.

6. The activated sludge is about _____________ % water.

7. The suspended impurities dissolved in swage are called ______________.

II Name the following :

1. The nutrient present in sewage.

2. By products of waste water treatment.

3. A plant which can absorb waste water rapidly and release pure water vapour to the atmosphere.

4. Solid waste extracted in sewage treatment.

5. Any two water borne disease.

6. Expand WWTP.

III State whether True or False :

1. Urea is an inorganic impurity present in sewage.

2. Sewerage is a transport system that carries sewage to the treatment plant.

3. Chemical toilet is a low cost onsite sewage disposal system.

4. Sewage is solid waste which causes water and soil pollution.

5. Untreated human excreta is a health hazard.

Q1) What is meant by waste water?

Q2) What is sewage? What does it contain?

Q3) Name two organic and inorganic impurities present in sewage.

Q4) Fill in the blanks:-

        a. The impurities present in wastewater are called____________.

        b. The World Water Day is celebrated every year on __________.

        c. The activated sludge is about __________% water.

        d. Water is disinfected by using chemicals like __________ and __________.

        e. __________ and __________ are water borne diseases.

        f. Dried sludge is used as _______________.

Q5) Name the processes involved in the treatment of waste water.

Q6) What is the function of the bar screen used in a Wastewater Treatment Plant?

Q7) What is sludge? What are its uses?

Q8) What is clarified water? Explain.

Q9) Differentiate between aerobic and anaerobic bacteria?

Q10) Give reasons
a. Eucalyptus trees are grown all along sewage ponds.
b. Used tea leaves, solid food remains, cotton etc. should be thrown in the dustbin.
c. Large amount of waste generated at public places must be disposed off properly.
d. Untreated human excreta is a health hazard.

Q11) Write a short note on “vermiprocessing toilet”.

Q12) What can we do to reduce the load of pollutants in waste water and the pressure on Wastewater Treatment Plant?

Q13) Padma’s village was facing a lot of problem with the sewage disposal. The environment was becoming unhealthy and unhygienic. Padma and her friends decided to talk to the village chief and find a solution for this problem. What values does the approach of Padma and her friends reflect?