Class 7 Science Chapter 13 Practice Question Answers - Wastewater story

Q1. Untreated human excreta is a:
(a) waste water
(b) health hazard
(c) manure
(d) none of these
Ans: (b)
Untreated human excreta is a health-hazard.

Q2. Which process removes the solids like foeces and other substances from the waste water:
(a) chlorination
(b) decomposition
(c) evaporation
(d) sand and grit removal
Ans: (d)
Sand and grit removal removes the solids from the waste water.

Q3. Excreta from the toilet seats flow through covered drains into a chemicals:
(a) chemicals
(b) biogas plant
(c) vermi-processing toilets
(d) none of these
Ans: (b)
Excreta from the toilet seats flow through covered drains into biogas plant.

Q4. The biogas product is used as a source of:
(a) rains
(b) oils
(c) energy
(d) all of these
Ans: (c)
The biogas product is used as a source of energy.

Q5. What decomposes the sludge:
(a) aerobic bacteria
(b) anaerobic bacteria
(c) both (a) and (b)
(d) none of these
Ans: (b)
An aerobic bacteria decomposes the sludge.

Q6. What helps to clean the clarified water:
(a) aerobic bacteria
(b) anaerobic bacteria
(c) both (a) and (b)
(d) none of these
Ans: (a)
Aerobic bacteria clean the clarified water.

Q7. The instrument used to remove float-able solids from the waste water is:
(a) anemometer
(b) thermometer
(c) skimmer
(d) none of these
Ans: (c)
Skimmer remove the floatable solids from the waste water.

Q8. By which we can prevent drains at our houses from getting choked:
(a) cooking oil and fats should not be thrown down the drain
(b) used tea leaves thrown down the drain
(c) motor oil thrown down the drain
(d) none of these
Ans: (a)
Cooking oil and fats should not be thrown down the drain.

Q9. Different sources of waste water are:
(a) agricultural activities
(b) household activities
(c) industrial activities
(d) all of these
Ans: (d)
All of these activities are the sources of waste water.

Q10. We use water at home to wash clothes and utensils, bathe and flush toilets, it becomes dirty water is called:
(a) drainage
(b) sewage
(c) wastewater
(d) none of these
Ans: (c)
Dirty water called the waste water.

Q11. Which of these disease is not caused by improper disposal of sewage:
(a) cholera
(b) heart attack
(c) jaundice
(d) typhoid
Ans: (b)
Heart attack is not caused by improper disposal of sewage.

Q12. Which of these statements are correct about Ozone:
(a) it is essential for breathing of living organism
(b) it is used to disinfect water
(c) it absorbs ultra voilet rays
(d) its proportion in air is about 3%
Ans: (b)
Ozone is used to disinfect water and absorb ultra violet rays.

Q13. The hyproducts of waste water treatment are:
(a) sludge
(b) biogas
(c) both (a) and (b)
(d) none of these
Ans: (c)
The byproducts of waste water treatment are sludge and biogas.

Q14. Sewage is a:
(a) liquid waste
(b) solid waste
(c) gaseous waste
(d) none of these
Ans: (a)
Sewage is a bquid waste.

Q15. Following process is not a part of waste water treament:
(a) chlorination
(b) decomposition
(c) evaporation
(d) grit and sand removal
Ans: (c)
Evaporation is not a part of waste water treament.

Q16. This disease is not caused by polluted water:
(a) cholera
(b) typhoid
(c) haemorage
(d) hepatitis
Ans: (c)
Haemorage is not caused by polluted water.

Q17. To improve sanitation following new technique is being used:
(a) onsite sewage disposal
(b) vermi processing toilets
(c) sewer system
(d) both (a) and (c)
Ans: (a)
To improve sanitation obsite sewage disposal is being used

Q18. This is not the cause of water pollution:
(a) floods
(b) rains
(c) open defection
(d) chemicals
Ans: (b)
Rains is not the cause of water pollution

Q19. Following should not be disposed off in the drains:
(a) tissue papers
(b) wastewater
(c) oils and fats
(d) excreta
Ans: (c)
Oil and fats should not be disposed off in the drains.

Q20. The suspended impurities in sewage are called:
(a) contaminants
(b) sedimentation
(c) both (a) and (b)
(d) none of these
Ans: (a)
The suspended impurities of sewage are contaminants.

Q21. Full form of WWTP is:
(a) white water treatment plant
(b) waste water treatment plant
(c) both (a) and (b)
(d) none of these
Ans: (b)
Waste water treatment plant is the full form of WWTP.

Q22. The network of big and small pipes carrying waste water are called:
(a) sludge
(b) sullage waste
(c) sewers
(d) all of these
Ans: (c)
Sewers are the network of big and small pipes for waste water.

Q23. Dried sludge is used as:
(a) sludge
(b) sewers
(c) waste water treatment plant
(d) manure
Ans: (d)
Dried sludge is used as manure.

Q24. Drains get blocked by:
(a) chemicals
(b) kitchen waste
(c) both (a) and (b)
(d) none of these
Ans: (c)
Drains get blocked by both (a) and (b) chemicals and kitchen waste.

Q25. The water is taken to grit and sand removal tank where impurities are removed by:
(a) contaminants
(b) sedimentation
(c) both (a) and (b)
(d) none of these
Ans: (b)
Impurities are removed by sedimentation.

Q26. Sludge is collected solid waste from the waste water during the treatment in:
(a) health hazard
(b) white water treatment plant
(c) waste water treatment plant
(d) none of these
Ans: (c)
Sludge is collected solid waste during the waste water treatment plant.

Q27. Chlorine and ozone are used to:
(a) infect water
(b) disinfect water
(c) filtered
(d) none of these
Ans: (b)
Chlorine and Ozone are used to disinfect water.