Very Short Question Answers - Waste Water Story Class 7 Notes | EduRev

Science Class 7

Created by: Praveen Kumar

Class 7 : Very Short Question Answers - Waste Water Story Class 7 Notes | EduRev

The document Very Short Question Answers - Waste Water Story Class 7 Notes | EduRev is a part of the Class 7 Course Science Class 7.
All you need of Class 7 at this link: Class 7

Very Short Q & A :


Q1: What is sewage?

Ans : Waste water released by houses is called sewage.


Q2: What per cent of earth’s water is fresh?

Ans : 3 per cent.


Q3: What constitutes waste water?

Ans : It can include human waste, food scraps and chemicals.


Q4: State one of the reasons for increasing scarcity of fresh water.

Ans : Population growth.


Q5: Which day is celebrated as World Water Day?

Ans : 22 March


Q6: What is cleaning of water?

Ans : Cleaning of water is the process of removing pollutants before it enters a water body or is reused.


Q7: In order to have safe drinking water, it should be ________.

Ans : Boiled


Q8: What are the adverse effects of drinking contaminated water?

Ans : Drinking contaminated water results in diseases such as cholera, typhoid and diarrhoea. Polluted water can also prove fatal.


Q9: Water gets contaminated and scarcity of clean water is due to :

  • People take baths and wash clothes in rivers and lakes.
  • Many people bathe their animals in rivers and lakes.
  • Increase in the population, industries and improper disposal of waste
  • All of the above.

Ans : All of the above.


Q10: What is sewage treatment?

Ans : Pollutants in waste water can be removed in several stages, and this process is called “sewage treatment.


Q11: Sewage contains organic and _______________ impurities.

Ans : Inorganic


Q12: Sewage contains disease-causing bacteria. True/False

Ans : True


Q13: Saprotrophic bacteria feed on dead organisms.True/False

Ans : True


Q14: Sewage contains some harmful nutrients, such as ______________and nitrogen.

Ans : Phosphorous


Q15: Wastewater has many impurities and these impurities should be removed by _______________.

Ans : Water treatment.


Q16: What is the purpose of filtering waste water?

Ans : To remove large impurities.


Q17: What is a clarifier?

Ans : A clarifier is a tank with its central part inclined downwards so as to allow faeces to settle down. The inclined waste is then removed using a scraper.


Q18: Name some biological contaminants in water.

Ans : bacteria and microbes


Q19: Name the chemical used in water plant to clean water

Ans : Chlorine tablets or ozone.


Q20: Dried _ is used as manure.

Ans : Sludge


Q21: List the substances responsible for blockage of drain.

Ans : Tealeaves, solid food remains, soft toys, cotton, and sanitary towels.


Q22: Why should used tea leaves, solid food remains, etc. not be released in 

the drains?

Ans : Used tea leaves, solid food remains etc. should not be thrown down the drain as they may choke the drain.


Q23: What is the function of bar screens in waste water treatment plant?

Ans : The bar screen remove the large objects like rags, sticks, cans, plastics packets etc. from the sewage.


Q24: Why waste water is passed through bar screen?

Ans : Waste water is passed through bar screens to remove big objects like cans, sticks, rags etc.


Q25: What is the function of a skimmer?

Ans : A skimmer removes the floatable solids like oil, grease etc.


Q26: Why air is pumped into clarified water?

Ans : Air is pumped into clarified water to help aerobic bacteria to grow.


Q27: The suspended microbes in water treatment plant settle at the __________& the water is removed from the_____

Ans : Bottom and top.


Q28: State various uses of water.

Ans : Water is used for:

  • Drinking
  • Cooking
  • Washing clothes, utensils
  • Generating electricity
  • Bathing


Q29: What is the actual reason behind improper sanitation?

Ans : Lack of knowledge and of money, illiteracy, large population and lack of social awareness results in improper sanitation


Q30: Onsite sewage disposal systems collect human excreta and store it in a hole or a pipe, and later direct it to a sewage treatment plant. True/False.

Ans : True


Q31: Septic tanks are not suitable for places such as hospitals, isolated buildings and clusters of houses where there is no sewage.True/False

Ans : False


Q32: What kind of toilets are in aeroplanes and trains?

Ans : Chemical toilets


Q33: Public places such as railway stations, bus depots, airports and hospitals generate a lot of waste, which leads to diseases. True/False.

Ans : True


Q34: Solids like faeces settle at the bottom by _____________ and are removed with a scraper.

Ans : Sedimentation

Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

Complete Syllabus of Class 7

Dynamic Test

Content Category

Related Searches

Semester Notes

,

Very Short Question Answers - Waste Water Story Class 7 Notes | EduRev

,

Extra Questions

,

shortcuts and tricks

,

video lectures

,

Exam

,

pdf

,

MCQs

,

practice quizzes

,

Summary

,

study material

,

Sample Paper

,

Very Short Question Answers - Waste Water Story Class 7 Notes | EduRev

,

Important questions

,

ppt

,

Very Short Question Answers - Waste Water Story Class 7 Notes | EduRev

,

Previous Year Questions with Solutions

,

Objective type Questions

,

Free

,

past year papers

,

mock tests for examination

,

Viva Questions

;