Sewage is the wastewater produced by human activities from homes, industries etc. Untreated sewage should not be discharged into the sea because it contains pollutants and harmful microorganisms that will contaminate water and cause disease in people who use it.
Every citizen is responsible for ensuring proper sanitation. The following are the steps we should take to play an active role.
- Maintain the cleanliness of our surroundings.
- The house’s sewage system should be properly managed.
- In the event of a sewage pipe leak, immediately notify the appropriate authority.
Download PDF of Class 7 Chemistry Worksheet on Chapter 18 Wastewater Story – Set 3
CBSE Class 7 Chemistry Worksheet Chapter 18 Wastewater Story – Set 3
Q1. The by-products of the sewage treatment plant is/are _____.
a.) Sludge
b.) Biogas
c.) Manure
d.) All of the above
Q2. Oil should not be discarded through drain pipes because ______.
a.) It does not allow bacteria to decompose
b.) It blocks the drainage pipes
c.) It does not allow free flow of oxygen
d.) It causes diseases
Q3. The low-cost on-site sewage disposal system is ______.
a.) Chemical toilets
b.) Septic tank
c.) Vermicomposting pit
d.) All of the above
Q4. The liquid waste that has dissolved suspended impurities is ______.
a.) Sludge
b.) Biogas
c.) Wastewater
d.) Potable water
Q5. Which of the following is used as a disinfectant?
a.) Ozone
b.) Magnesium
c.) Zinc
d.) Chlorine
Q6. Fill in the blanks.
a.) ____ from the treatment plant can be used to make manure.
b.) Drains get blocked by ___ and ___.
c.) Suspended impurities contained by sewage are called ____.
Q7. State True or False.
a.) Bar screens help in removing pebbles and other solid impurities in the wastewater treatment plant.
b.) The process of treatment of wastewater is sewage treatment.
c.) Open drains should not be covered.
Q8. Why is sanitation important?
Q9. Define contaminants.
Q10. Why can’t seawater be used for drinking purposes?
Q11. Name two things that can be made from sludge extracted during the treatment of sewage.
Q12. Why is it harmful to discharge untreated sewage into rivers or seas?
Q13. Differentiate between clarified water and wastewater.
Q14. Explain how sludge is treated.
Q15. List some practices by which you can manage wastewater at your homes.
Q16. What is a vermi-processing toilet?
Q17. Discuss the biological and chemical processes in the sewage water treatment plant.
Q18. Why is untreated human excreta a health hazard?
Q19. What do you mean by sewage, sewers and sewerage?
Q20. What is the physical process of cleaning wastewater in a wastewater treatment plant?
Download PDF to access answers of Chemistry Worksheet for Class 7 Chemistry Chapter 18 Wastewater Story Set 3.
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