Wastewater story Class 7 Worksheet Science Chapter 13

Q.1.  Fill in the blanks.
(i) Cleaning of water is a process of removing _______ .
(ii) Wastewater released by houses is called ______.
(iii) Dried ____ is used as manure.
(iv) Drains get blocked by ____ and ____.
(v) By-products of wastewater treatment are ____ and ____ .

Q.2. State True (T) or False (F).

(i) Clean water is a basic need of human being.
(ii) Used water is clean water.
(iii) Treatment plants reduce pollutants in wastewater to a level where nature can take care of it.
(iv) Open drain system is a breeding place for flies, mosquitoes and organisms which cause diseases.
(v) People should defecate in the open.

Q.3.  Name two chemicals used to disinfect water.

Q.4. What is sewerage?

Q.5. Which day is celebrated as World Water Day?

Q.6. Why chemicals should not be thrown down the drain?

Q.7. What is waste water?

Q.8. What causes blockage of the drain?

Q.9. What are the reasons for scarcity of freshwater?

Q.10. What are the harmful effects of drinking contaminated water?

Q.11. Why air is pumped into clarified water?

Q.12. Why should eucalyptus trees be planted along sewage ponds?

Q.13. Why are bacteria important in sewage treatment?

Q.14. Why should oils and fats be not released in the drain? Explain.

Q.15. Write two uses of ozone

Q.16. What is cleaning of water?

Q.17. What is sewage treatment?

Q.18. Outline your role as an active citizen in relation to sanitation.

Q.19. How can we contribute in maintaining sanitation at public places?

Q.20. Explain the function of bar screens in a wastewater treatment plant.

You can find Worksheets Solutions here: Worksheet Solutions: Wastewater story