Q1. 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_________.

 

Q2. True/False

                           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. _________

 

Q3. Which day is celebrated as World Water Day?

 

Q4. Name two chemicals used to disinfect water.

 

Q5. What is sewerage?

 

Q6. Why chemicals should not be thrown down the drain?

 

Q7. What are the reasons for scarcity of freshwater?

 

Q8. What is waste water?

 

Q9. What are the harmful effects of drinking contaminated water?



Q10. What causes blockage of the drain?

 

Q11. Why air is pumped into clarified water?

 

Q12. Why should eucalyptus trees be planted along sewage ponds?

 

Q13. Write two uses of ozone.

 

Q14. Why are bacteria important in sewage treatment?

 

Q15. What is cleaning of water?

 

Q16. Why should oils and fats be not released in the drain? Explain.

 

Last modified: Tuesday, 8 January 2019, 11:58 PM