Topic outline

    • Wastewater Story

      Q1. Fill in the blanks.

                                   i.        Cleaning of water is a process of removing pollutants.

                                  ii.        Wastewater released by houses is called sewage.

                                 iii.        Dried sludge is used as manure.

                                 iv.        Drains get blocked by cooking oil and fats.

                                  v.        By-products of wastewater treatment are sludge and biogas.


      Q2. True/False

                                i.        Clean water is a basic need of human being. True

                               ii.        Used water is clean water. False

                              iii.        Treatment plants reduce pollutants in wastewater to a level where nature can take care of it. True

                              iv.        Open drain system is a breeding place for flies, mosquitoes and organisms which cause diseases. True

                               v.        People should defecate in the open. False

      Q3. Which day is celebrated as World Water Day?

      Ans. 22 March


      Q4. Name two chemicals used to disinfect water.

      Ans. Two chemicals used to disinfect water are chlorine and ozone.


      Q5. What is sewerage?

      Ans. It is like a transport system that carries sewage from the point of being produced to the point of disposal, i.e. treatment plant.


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

      Ans. Chemicals should not be thrown down the drain because chemicals like paints, solvents, insecticides, motor oil and medicines may kill microbes that help purify water.

      Q7. What are the reasons for scarcity of freshwater?

      Ans. There is scarcity of freshwater due to population growth, pollution, industrial development, mismanagement and other factors.


      Q8. What is waste water?

      Ans. Rich in lather, mixed with oil, black– brown water that goes down the drains from sinks, showers, toilets, laundries is dirty. It is called wastewater.


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

      Ans. Contaminated drinking water is the cause of a large number of diseases such as cholera, typhoid, polio, meningitis, hepatitis and dysentery.


      Q10. What causes blockage of the drain?

      Ans. Used tealeaves, solid food remains, soft toys, cotton, sanitary towels, etc. should be thrown in the dustbin. These wastes cause blockage of the drain.


      Q11. Why air is pumped into clarified water?

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

      Bacteria consume human waste, food waste, soaps and other unwanted matter still remaining in clarified water.


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

      Ans. It has been suggested that we should plant eucalyptus trees all along sewage ponds. These trees absorb all surplus wastewater rapidly and release pure water vapour into the atmosphere.

      Q13. Write two uses of ozone.

      Ans. Two uses of ozone are:

                               i.        It is used to disinfect water.

                              ii.        It absorbs ultraviolet rays.


      Q14. Why are bacteria important in sewage treatment?

      Ans.  Bacteria are important in sewage treatment because it consume human waste, food waste, soaps and other unwanted matter still remaining in clarified water.


      Q15. What is cleaning of water?

      Ans. Cleaning of water is a process of removing pollutants before it enters a water body or is reused. This process of wastewater treatment is commonly known as “Sewage Treatment”.


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

      Ans. Oils and fats should not be released in the drain because they can harden and block the pipes. In an open drain the fats clog the soil pores reducing its effectiveness in filtering water.

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