Available Answers

1. 1.

   Fill in the blanks.

   1. The system that carries the sewage from the point where it is produced to the point of disposal is called _______________.
   2. The residue in the water treatment plants can be used as _______________.
   3. Chlorine when added to water kills _______________.
   4. Primary treatment of water is a _______________ process.
   5. _______________ sewage system is the sewage system used in the aeroplanes.
2. 2.

   Give one word for each.

   1. Water we get before biological treatment
   2. Water we get after the chemical treatment
   3. The sludge is processed in these large tanks
   4. The network system that carries the sewage
3. 3.

   What is sewage? What is sewerage?

4. 4.

   What are the harmful substances present in the sewage?

5. 5.

   Why treatment of water is essential?

6. 6.

   What are the types of impurities present in the wastewater?