What is sludge? Explain how it is treated.
Sludge is the collected solid waste from the wastewater during the treatment in water treatment plant. Sludge is decomposed in a separate tank by the anaerobic bacteria. Activated sludge is used as manure.
What is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.
Fill in the blanks:
(a) Cleaning of water is process of removing __________
(b) Wastewater released by houses is called __________.
(c) Dried __________ is used as manure.
(d) Drains get blocked by __________ and __________.
Here is a crossword puzzle. Good luck!
Across:
3. Liquid waste products
4. Solid waste extracted in sewage treatment
6. A word related to hygiene
8. Waste matter discharged from human body
Down:
1. Used water
2. A pipe carrying sewage
5. Micro-organisms which cause cholera
7. A chemical to disinfect water