Free printable worksheet
Class 9 · Water Security · 10 Aug 2026
Which municipal water treatment process involves adding chemicals like alum (aluminum sulfate) to clump together suspended colloidal impurities into heavier flocs?
[1 mark]During water purification, why is aeration performed as one of the preliminary steps?
[2 marks]Match the water source classification in India to its correct characteristic description.
[2 marks]| Column A | Column B |
|---|---|
| 1. Glacial Rivers | a. Fed by melting snow and monsoon rains, ensuring year-round flow |
| 2. Rainfed Tanks | b. Artificial or natural reservoirs filled exclusively during the monsoon season |
| 3. Confined Aquifers | c. Water-bearing strata trapped between impermeable rock layers under pressure |
Answer: __________________________________________
Match each water source or term in Column A with its correct definition or classification in Column B.
[2 marks]| Column A | Column B |
|---|---|
| 1. Inland Water Body | a. Rivers and lakes forming part of surface water |
| 2. Water Table | b. The upper surface of the zone of saturation in groundwater |
| 3. Desalination | c. Process of removing dissolved salts from seawater |
| 4. Rainwater Harvesting | d. Collecting and storing precipitation for direct use |
Answer: __________________________________________
Match each stage of the municipal water supply journey with its primary engineering purpose.
[3 marks]| Column A | Column B |
|---|---|
| 1. Intake Well | a. Draws raw water from a river or reservoir |
| 2. Alum Dosing Tank | b. Coagulates fine suspended particles |
| 3. Rapid Sand Filter | c. Removes remaining fine impurities and bacteria flocs |
| 4. Distribution Mains | d. Transports potable water to residential neighborhoods |
Answer: __________________________________________
The process of adding chlorine compounds to treated drinking water to destroy pathogenic microorganisms is known as _____.
[1 mark]State the primary function of a sluice valve in a municipal water pipeline network.
[1 mark]State the primary function of overhead service reservoirs (water tanks) in an urban water supply network.
[1 mark]Define the term 'potable water' and state one reason why untreated river water in India is generally not considered potable.
[2 marks]Explain why coagulants such as alum (aluminium sulphate) are added during the water treatment process before filtration.
[3 marks]Identify the four main sequential treatment stages in a standard municipal water treatment plant represented in the correct operational order.
[2 marks]