Sewage Treatment

Q.

The process of removal of salt from sea water is called _________(desalination/ salination).

Q. In sewage treatment, decomposition of organic matter is done by _________ . It is the _________ stage treatment of sewage water.

1. sedimentation, primary
2. filtering waste materials, primary
3. frequent agitation of water, secondary
4. chlorination of water, tertiary

Q.

Which of the following is a non-biodegradable pollutant?

1. paper

2. wood

3. DDT

4. cloth

Q.

What happens during the aeration step of water treatment?

1. Amount of oxygen decreases

2. Amount of chlorine decreases

3. Amount of oxygen increases

4. Amount of chlorine increases

Q.

Match the statement in column A with those in column B

Column 1	Column 2
Well water is generally.	Rainwater
Heat is required to melt 1 g of ice at $0°\mathrm{C}$ to water at $0°\mathrm{C}$	Sp.latent heat of fusion
Purest from of natural water	Potable water
Impure form of water	Water pollution
Maximum density of water at $4°\mathrm{C}$	Sedimentation
The process by which suspended impurities in river water settle down.	1gcm-3
The gas used for killing germs in city water	Cholera
Diseases caused by water pollution.	Chlorine
Washing down excessive pesticides and fertilisers into the river water.	Solution
A product formed by dissolving a solute in solvent.	Seawater

Q.

Differentiate between biodegradable and non -biodegradable pollutants.

Q. Which stage of sewage treatment involves the removal of bulkier solid wastes?

1. Quaternary
2. Secondary
3. Primary
4. Tertiary

Q. In which stage is the liquid sewage treated with chemical disinfectants?
(a) primary treatment
(b) secondary treatment
(c) biological treatment
(d) tertiary treatment