Which one of the following impurities is easiest to remove from waste water?
Bacteria
Colloids
Dissolved solids
Suspended solids
Which one of the following diseases is not due to contamination of water?
Hepatitis-B
Jaundice
Cholera
Typhoid
Nuisance growth of aquatic plants and bloom-forming algae in natural water is generally due to high concentrations of
carbon
sulphur
calcium
phosphorus
Algal blooms impart a distinct colour to water due to
their pigments
excretion of coloured substances
formation of coloured chemicals in water facilitated by physiological degradation of algae
absorption of light by algal cell wall
Match the items in column I and column II and choose the correct option.
| Column I | Column II | ||
|---|---|---|---|
| A. | UV | 1. | Biomagnificatron |
| B. | Biodegradable organic matter | 2. | Eutrophication |
| C. | DDT | 3. | Snow blindness |
| D. | Phosphates | 4. | BOD |
$$ \text { The correct matches is } $$
A B C D
$2 \,\quad \,1 \quad \,4 \quad\, 3$
A B C D
$3 \quad 2 \quad 4 \quad 1$
A B C D
$3 \quad 4 \quad 1 \quad 2$
A B C D
$3 \quad 1 \quad 4 \quad 2$