Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes_______________?

A. Foaming
B. Odour nuisances
C. Undesirable plant growth
D. Turbidity

TLV of lead for public sewer/waste water is about ______________ ppm?

A. 1
B. 25
C. 150
D. 650

Which of the following is a secondary air pollutant ?

A. Photochemical smog
B. Sulphur dioxide
C. Nitrogen dioxide
D. Dust particles

Ozone is__________________?

A. A primary pollutant
B. A secondary pollutant
C. Impervious to ultra-violet rays
D. Both B. and C.

Infective bacteria in water is killed by the _____________ process?

A. Sterilisation
B. Aeration
C. Disinfection
D. None of these

Hydrogen ion concentration in distilled water is___________________?

A. 10-7
B. 7 × 10-7
C. 107
D. 7 × 107

The progressive warming up of the earth’s surface is mainly due to the___________________?

A. Automobile exhaust
B. Blanketing effect of CO2 in the atmosphere
C. De-forestation
D. Thickening of ozone layer

TLV of NO2 & NO exposure for the human being is 5 & 25 ppm respectively. Prolonged exposure of human being to NO2 causes_________________?

A. Skin disorder
B. Bronchitis
C. Bone disease
D. Cancer

The density of the gases (present in air) decreases with increasing altitude to such an extent, that about 70% of the mass of atmospheric air is found in the lower 5 km. of the atmosphere. This lower region of atmosphere is called the_________________?

A. Ionosphere
B. Troposphere
C. Stratosphere
D. None of these

Which of the following processes is involved in the biochemical treatment of sewage effluents ?

A. Oxidation
B. Reduction
C. Dehydration
D. Fermentation