ENVIRONMENTAL POLLUTION & CONTROL MCQS 29

ENVIRONMENTAL POLLUTION & CONTROL  MCQS 29

1. Radioactive substances present in the polluted water stream can be removed by
(A) Biological oxygen treatment
(B) Coagulation and filtration
(C) Adsorption in ion exchange materials
(D) None of these
Answer: Option C
2. Iron & manganese present in the polluted water is removed by
(A) Simple filtration
(B) Oxidation followed by settling & filtration
(C) Chemical coagulation
(D) Chlorination only
Answer: Option B

3. TLV of ozone (O3) and phosgene (COCl2) in air is __________ ppm.
(A) 0.1 (B) 25 (C) 100 (D) 1000
Answer: Option A

4. BOD of raw municipal sewage may be in the range of about __________ mg/litre.
(A) 1-2
(B) 5-10 
(C) 150-300
(D) 2000-3000
Answer: Option C

5. Presence of bacteria in potable (drinking) water causes
(A) Turbidity
(B) Disease
(C) Bad odour
(D) Bad taste & colour
Answer: Option B

6. Tolerable limit of nitrogen oxides in air is __________ ppm.
(A) 0.1
(B) 1
(C) 5
(D) 25
Answer: Option C

7. Noise level heard at a distance of about 100 metres from a jet engine with after burner is
about __________ decibels.
(A) 120
(B) 140
(C) 170
(D) 200
Answer: Option C

8. Presence of __________ in water stream are deleterious to aquatic life.
(A) Soluble and toxic organics
(B) Suspended solids
(C) Heavy metals and cyanides
(D) All (A), (B) & (C)
Answer: Option D

9. Scale formation in boiler is controlled by
(A) Preheating of feed water
(B) Reduction in hardness, silica & alumina in feed water
(C) Keeping the pH value of feed water just below 7
(D) Eliminating H2S in feed water
Answer: Option B

10. Noise emitted by a ventilation fan at a distance of 3 metres is about __________ decibels.
(A) 85
(B) 105
(C) 125
(D) 145
Answer: Option B

11. Main pollutant present in automobile exhaust is
(A) CO
(B) CO2
(C) NO
(D) Hydrocarbons
Answer: Option A

12. The main pollutant in waste water discharged from a petroleum refinery is oil (both in free
and emulsified form). Free oil is removed by
(A) Biological oxygen pond
(B) Aerated lagoons
(C) Trickling filters
(D) Gravity separator having oil skimming devices
Answer: Option D