Environmental Engineering problems
- 1. Operating principle of cyclone separator is based on the action of __________ dust particles.
Options- A. diffusion of
- B. centrifugal force on
- C. gravitational force on
- D. electrostatic force on Discuss
Correct Answer: centrifugal force on
- 2. Coal washing waste water containing about 3% suspended solids (comprising of clay, slate, stone etc.) is treated for solid particles removal
Options- A. by chemical coagulation.
- B. in sedimentation tanks equipped with mechanical scrapper.
- C. in vacuum filter.
- D. in clarifiers. Discuss
Correct Answer: in sedimentation tanks equipped with mechanical scrapper.
- 3. The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the
Options- A. bacterial stability factor.
- B. relative stability.
- C. biological oxygen demand (BOD).
- D. oxygen ion concentration. Discuss
Correct Answer: relative stability.
- 4. Scale formation in boiler is controlled by
Options- 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. Discuss
Correct Answer: reduction in hardness, silica & alumina in feed water.
- 5. Most of the atmospheric air pollutants are present in large quantity in
Options- A. stratosphere
- B. thermosphere
- C. trophosphere
- D. mesosphere Discuss
Correct Answer: trophosphere
- 6. Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by
Options- A. natural aeration of water stream.
- B. photosynthetic action of algae.
- C. both (a) & (b).
- D. neither (a) nor (b). Discuss
Correct Answer: both (a) & (b).
- 7. H2S present in gaseous stream can be removed by adsorption on
Options- A. silica gel
- B. active carbon
- C. bog iron
- D. limestone powder Discuss
Correct Answer: bog iron
- 8. Aerobic biological oxidation ponds used for the purification of polluted water
Options- A. destroys/removes pathogen from the sewage.
- B. is not very effective for nonbiodegradable substances (e.g. ABS) containing effluents.
- C. destroys/removes pathogen much more effectively if the sewage is chlorinated.
- D. all (a), (b) & (c). Discuss
Correct Answer: all (a), (b) & (c).
- 9. Polluted water having low BOD are most economically treated in
Options- A. sedimentation tanks
- B. oxidation ponds
- C. sludge digester
- D. clarifier Discuss
Correct Answer: oxidation ponds
- 10. Dust collection efficiency of a cyclone separator depends upon its
Options- A. diameter.
- B. inlet gas velocity.
- C. overall height.
- D. all (a), (b) & (c). Discuss
Correct Answer: all (a), (b) & (c).
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