Engineering Questions with Answers - Multiple Choice Questions

Environmental Engineering MCQ – Disposal of Sewage

1 - Question

Which of the following is a prime lake pollutant?
a) Iodine
b) Phosphorous
c) Potassium
d) Sodium

View Answer

Answer: b
Explanation: Phosphorous is a prime lake pollutant that promotes the algal bloom and destroys the quality and appearance of a lake.




2 - Question

The turbulence decreases the DO content of water.
a) True
b) False

View Answer

Answer: b
Explanation: The turbulence increases the DO content of water, however, beyond a certain limit, it scours the sediments placed at the bottom.




3 - Question

The dilution factor is expressed by _____________
a) Volume of diluted sample + Volume of sewage
b) Volume of diluted sample / Volume of sewage
c) Volume of diluted sample – Volume of sewage
d) Volume of diluted sample* Volume of sewage

View Answer

Answer: b
Explanation: The dilution factor is the ratio of volume of diluted sample of water to the volume of sewage. It is used in finding the BOD of water.




4 - Question

The tolerance limit of BOD of sewage to be disposed on land is ____________
a) 100ppm
b) 200ppm
c) 500ppm
d) 400ppm

View Answer

Answer: c
Explanation: The tolerance limit of BOD of sewage to be discharged into sea water is 100ppm while to be disposed on land is 500ppm.




5 - Question

The tolerance limit of pH value of sewage to be discharged into sea water is ____________
a) 1-5ppm
b) 2-9ppm
c) 5.5-9ppm
d) 6-10ppm

View Answer

Answer: c
Explanation: The tolerance limit of pH value of sewage to be discharged into sea water or to be disposed on land is between 5.5 and 9ppm.




6 - Question

The dilution factor is 400. What should be the type of treatment given to the water?
a) Preliminary treatment
b) Sedimentation, Flocculation
c) Complete treatment
d) No treatment

View Answer

Answer: a
Explanation: When the dilution factor lies between 300 and 500, then preliminary treatment is given to the water.




7 - Question

The tolerance limit of oil and grease of sewage to be disposed on land is ____________
a) 40ppm
b) 30ppm
c) 20ppm
d) 10ppm

View Answer

Answer:b
Explanation: The tolerance limit of oil and grease of sewage to be disposed on land is 30ppm while on sea water is 20ppm.




8 - Question

The minimum depth to which sewage should be discharged of sea water is ____________
a) 0.5m
b) 1m
c) 2m
d) 3m

View Answer

Answer: d
Explanation: The minimum depth to which sewage should be discharged of sea water is 3m to avoid marine pollution.




9 - Question

The tolerance limit of COD of sewage to be discharged in sea water is ____________
a) 250ppm
b) 100ppm
c) 40ppm
d) 20ppm

View Answer

Answer: a
Explanation: The tolerance limit of COD of sewage to be discharged in sea water and on land for irrigation purpose is 250ppm.

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