Engineering Questions with Answers - Multiple Choice Questions

Environmental Engineering MCQ – Material for Sewers

1 - Question

The diameter of plain cement concrete pipes used for sewerage system is __________
a) 20mm
b) 30mm
c) 90mm
d) 63mm

View Answer

Answer: c
Explanation: The range of diameter of plain cement concrete pipes for sewerage system is from 80mm to 450mm and its thickness varies from 25 to 35mm




2 - Question

The grade of concrete used in plain cement concrete sewer is __________
a) M5
b) M10
c) M15
d) M20

View Answer

Answer: d
Explanation: M20 grade of concrete is used in plain cement concrete sewer. It includes cement, fine aggregate and coarse aggregate in the ratio of 1:1.5:3.




3 - Question

Which of the following is incorrect regarding Cement concrete sewers?
a) They are economical
b) Can be manufactured at the site
c) They can be made of any desired strength
d) They cannot withstand tensile stress

View Answer

Answer: d
Explanation: Cement concrete sewer can withstand internal and external pressure and are strong enough to resist both tensile and compressive stress.




4 - Question

The crown corrosion takes place due to formation of __________
a) CO2
b) H2O
c) H2S
d) HCl

View Answer

Answer: c
Explanation: The crown corrosion takes place due to the formation of H2S which takes place because of aerobic and anaerobic condition in lower layers of sewage.




5 - Question

The cement concrete sewers are lined with vitrified clay lining to prevent __________
a) Dampness of sewer
b) Algae growth in the sewer
c) Crown corrosion
d) Foul smell of sewer

View Answer

Answer: c
Explanation: The interiors of the sewers are lined with vitrified clay to prevent corrosion and erosion of sewer.




6 - Question

Which of the following method is not used for treating crown corrosion?
a) Full runs of sewer
b) Increasing the sulfate content of sewage
c) Aeration and chlorination of sewage
d) Vitrified clay lining of sewer

View Answer

Answer: b
Explanation: The pretreatment of sewage is done for treating the crown corrosion to reduce the sulfate content from sewage.




7 - Question

Which of the following is incorrect regarding Stoneware sewer?
a) They can withstand tensile stress
b) They are highly resistant to sulfide corrosion
c) They have smooth interior
d) They are high compressive strength

View Answer

Answer: a
Explanation: Stoneware sewer can not be used where sewage flow under pressure as they are weak in tension.




8 - Question

The range of diameter of cast iron sewer is __________
a) 20-100mm
b) 150-750mm
c) 40-250mm
d) 100-250mm

View Answer

Answer: b
Explanation: The diameter of cast iron sewer lies between 150mm and 750mm and its length lies between 3 m to 3.5m.




9 - Question

Identify the correct statement from the following regarding Cast iron sewer.
a) They have low internal pressure
b) They are not leakage proof
c) They cannot withstand heavy external loads
d) They are preferred in water supply lines

View Answer

Answer: d
Explanation: Cast iron is 100% leakage proof, so they are preferred in water supply lines.

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