Environmental Engineering Multiple Choice Questions on “Devices Associated with Sewer”.
1. Which of the following is not a sewer appurtenance?
a) Storm regulator
b) Flushing tank
c) Water tank
d) Manholes
Answer: c
Clarification: Sewer appurtenance are the structures that are constructed for the efficient performance and maintenance of sewers. The water tank is not a sewer appurtenance.
2. ______ provides the working space for maintenance and inspection of sewers.
a) Lamp holes
b) Manholes
c) Flushing tanks
d) Working chamber
Answer: d
Clarification: Working chamber provides the working space for maintenance and inspection of sewers. It is situated at the lower part of the manhole.
3. The minimum thickness of the side wall of the manhole is __________
a) 50mm
b) 100mm
c) 225mm
d) 300mm
Answer: c
Clarification: The minimum thickness of the side wall of the manhole is 225mm and they are commonly made of bricks.
4. Which of the following is situated above the working chamber in a deep manhole?
a) Main sewer
b) Access shaft
c) Branch sewer
d) Channel
Answer: b
Clarification: The access shaft lies above the working chamber which is just below the manhole cover.
5. If the depth of excavation is 4m. What is the thickness of the brick wall of manhole?
a) 12cm
b) 16cm
c) 20cm
d) 26cm
Answer: d
Clarification: The thickness of brick wall of manhole (in cm) = 10 + 4*depth of excavation (in m) = 10 + 4*4 = 26cm.
6. Into how many types manholes are classified on the basis of depth of manhole?
a) 3
b) 5
c) 6
d) 7
Answer: a
Clarification: Manholes are classified into Shallow, Normal and Deep on the basis of depth of the manhole.
7. The minimum diameter of the access shaft for a circular manhole is __________
a) 60cm
b) 20cm
c) 30cm
d) 10cm
Answer: a
Clarification: Access shaft is the upper portion of manhole whose minimum diameter for a circular manhole is 60cm.
8. The manhole in which inclined pipe for transfer of sewage from branch to main sewer is __________
a) Deep manhole
b) Ramp
c) Drop manhole
d) Normal manhole
Answer: b
Clarification: Ramp has an inclined pipe for the transfer of sewage which is used when the drop is less.
9. The thickness of the manhole frame is __________
a) 10cm
b) 15cm
c) 20cm
d) 40cm
Answer: c
Clarification: The manhole frame is made of cast iron having 10cm width and the thickness is 20cm.
10. The minimum diameter of the working chamber for a circular manhole is __________
a) 0.8m
b) 0.9m
c) 1m
d) 1.2m
Answer: d
Clarification: The working chamber is the lower portion of the manhole having a minimum diameter of 1.2 m.
11. The manhole in which vertical pipe is used for the transfer of sewage from branch to main sewer is __________
a) Deep manhole
b) Ramp
c) Drop manhole
d) Normal manhole
Answer: c
Clarification: Drop manholes are provided with vertical pipe so that the sewage does not fall on the people working at manhole.
12. Which sewer appurtenance allows lamp in the sewer?
a) Catch basin
b) Drop manhole
c) Lamp hole
d) Storm regulators