Environmental Engineering Questions for Experienced people on “Egg Shaped Sewers and Other Sewer Sections”.
1. Which of the following sewer is called as an ovoid sewer?
a) Asbestos cement sewer
b) Egg shaped sewer
c) Plain cement sewer
d) Salt glazed sewer
Answer: b
Clarification: Egg shaped sewer is an oval shaped sewer and is also called as an ovoid sewer.
2. Egg shaped sewers are more suitable in a combined system during dry weather flow.
a) True
b) False
Answer: b
Clarification: Egg shaped sewers are more suitable in a combined system during maximum rain water flow as for low flows, they give sufficient velocity.
3. Which of the following is incorrect regarding Egg shaped sewer?
a) It is cheap
b) It is difficult to construct
c) It is less stable
d) It is mainly circular in shape
Answer: a
Clarification: The Egg shaped sewer is expensive as more material is required than other sewer. Moreover, the cost of construction is high.
4. The upper portion of Egg shaped sewer is called as _____
a) Level
b) Arch
c) Invert
d) Wedge
Answer: b
Clarification: The upper portion of Egg shaped sewer is called as arch which is circular in shape and is larger than the lower circular section.
5. The Egg shaped sewer provides ____ velocity for low flows over the circular sewer of equal capacity.
a) Lesser
b) Higher
c) Slightly higher
d) Very high
Answer: c
Clarification: The Egg shaped sewer provides slightly higher velocity for low flows over the circular sewer of equal capacity. This makes it useful during a combined sewerage system.
6. The lower portion of Egg shaped sewer is known as _____
a) Roof
b) Invert
c) Arch
d) Wedge
Answer: b
Clarification: The lower portion of Egg shaped sewer is known as invert which is circular in shape and is smaller than the arch.
7. The height of standard section of Egg shaped sewer is ______ the new shaped section.
a) Equal to
b) Twice of
c) Less than
d) Half of
Answer: a
Clarification: The height of both the standard and a new shaped section of Egg shaped sewer is 3 times the radius of sewer. So, their heights are equal.
8. The ratio of the width of the standard section and new shaped section of Egg shaped section is __________
a) 1:2
b) 2:1
c) 1:1
d) 1:3
Answer: c
Clarification: Width of standard section = 2 times radius of sewer
Width of new shaped section = 2 times radius of sewer
So, their ratio = 1:1.
9. The radius of invert of the standard section of Egg shaped sewer is ____ of the new shaped section.
a) Twice
b) Thrice
c) Half
d) Equivalent
Answer: a
Clarification: Let k be the radius of sewer. The radius of invert of the standard section= 0.5k and the radius of invert of the new shaped section = 0.25k. So, radius of invert of the standard section is twice the new shaped section of Ovoid sewer.
10. _______ denotes the characteristic size of circular cross section of sewer.
a) DN
b) MN
c) QW
d) SE
Answer: a
Clarification: DN denotes the internal diameter of circular cross section of sewer. It is measured in mm.
11. The arch cross section is divided into how many types?
a) 2
b) 3
c) 4
d) 5
Answer: b
Clarification: The arch cross section is divided into 3 types, namely Normal, Extended and Squashed arch cross section.
12. One side walkway is a type of __________
a) Circular cross section
b) Channel cross section
c) Ovoid cross section
d) Arch cross section
Answer: b
Clarification: The channel cross section is divided into 2 types. It includes One side walkway and Two side walkway channel cross section.
13. Which of the following ovoid cross section has the maximum nominal size range?
a) Squashed
b) Extended
c) Normal
d) Wide
Answer: a
Clarification: Squashed ovoid cross section has the maximum nominal size range with breadth and height as 3200mm.
14. There is less deposition of waste in ovoid cross-section.
a) True
b) False
Answer: a
Clarification: Ovoid sewer cross-section offers less deposition of waste which results in better handling of waste in sewage treatment plant during dry weather and reduced emission of waste during wet weather.
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