Sedimentation Tanks MCQs : This section focuses on the "Sedimentation Tanks" in Waste Water Engineering. These Multiple Choice Questions (MCQs) should be practiced to improve the Waste Water Engineering skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
Sedimentation tank, also called?
A. settling tank
B. clarifier
C. Both A and B
D. None of the above
View Answer
Ans : C
Explanation: Sedimentation tank, also called settling tank or clarifier, component of a modern system of water supply or wastewater treatment.
Question 2
A sedimentation tank allows suspended particles to settle out of water or wastewater as it flows slowly through the tank, thereby providing some degree of purification.
A. TRUE
B. FALSE
C. Can be true or false
D. Can not say
View Answer
Ans : A
Explanation: True, A sedimentation tank allows suspended particles to settle out of water or wastewater as it flows slowly through the tank, thereby providing some degree of purification.
Question 3
A layer of accumulated solids, called?
A. coagulants
B. sewage
C. settle
D. sludge
View Answer
Ans : D
Explanation: A layer of accumulated solids, called sludge, forms at the bottom of the tank and is periodically removed.
Question 4
Which of the following added to the water prior to sedimentation in order to facilitate the settling process?
A. trickling
B. coagulants
C. grit
D. None of the above
View Answer
Ans : B
Explanation: In drinking-water treatment, coagulants are added to the water prior to sedimentation in order to facilitate the settling process, which is followed by filtration and other treatment steps.
Question 5
In modern sewage treatment, primary sedimentation must be followed by secondary treatment to increase purification efficiencies.
A. Yes
B. No
C. Can be yes or no
D. Can not say
View Answer
Ans : A
Explanation: Yes, In modern sewage treatment, primary sedimentation must be followed by secondary treatment (e.g., trickling filter or activated sludge) to increase purification efficiencies
Question 6
What are the ponds constructed for removing entrained solids called?
A. Clarifiers
B. Settling basins
C. Eco-ponds
D. Ditches
View Answer
Ans : B
Explanation: Settling basins are ponds constructed for the purpose of removing entrained solids by sedimentation. Clarifiers are tanks built with mechanical means for continuous removal of solids being deposited by sedimentation.
Question 7
What is the accumulated layer at the bottom of the tank called as?
A. Flocs
B. Sediment
C. Sludge
D. Sewage
View Answer
Ans : C
Explanation: A layer of accumulated solids called sludge forms at the bottom of the tank and is periodically removed. Prior to sedimentation, coagulants are added to the water in order to facilitate the settling process, which is followed by filtration and other treatment steps.
Question 8
Which is the primary force acting on the Settleable particles?
A. Gravitational force
B. Centrifugal force
C. Mechanical force
D. Radial force
View Answer
Ans : A
Explanation: The applied force such as gravity and a drag force that is due to the motion of the particle through the fluid. The applied force is not affected by the particle’s velocity. The drag force is a function of the particle velocity.
Question 9
How many types of settling are present?
A. 1
B. 2
C. 3
D. 4
View Answer
Ans : D
Explanation: There are four types of settling present. Type 1 is for non-flocculent particles, type 2 is for flocculent particles, type 3 is called as a zone or hindered settling, type 4 is called as compression settling.
Question 10
Sedimentation is usually preceded by treatment using ______________ to remove large objects and coarse solids.
A. bar screens
B. grit chambers
C. bar screens and grit chambers
D. None of the above
View Answer
Ans : C
Explanation: Sedimentation is usually preceded by treatment using bar screens and grit chambers to remove large objects and coarse solids.