Test: Types Of Settling Tanks

QUESTION: 1

How many types of sedimentation tanks are there on the basis of method of operation?

A.
2
B.
3
C.
4
D.
5

Solution:

Explanation: There are two types sedimentation tanks on the basis of method of operation, namely Fill and draw type and Continuous flow type.

QUESTION: 2

In which type of sedimentation, the flocculent suspension of the intermediate concentration takes place?

A.
Type I sedimentation
B.
Type II sedimentation
C.
Type III sedimentation
D.
Type IV sedimentation

Solution:

Explanation: In type III sedimentation, the inter-particle forces hold the particle together and the flocculent suspension of the intermediate concentration takes place.

QUESTION: 3

In which type of sedimentation,the flocculent suspension of high concentration takes place?

A.
Type I sedimentation
B.
Type II sedimentation
C.
Type III sedimentation
D.
Type IV sedimentation

Solution:

Explanation: In type IV sedimentation,the flocculent suspension of high concentration takes place and particles comes in contact with each other resulting in the formation of structure.

QUESTION: 4

When the impurities are separated by the gravitation of settling particles, the operation is called ______

A.
Sedimentation with coagulant
B.
Plain sedimentation
C.
Secondary sedimentation
D.
Disinfection

Solution:

Explanation: In plain sedimentation, the impurities are separated from a suspending fluid by use of natural forces like gravitational forces.

QUESTION: 5

What is the settling velocity of the particle in the wastewater if its diameter is 2 * 10^-3cm. Given G=2.65, viscosity v=8 * 10^-3cm²/Sec?

A.
0.01cm/Sec
B.
0.13cm/Sec
C.
0.24cm/Sec
D.
0.36cm/Sec

Solution:

Explanation: Settling velocity of the particle in wastewater is given by vs=g (G-1) d²/18v
Specific gravity G=1, g=981cm²/Sec, viscosity v=8 * 10^-3cm²/Sec
vs = 981 * (2.65-1) * 0.002 * 0.002/(18 * 0.008) = 0.13cm/Sec.