Question

The function of the sedimentation tank in sewage treatment is to:
A. Disinfect the sewage
B. Aerate the sewage
C. Remove water content
D. Remove suspended solids

Answer 1

A sedimentation tank allows suspended particles to settle out of water or water waste as it flows slowly through the tank, thereby providing some degree of purification.

Complete step by step answer:
Sedimentation tank, also called settling tank. It is also known as clarifier.in sedimentation tank, a layer of accumulated solids, known as sludge, forms at the bottom of the tank and is periodically removed. Hence we can say it is used to remove the suspended solids.

So, the correct answer is Option D ”.

Additional Information:
Sedimentation is defined as a physical water treatment process to remove suspended solids. It uses gravity. Removal of the suspended particles by sedimentation depends upon the size, Zeta potential and specific gravity of those particles. Various factor on which classification of sedimentation tank depends are:
1. Based on method of operation
2. Based on shape
3. Based on location

Note:
The step involved in sewage treatment are:
The waste is screened and pumped to the point of removal.
Then the process of Grit removal is done
In the Primary settling step, the heavier organic solids or sludge is allowed to settle to the bottom.
The waste is then treated using the process of aeration.
In Secondary settling step, effort is done achieve a degree of effluent quality by removing settleable solids and a using biological process to remove dissolved and suspended organic compounds
In this step the water received from the above step is again Filtered to remove large objects. Fat and grease is also removed.
Disinfection of the water received is done to kill or inactivate microorganisms
In the next step, an Oxygen uptake test is done to ensure the quality of the sewage treatment system.
The remaining sludge is then treated to manage and dispose of sewage.