The correct answer is D. Remove suspended solids.
A sedimentation tank is a type of tank used in sewage treatment to remove suspended solids from the sewage. The tank is typically rectangular in shape and has a sloping bottom. The sewage enters the tank at the top and flows slowly down the slope. As the sewage flows, the suspended solids settle to the bottom of the tank. The clear water then flows out of the tank at the top.
The sedimentation tank is an important part of the sewage treatment process. It helps to remove solids that can cause problems in the later stages of treatment. The solids that are removed from the sedimentation tank can be disposed of in a landfill or incinerated.
Option A is incorrect because the sedimentation tank does
not disinfect the sewage. Disinfection is done in a separate step in the sewage treatment process.Option B is incorrect because the sedimentation tank does not remove water content. The water content of the sewage is reduced in a later step in the sewage treatment process.
Option C is
incorrect because the sedimentation tank does not aerate the sewage. Aeration is done in a separate step in the sewage treatment process.