Question

What is the key difference between primary and secondary sewage treatment?

Answer 1

Sewage treatment is the process of removing contaminants from municipal wastewater, containing mainly household sewage plus some industrial wastewater. Physical, chemical, and biological processes are used to remove contaminants and produce treated wastewater that is safe enough for release to the environment .

Answer 2

$\sf\underline{ Primary \: \: sewage \: \: treatment }$ :-

⟶ Physical removal of large and small particles through filtration and sedimentation is called primary sewage treatment.

⟶ It is an easy process and less expensive.

$\sf\underline{ Secondary \: \: sewage \: \: treatment }$ :-

⟶ It is a biological treatment.

⟶ The primary effluent is passed into large section tanks.

⟶ It is a time consuming, expensive and complicated process.