Which letter in the diagram corresponds to the point at which sludge is dried before being disposed of?

Primary And Secondary

Refers to the first and second stages or levels in processes, industries, or education, often indicating a primary source or activity and its subsequent development or refinement.

Sewage Treatment

Sewage treatment involves the process of removing contaminants from wastewater, primarily from household sewage, to produce an effluent that is safe enough to release into the environment or to be reused.