Sewage treatment an purification why it it important for general public health?

the sewage treatment plant is physically, biologically and chemically clean & safe to discharge back to environment

To prevent the pollution of ground water, surface water, marine environment, Flora & Fauna, General environment.

To reduce the spread of communicable diseases caused by the pathogenic organisms in the sewage such as cholera, typhoid, diarrhea, intestinal worms etc.