Question

Discuss the stages of waste water treatment process.

Answer 1

The stages of waste water treatment process are as follows:
(a) Primary treatment: This stage is a mechanical process involving screening and settling of large particles from waste water using vertical bars and grit chambers. After screening, water is passed into sedimentation tanks.

(b) Secondary treatment: This stage is a biological process that involves the breakdown of the organic matter obtained from the primary treatment, with the help of bacteria, producing biogas. Water is sent into aeration tanks and air is blown through them to speed up the treatment of water.

(c) Tertiary treatment: This stage is a chemical process and the last stage in the treatment of water. Chemicals are added to remove phosphorous and nitrogen from water. Bacteria and other germs are killed by the addition of chlorine.