Treatment of sewage depends on a strategy given ordinarily. At the point when a consistent steady stock of air is pumped into a tank containing sewage which has been screened to eliminate all drifting flotsam and jetsam and non solvent items in sewage, microorganisms which are available in it get enacted. These microorganisms are available in the slime which makes up a significant piece of sewage, and they consume the poisons in the sewage while the air supply rejuvenates them and keeps them alive and multiplying.