Question

A sewage treatment plant involves the following steps in its working: Aeration tank, Grit and sand removal tank, Secondary sedimentation tank, Bar screen, primary sedimentation tank
a)Arrange all the above steps in the correct order in which they occur in the sewage treatment plant.
b)Which step gives most of the sludge which is used for obtaining biogas fuel?

Answer 1

Answer:

(a) Sludge is scraped out and skimmer removes floating grease.

(b) Water is made to settle in a large tank with a slope in the middle.

(c) Large objects like plastic bags are removed by passing wastewater through bar screens.

(d) Sand, grit and pebbles are made to settle by decreasing the speed of incoming wastewater.

(e) Wastewater enters a grit and sand removal tank.

Q2.)

Secondary treatment stage of polluted water in sewage treatment plant gives most of the sludge.

Answer 2

Answer:

Explanation:

• Bar screen

• Grit and sand removal tank.
• First sedimentation tank.

• Aeration tank.

First sedimentation tank gives most of the sludge which is used for obtaining biogas fuel.