What is sludge? Explain how it is treated

cbse
cbse-class-7-science
waste-water-story

#1

What is sludge? Explain how it is treated.
Answer:
Semi-solids such as faeces that settle down during wastewater treatment are called sludge. This sludge is removed using a scraper and then transferred to a tank where it is decomposed by anaerobic bacteria to produce biogas. This biogas is used as a low- cost fuel for heating, cooking, etc. It is also used to produce electricity.