Question

Question 7.

What is sludge? Explain how it is treated?

Answer 1

Sludge is human waste (like faeces) in wastewater left during sewage treatment. Since it is organic waste, it is used to produce biogas and manure. Sludge is collected by a scrapper.

It is transferred to a separate tank where it is decomposed by the anaerobic bacteria. The biogas produced in the process can be used as fuel. After the aerator tank, microbes and human waste settle down and form activated sludge. The activated sludge is about 97% water. The water is removed by sand drying beds or machines.