Question

Solid settled in wwtp during primary and secondary stage

Answer 1

In any waste water treatment plants, two processes are followed, they are primary treatment and secondary treatment of waste water.

Explanation:

• Primary treatment of waste water generally removes solid particles that floats or can settle down.
• The floating solid wastes includes small pieces of plastics, wood, etc.
• Other solid waste like sand, silt and gravel settle at the bottom due to gravity and which is then removed.
• After this the waste water is taken for the secondary treatment which removes the dissolved organic matters which cannot be removed using mechanical process.
• It is generally treated with the help of microbes which eats the organic matter and form flocs.
• Flocs are the solid mass of microbial aggregates which are removed from the water after the biological treatment is completed during the secondary treatment.