Question

What would happen if oxygen availability to activated sludge flocs is reduced?

• A. The rate of organic matter degradation will increase
• B. The centre of flocs will become anoxic which would cause death of microbes and eventually breakage of flocs
• C. Flocs will increase in size as anaerobic bacteria would grow around flocs
• D. Protozoa would grow in large numbers

Answer 1

The correct option is B The centre of flocs will become anoxic which would cause death of microbes and eventually breakage of flocs

The activated sludge process is a type of wastewater treatment process for treating sewage using aeration and a biological floc composed of bacteria and protozoa.
Aeration keeps the microbes in suspension, which allows microbial growth. The microbes growing in the wastewater feed on the organic matter to form flocs which can be settled out later in the process.
If oxygen availability to activated sludge flocs (masses of bacteria associated with fungal filaments to form mesh like structure) is reduced, the centre of flocs will becomes anoxic which would cause death of bacteria and eventually breakage of flocs.