Q50 / 226 · NTA Abhyas (NEET) 2020 · Zoology · Microbes in Human Welfare

Once BOD from the sewage is reduced significantly, the 'flocs' are allowed to sediment and it is known as _________.

  • A
    primary sludge
  • B
    secondary sludge
  • Correct answer
    C
    activated sludge
  • D
    inactivated sludge

Solution

Once BOD of sewage water is reduced significantly, the effluent is then passed into the settling tank where the bacterial ' flocs' are allowed to sediment. This sediment is called as activated sludge.

Hence, the correct answer is option: 'C'.

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