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Microbes in Human Welfare — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYMicrobes in Human Welfare3 Marks
Question
This sludge can be used as an inoculum or as a source of biogas. Explain.
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Answer

  • A small amount of activated sludge is pumped back into the aeration tank as inoculum; the microbes grow into flocs and consume the organic matter to reduce the BOD.
  • A large part of the activated sludge is pumped into anaerobic sludge digesters where the anaerobic bacteria digest the bacteria and fungi of the flocs; during this process gases like methane, hydrogen sulphide and carbon dioxide are formed, which constitute the biogas.

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