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GATE 2016 CE (CE1) – Question 30

Water and Waste Water Quality and Treatment · Primary, secondary and tertiary treatment, effluent standards · 1 mark · Multiple choice

Match the items in Group – I with those in Group – II and choose the right combination. Group - I P. Activated sludge process Q. Rising of sludge R. Conventional nitrification S. Biological nitrogen removal Group - II 1. Nitrifiers and denitrifiers 2. Autotrophic bacteria 3. Heterotrophic bacteria 4. Denitrifiers

  1. P-3, Q-4, R-2, S-1
  2. P-2, Q-3, R-4, S-1
  3. P-3, Q-2, R-4, S-1
  4. P-1, Q-4, R-2, S-3

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Show answer and explanation

Correct answer: (A) P-3, Q-4, R-2, S-1

Explanation

Activated-sludge carbon removal relies on heterotrophs(P3). Denitrification produces gas that can cause rising sludge(Q4). Nitrification is carried out by autotrophs(R2), while combined nitrogen removal uses both nitrification and heterotrophic denitrification(S1). The complete matching is **A**.