GATE CE 2026 Set 1 — Question 25

MSQ+1 / -0MediumSecondary TreatmentWastewater Treatment ProcessesEnvironmental Engineering

Environmental Engineering → Wastewater Treatment Processes → Secondary Treatment

Last updated 5 September 2026

Question

Which of the following components is/are NOT removed in the secondary treatment of sewage?

Correct answer (A) Suspended settleable organic solids; (C) Pathogens; (D) Fat and grease Solution Secondary treatment (biological treatment) primarily targets the removal of dissolved and colloidal organic matter (B) through microbial action. Suspended settleable organic solids (A) are primarily removed during primary treatment in the Primary Sedimentation Tank (PST). Fat and grease (D) are removed during pre-treatment in skimming tanks. Pathogens (C) are primarily targeted during tertiary treatment (disinfection), although some incidental removal occurs in secondary stages. Therefore, (A), (C), and (D) are NOT the primary components removed in secondary treatment. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (A) Suspended settleable organic solids; (C) Pathogens; (D) Fat and grease Solution Secondary treatment (biological treatment) primarily targets the removal of dissolved and colloidal organic matter (B) through microbial action. Suspended settleable organic solids (A) are primarily removed during primary treatment in the Primary Sedimentation Tank (PST). Fat and grease (D) are removed during pre-treatment in skimming tanks. Pathogens (C) are primarily targeted during tertiary treatment (disinfection), although some incidental removal occurs in secondary stages. Therefore, (A), (C), and (D) are NOT the primary components removed in secondary treatment.

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