GATE Water and Waste Water Quality and Treatment: Primary, secondary and tertiary treatment, effluent standards – Previous Year Questions

7 GATE previous year questions on Primary, secondary and tertiary treatment, effluent standards (Water and Waste Water Quality and Treatment, Civil Engineering) with answers and explanations, from every paper.

1. GATE 2023 CE (CE1) Q64 (2 marks, Numerical answer) – The wastewater inflow to an activated sludge plant is 0.5 m3/s, and the plant is to be operated with a food to microorganism ratio of 0.2 mg/mg-d. The…
2. GATE 2024 CE (CE2) Q60 (2 marks, Numerical answer) – A circular settling tank is to be designed for primary treatment of sewage at a flow rate of 10 million liters/day. Assume a detention period of 2.0…
3. GATE 2025 CE (CE2) Q62 (2 marks, Numerical answer) – A community generates 1 million litres/day (MLD) of wastewater. This wastewater is treated using activated sludge process (ASP). The working volume of…
4. GATE 2025 CE (CE1) Q45 (2 marks, Multiple select) – A facultative pond system is employed for wastewater treatment. Which of the following statements is/are true:
5. GATE 2026 CE (CE2) Q29 (1 mark, Multiple choice) – The grown algae are useful in the operation of
6. GATE 2026 CE (CE2) Q64 (2 marks, Numerical answer) – Anaerobic bacteria are being utilized for the destruction of biodegradable organic content of wastewater measured in terms of Chemical Oxygen Demand…
7. GATE 2026 CE (CE1) Q25 (1 mark, Multiple select) – Which of the following components is/are NOT removed in the secondary treatment of sewage?