Water Supply & Treatment MCQ for GATE Civil Engineering
247 Questions5 Difficulty Levels10-12% in GATEFree Practice
Environmental Engineering covers water supply, wastewater treatment, air pollution, and solid waste management — carrying 8-12 marks in GATE CE. Water treatment processes and wastewater treatment (especially activated sludge process) are the most frequently tested topics. The Streeter-Phelps oxygen sag curve is a GATE classic.
Difficulty Levels
L1 · Foundation · 124 Qs
L2 · Understanding · 32 Qs
L3 · Application · 63 Qs
L4 · Analysis · 25 Qs
L5 · GATE Ready · 1 Qs
Key Topics Covered
Water quality parameters (BOD, COD, DO)
Sedimentation & coagulation
Filtration (slow sand, rapid sand)
Chlorination & disinfection
Activated sludge process
Trickling filters
Sludge treatment
Streeter-Phelps equation
Key Formulas
BODt = L₀(1−e^(−kt))
DO sag: dD/dt = KdL − KrD (Streeter-Phelps)
Detention time = Volume/Flow
SVI = (SV₃₀ × 1000)/MLSS
F/M = Q·S₀/(V·X)
GATE Exam Tip: BOD kinetics (first-order reaction) and the Streeter-Phelps DO sag curve are must-know. For activated sludge, practice F/M ratio, SVI, and return sludge ratio calculations. Sedimentation tank design (detention time, overflow rate) is straightforward scoring.
Practice Questions — Try 16 Samples
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Q1 · Level 1 · EE-WTR-1023
What is the primary outcome of disinfecting potable water?
Q2 · Level 1 · EE-WTR-1085
When designing a sewerage system, engineers must account for which of the following flow conditions?
Q3 · Level 1 · EE-WTR-1197
Which empirical formula is commonly employed to estimate the water required for firefighting in a municipality?
Q4 · Level 2 · EE-WTR-1090
In the context of sedimentation tanks used in environmental engineering, the rate at which a particle settles is influenced by which factors?
Q5 · Level 2 · EE-WTR-1138
For conveying wastewater beneath culverts, the most commonly employed sewer configuration is:
Q6 · Level 2 · EE-WTR-1035
What design lifespan is typically considered for sewerage systems in environmental engineering?
Q7 · Level 3 · EE-WTR-1116
The per capita water demand for a municipality is influenced by which of the following factors?
Q8 · Level 3 · EE-WTR-1149
In the design of wastewater conduits, which of the following factors does NOT influence the velocity of flow?
Q9 · Level 3 · EE-WTR-1128
For a particle to settle faster in a sedimentation basin, which of the following conditions is most favorable?
Q10 · Level 3 · EE-WTR-1065
If the time of concentration for a catchment area is 9 minutes, what is the predicted rainfall intensity in mm/hr based on the British Ministry of Health formula?
Q11 · Level 3 · EE-WTR-1218
Which established formula, not relying on empirical correlations, is predominantly employed to ascertain the speed of groundwater movement?
Q12 · Level 4 · EE-WTR-1168
The typical residence time allocated in coagulation tanks for water treatment is in the range of:
Q13 · Level 4 · EE-WTR-1221
For a wastewater treatment context, the specific yield or capacity of a well is typically quantified in units of:
Q14 · Level 4 · EE-WTR-1073
Which method is predominantly employed for disinfecting water in swimming pools?
Q15 · Level 4 · EE-WTR-1105
Among the substances listed, which is commonly employed in water treatment processes for the specific purpose of controlling algal growth?
Q16 · Level 5 · EE-WTR-0010
A water treatment plant treats 50 MLD. Design the sedimentation stage: the target SOR is 25 m³/m²/day and detention time is 3 hours. Calculate (a) the required surface area, (b) the tank volume, and (c) the effective depth of the tank.