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-1062
What is the typical approximate percentage of available chlorine in fresh bleaching powder used for wastewater treatment?
Q2 · Level 1 · EE-WTR-0004
The purpose of adding alum (aluminium sulphate) in water treatment is:
Q3 · Level 1 · EE-WTR-1219
The process of aeration applied to water serves to eliminate which undesirable characteristic?
Q4 · Level 2 · EE-WTR-1078
The Hardy Cross method for analyzing distribution networks is characterized by:
Q5 · Level 2 · EE-WTR-1118
Within the context of wastewater treatment, which of the following units operates under strictly anaerobic conditions?
Q6 · Level 2 · EE-WTR-1153
In water purification processes, which chemical compound is commonly employed for the eradication of algae?
Q7 · Level 3 · EE-WTR-1012
The determination of residual chlorine in water samples is commonly performed using which analytical method?
Q8 · Level 3 · EE-WTR-1024
When the total hardness of water exceeds its total alkalinity, what is the value of carbonate hardness?
Q9 · Level 3 · EE-WTR-1117
Alkalinity in water samples is quantified in milligrams per liter, expressed as an equivalent concentration of which substance?
Q10 · Level 3 · EE-WTR-1089
For a fixed rate of water flow, how can the effectiveness of a sedimentation tank in removing suspended solids be improved?
Q11 · Level 3 · EE-WTR-1155
In the field of environmental engineering, structures designed to collect water from its sources are referred to as:
Q12 · Level 4 · EE-WTR-1017
The chemical characteristics of fresh sewage and septic sewage are typically described as:
Q13 · Level 4 · EE-WTR-1061
For the backwashing of rapid sand filters, the approximate percentage of filtered water utilized is:
Q14 · Level 4 · EE-WTR-1119
For analyzing water distribution networks, particularly those with long and narrow pipe layouts, which method offers the most appropriate approach?
Q15 · Level 4 · EE-WTR-1113
Aluminum sulfate (Alum) functions optimally as a coagulant within which pH range for water treatment?
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.