Explore topic-wise MCQs in Environmental Engineering.

This section includes 180 Mcqs, each offering curated multiple-choice questions to sharpen your Environmental Engineering knowledge and support exam preparation. Choose a topic below to get started.

101.

Which of the following is correctly paired in the following figure?

A. C – Impeller
B. D – Outlet
C. F – Deflecting wall
D. E – Impeller
Answer» E.
102.

What will be the surface area of the basin for a flow of 2*10⁶ litre per day having a surface loading rate 10,000 litre/day/m²?

A. 100
B. 200
C. 300
D. 400
Answer» C. 300
103.

The design value of surface loading for horizontal flow circular sedimentation is _______

A. 30-40m³/m²/d
B. 20-30m³/m²/d
C. 10-20m³/m²/d
D. 50-100m³/m²/d
Answer» B. 20-30m³/m²/d
104.

Settling tank efficiency is reduced by _______i. Eddy currentii. Surface currentiii. Density current

A. i, ii
B. i, ii, iii
C. ii, iii
D. i, iii
Answer» C. ii, iii
105.

1cm per second settling velocity corresponds to a surface loading of ______ litre per day per m².

A. 36000
B. 864000
C. 24000
D. 6000
Answer» C. 24000
106.

The thickness of Anthracite used in dual media filter is __________

A. 10-20cm
B. 20-30cm
C. 30-40cm
D. 40-50cm
Answer» D. 40-50cm
107.

The chemical composition of Alum is _____________

A. Al₂ (SO₄)₃.18H₂O
B. Al₂ (SO₄)₂.18H₂O
C. Al₃ (SO₄)₂.18H₂O
D. Al₄ (SO₄)₃.18H₂O
Answer» B. Al₂ (SO₄)₂.18H₂O
108.

The chemical compound which is insoluble in water, formed when alum is added to water is _____________

A. Al (OH)₃
B. CaSO₄
C. CO₂
D. Ca (OH)₃
Answer» B. CaSO₄
109.

What is formed when coagulant is added to water?

A. Scum
B. Soap
C. Bubbles
D. Floc
Answer» E.
110.

Settling velocity of a spherical body in a viscous fluid is given by ___________

A. Reynolds law
B. Newton’s law
C. Stokes law
D. Charles law
Answer» D. Charles law
111.

The time period for which the water is stored in a sedimentation tank is called _____

A. Time of flow
B. Frequency of flow
C. Settling time
D. Detention period
Answer» E.
112.

What is the settling velocity of the particle if its diameter is 2 * 10⁻³cm. Given G=2.65, viscosity v=8 * 10⁻³cm²/Sec?

A. 0.01cm/Sec
B. 0.13cm/Sec
C. 0.24cm/Sec
D. 0.36cm/Sec
Answer» C. 0.24cm/Sec
113.

The settling velocity of spherical particle is given by ____________

A. Darcy Weisbach equation
B. Hazen and William equation
C. Stokes equation
D. Bernoulli’s equation
Answer» D. Bernoulli’s equation
114.

The deviation from the ideal flow of wastewater in the sedimentation tank causes ____________

A. Whirlpool
B. Increase in tank efficiency
C. Short circuiting
D. Coagulation
Answer» D. Coagulation
115.

____ represents the size of sand particle such that 10% of particles are finer than this size.

A. D₀ꓸ₁
B. D₁
C. D₁₀
D. D₁₀₀
Answer» D. D₁₀₀
116.

What is the effective size of Anthracite when used as a filter material?

A. 0.1-0.2mm
B. 0.2-0.4mm
C. 0.4-0.6mm
D. 0.7-0.75mm
Answer» E.
117.

The diameter of the vertical type pressure filter is __________

A. 2-2.5 m
B. 1 m
C. 5 m
D. 10 m
Answer» B. 1 m
118.

Which of the following is the expression of the Carmen equation where symbols have their usual meanings?

A. hf = f* (L/(s *d)) * ((1-e)/e³) * (v²/g)
B. hf = f* (L/(s *d)) * ((1-e)/e³) * (v/g)
C. hf = f* (L/(s *d)) * ((1-e)/e) * (v²/g)
D. hf = f* (L/(s *d)) * ((1-e)/e²) * (v²/g)
Answer» B. hf = f* (L/(s *d)) * ((1-e)/e³) * (v/g)
119.

The sedimentation basin should be made as deep as possible.

A. True
B. False
C. May be True or False
D. Can't say
Answer» C. May be True or False
120.

The slow sand filter is designed for _____________

A. Maximum daily demand
B. Maximum yearly demand
C. Average daily demand
D. Maximum weekly demand
Answer» B. Maximum yearly demand
121.

Which device is used to supply air for the agitation of sand grains during washing of filters?

A. Rate control device
B. Tube settlers
C. Air compressors
D. Flocculator
Answer» D. Flocculator
122.

_______ type of trouble in filter is caused by the released of dissolved air and gases from water.

A. Air binding
B. Clogging
C. Mud balls
D. Jetting
Answer» B. Clogging
123.

What is the frequency of cleaning of a slow sand filter?

A. 1 week
B. 1-3 months
C. 2-3 days
D. 2-3 weeks
Answer» C. 2-3 days
124.

_______ is formed when alum is added to sewage.

A. Acid
B. Floc
C. Salt
D. Base
Answer» C. Salt
125.

______ are formed in filters due to insufficient washing of sand grains.

A. Sand boils
B. Mud balls
C. Clogging
D. Bubbles
Answer» C. Clogging
126.

Range of Displacement efficiency in the plain sedimentation tank is ___________

A. 0.25-0.5
B. 0.1-0.2
C. 0.5-0.8
D. 0.3-0.6
Answer» B. 0.1-0.2
127.

The quantity of water flowing per hour per unit horizontal area is called ________

A. Detention time
B. Flowing through period
C. Displacement time
D. Overflow rate
Answer» E.
128.

The average time required by water to pass through the settling tank is called _______

A. Detention time
B. Flowing through period
C. Time of flow
D. Mean time
Answer» C. Time of flow
129.

Which of the following represents the correct relation between displacement velocity and diameter of the particle?

A. v1 = (8Bg (G-1) d/f)^1/2
B. v1 = (8Bg (G-1) d2/f)²
C. v1 = (8Bg (G-1) d/f)
D. v1 = (8Bg (G-1) d/f)²
Answer» B. v1 = (8Bg (G-1) d2/f)²
130.

The detention period of a rectangular tank is given by _______

A. t0 = LBH/Q
B. t0 = LB/HQ
C. t0 = Q/LBH
D. t0 = HQ/LB
Answer» B. t0 = LB/HQ
131.

Consider the following statement regarding the depth of sand of the rapid gravity filter?i. It should be checked against breakage of flocii. The sand depth should lie between 100-200cmiii. The floc should be attached through the sand bedWhich of the above statement is/are correct?

A. Only i
B. i, ii
C. ii, iii
D. Only ii
Answer» B. i, ii
132.

The area of the filter is 1500. What is the number of beds to be provided?

A. 1
B. 2
C. 3
D. 6
Answer» C. 3
133.

Schmutzdecke acts as an extremely fine meshed straining mat.

A. True
B. False
C. May be True or False
D. Can't say
Answer» B. False
134.

What is the normal value of the detention period adopted in a flocculator for design purpose?

A. 30min
B. 60min
C. 90min
D. 100min
Answer» B. 60min
135.

In which type of settling, sedimentation of discrete particles takes place?

A. Zone settling
B. Compression settling
C. Hindered settling
D. Discrete settling
Answer» E.
136.

In which action of filtration, colloidal particles are removed?

A. Mechanical Straining
B. Sedimentation
C. Biological mechanism
D. Electrolytic action
Answer» C. Biological mechanism
137.

When the loss of the head exceeds the static head, the head becomes _____

A. Positive
B. Negative
C. Constant
D. Zero
Answer» C. Constant
138.

The finer the suspended impurities to be removed ___________

A. Larger will be the sand size
B. Smaller will be the sand size
C. Smaller will be the surface area of sand grains
D. Narrow will be the sand depth of the bed
Answer» C. Smaller will be the surface area of sand grains
139.

What is the settling velocity of the particle in the wastewater if its diameter is 2 * 10⁻³ cm. Given G=2.65, viscosity v=8 * 10⁻³ cm²/Sec?

A. 0.01cm/Sec
B. 0.13cm/Sec
C. 0.24cm/Sec
D. 0.36cm/Sec
Answer» C. 0.24cm/Sec
140.

Rapid sand filters are very efficient in removal of color.

A. True
B. False
C. May be True or False
D. Can't say
Answer» B. False
141.

The thickness of the base material of a rapid sand filter on which filter media are supported is __________

A. 45-60cm
B. 20-80cm
C. 30-75cm
D. 10-30cm
Answer» B. 20-80cm
142.

Detention time for a circular tank is given by _______

A. t = D (D + 0.785H) /Q
B. t = D (0.1D + 0.785H) /Q
C. t = D2 (0.01D + 0.785H)
D. t = D2 (0.01D + 0.785H) /Q
Answer» E.
143.

In which type of filtration problem, layers of gravel are displaced?

A. Clogging
B. Air binding
C. Sand incrustation
D. Sand leakage
Answer» E.
144.

When the Reynolds number is greater than 1.9 but less than 500, the coefficient of drag CD is?

A. CD = 24/R
B. CD = R/24
C. CD = 18.5/R⁰·⁶
D. CD = R⁰·⁶/18.5
Answer» D. CD = R⁰·⁶/18.5
145.

The chemical composition of Chlorinated Copperas is __________

A. Fe₂ (SO₄)₃ + FeCl₃
B. FeSO₄.9H₂O
C. FeSO₄.18H₂O
D. Fe₂ (SO₄)₃
Answer» B. FeSO₄.9H₂O
146.

Alum is effective when pH of water is between ____

A. 8-10
B. 6-8
C. 6.5-8.5
D. 7-9
Answer» D. 7-9
147.

Why Alum is preferred over other coagulants?

A. It is easy to dewater the sludge formed
B. It imparts corrosiveness to water
C. It reduces taste and odor in addition to turbidity
D. The time required for floc formation is less
Answer» D. The time required for floc formation is less
148.

Which gas is released when alum is added to water?

A. Al (OH)₃
B. CaSO₄
C. CO₂
D. Ca (OH)₃
Answer» D. Ca (OH)₃
149.

What indicates the permanent hardness when alum is added to water?

A. Al (OH)₃
B. CaSO₄
C. CO₂
D. Ca (OH)₃
Answer» C. CO₂
150.

The rate of filtration of pressure filtration is ______ l/m²/hour.

A. 1000-5000
B. 5000-10000
C. 6000-8000
D. 6000-15000
Answer» E.