Explore topic-wise MCQs in Environmental Engineering.

This section includes 112 Mcqs, each offering curated multiple-choice questions to sharpen your Environmental Engineering knowledge and support exam preparation. Choose a topic below to get started.

1.

By aeration process, dissolved iron is oxidized into ____________

A. Ferrous oxide
B. Ferric oxide
C. Ferrous hydroxide
D. Ferric hydroxide
Answer» C. Ferrous hydroxide
2.

In which process, the fluoride content of water is raised?

A. Chlorination
B. Fluoridation
C. Defluoridation
D. Flocculation
Answer» C. Defluoridation
3.

At which temperature, the bone is calcinated during defluoridation with calcium phosphate?

A. 100-200°C
B. 200-300°C
C. 400-600°C
D. 500-800°C
Answer» D. 500-800°C
4.

In which desalination process, the cooling of sea water is done to obtain fresh water?

A. Distillation
B. Electro-dialysis
C. Reverse osmosis
D. Freezing
Answer» E.
5.

Activated carbon can be applied to raw water ______ treatment process.

A. During
B. Ahead of
C. Before
D. After
Answer» C. Before
6.

Removal of manganese from water takes place at a pH of ______

A. 1.5
B. 3
C. 6
D. 9.4
Answer» E.
7.

The presence of Sulfate iron in the water results in ____________

A. Odorless water
B. Acidity in water
C. Colorless water
D. Growth of crenothrix in water mains
Answer» C. Colorless water
8.

Which of the following is used for the control of taste and odor in water?

A. Sedimentation
B. Coagulation
C. Filtration
D. Activated carbon
Answer» E.
9.

In Electro-dialysis, the electric energy which required is _____________

A. Directly proportional to cation permeable membrane
B. Directly proportional to anion permeable membrane
C. Directly proportional to salt concentration
D. Inversely proportional to salt concentration
Answer» D. Inversely proportional to salt concentration
10.

Which of the following is not a property of activated carbon?

A. It is impermeable
B. It has many carbon atoms with free valencies
C. It is available in granular as well as powder form
D. It has a prolonged suspension
Answer» B. It has many carbon atoms with free valencies
11.

The thickness of the activated carbon filter bed is ____________

A. 10-20cm
B. 30-80cm
C. 75-100cm
D. 40-50cm
Answer» D. 40-50cm
12.

_______ is produced by passing a carbonaceous material through a heating mechanism at high temperature.

A. Potassium per-manganate
B. Potassium dichromate
C. Activated carbon
D. Iodine
Answer» D. Iodine
13.

The pressure freezing process works on the vacuum free vapor compression principle.

A. True
B. False
C. May be True or False
D. Can't say
Answer» C. May be True or False
14.

One cubic metre of bone can treat how much quantity of water containing 3.5 ppm of fluoride?

A. 10m³
B. 100m³
C. 1000m³
D. 10000m³
Answer» C. 1000m³
15.

Which of the following is not a type of distillation plant?

A. Vertical tube evaporator
B. Multistage flash evaporator
C. Tube settler
D. Multi-effect multistage flash evaporator
Answer» D. Multi-effect multistage flash evaporator
16.

Which material is used for removing fluorides from hard water containing 3ppm of fluorides?

A. Lime
B. Copper sulfate
C. Synthetic tri-calcium phosphate
D. Bone charcoal
Answer» B. Copper sulfate
17.

The reddish tinge in the water is due to the presence of ____________

A. Zinc
B. Copper
C. Iron
D. Manganese
Answer» D. Manganese
18.

Organic contaminants are removed from the water by the process of ______

A. Water softening
B. Demineralization
C. Absorption
D. Adsorption
Answer» E.
19.

What is the size of the coarse screen used in pretreatment of water?

A. 25mm
B. 50mm
C. 75mm
D. 100mm
Answer» B. 50mm
20.

Which process of water treatment is done to avoid floating debris, branches, trees or other large particles suspended in water?

A. Screening
B. Aeration
C. Primary sedimentation
D. Secondary sedimentation
Answer» B. Aeration
21.

Which of the following is not used for defluoridation?

A. Calcium phosphate
B. Copper sulfate
C. Alum
D. Bone charcoal
Answer» C. Alum
22.

Aswan high dam is situated in

A. China
B. Egypt
C. America
D. Europe
Answer» C. America
23.

When small amounts of iron and manganese are present in water, they are removed by ____________

A. Aeration
B. Coagulation
C. Manganese zeolite
D. Filtration
Answer» D. Filtration
24.

The fluoride concentration for prevention of dental caries is ____________

A. 1mg/l
B. 2mg/l
C. 3mg/l
D. 4mg/l
Answer» B. 2mg/l
25.

In which desalination process, solar energy is used?

A. Reverse osmosis
B. Freezing
C. Electro-dialysis
D. Solar evaporation
Answer» E.
26.

The thickness of the layers of filter sand of zeolite softener is ____________

A. 20cm
B. 30cm
C. 40cm
D. 100cm
Answer» E.
27.

When activated carbon is applied at more than one point, then it is called ________

A. Dual treatment
B. Split treatment
C. Sludge treatment
D. Carbonaceous treatment
Answer» C. Sludge treatment
28.

Which of the following statement is wrong regarding hard water?

A. It causes more consumption of soap in laundry work
B. It causes difficulties in the manufacturing process
C. It increases the taste of food
D. It causes the formation of scales on the boilers
Answer» D. It causes the formation of scales on the boilers
29.

The temperature at which the softening of water takes place by lime soda process is ____________

A. 10°-21°C
B. 20°-30°C
C. 39°-45°C
D. 90°C
Answer» B. 20°-30°C
30.

The permanent hardness can be removed by adding lime and soda.

A. True
B. False
C. May be True or False
D. Can't say
Answer» B. False
31.

The chemical formula of Permutit is ____________

A. SiOAl₂O₃Na₂O
B. SiO₂Al₂O₃Na₂O
C. SiO₂Al₂O₃NaO
D. SiO₃Al₂O₃Na₂O
Answer» C. SiO₂Al₂O₃NaO
32.

The color of the artificial zeolite permutit is ____________

A. Grey
B. Yellow
C. Green
D. White
Answer» E.
33.

Natural zeolite is mainly processed from ____________

A. White sand
B. Green sand
C. Grey sand
D. Red sand
Answer» C. Grey sand
34.

Permutit has an exchange value of ________ grams of hardness per m³ of zeolite.

A. 10,000
B. 20,000-30,000
C. 35,000-40,000
D. 40,000-50,000
Answer» D. 40,000-50,000
35.

In which process of water softening, the chemicals are added to remove hardness from water?

A. Lime soda process
B. Zeolite process
C. Boiling
D. Demineralization process
Answer» B. Zeolite process
36.

Zeolites are complex compound of ____________

A. Aluminium and lime
B. Silica and soda
C. Aluminium, silica and soda
D. Lime and soda
Answer» D. Lime and soda
37.

The sludge in water softening accelerator is deposited at ____________

A. Sedimentation tank
B. Reaction zone
C. Concentrator
D. Secondary mixing zone
Answer» D. Secondary mixing zone
38.

Poor sanitation is an increasing problems of

A. South America and Africa
B. Middle East
C. Asia
D. All of these
Answer» E.
39.

Hot and wet climate are the best condition to grow

A. Plants
B. Animals
C. Insects, Bacteria, viruses
D. All of these
Answer» E.
40.

Softening chemicals, lime and soda do not depend on ____________

A. Free carbon dioxide present
B. Non carbonate hardness
C. Total magnesium
D. Carbonate hardness
Answer» E.
41.

What is the pH at which recarbonation should be done?

A. 7
B. 4.5
C. 8.2
D. 9.5
Answer» E.
42.

Which form of solute stabilization occurs when water passes through limestone?

A. Chlorination
B. Liming
C. Re-carbonation
D. Super-chlorination
Answer» C. Re-carbonation
43.

Solids are removed from the water by which of the following unit operation?

A. Inter facial contact
B. Solid stabilization
C. Ion transfer
D. Solids transfer
Answer» E.
44.

In which type of aerator, the flow of water is divided into fine streams and small droplets?

A. Cascade aerator
B. Inclined apron aerator
C. Spray aerator
D. Gravel bed aerator
Answer» B. Inclined apron aerator
45.

Identify the incorrect statement regarding aeration process.

A. It removes taste and odor
B. It increases the dissolved oxygen content of water
C. It increases the carbon dioxide content of water
D. It is used for mixing chemicals with water
Answer» D. It is used for mixing chemicals with water
46.

The head loss through screen depends on _______________

A. Shape of screen elements
B. Open area, block area
C. Approach velocity
D. Nature of their construction, approach velocity
Answer» E.
47.

Which of the following desalination method is more suitable for brackish water than sea water?

A. Distillation
B. Solar evaporation
C. Reverse osmosis
D. Freezing
Answer» D. Freezing
48.

What concentration of iron and manganese will cause unpleasant taste and odor of water?

A. 1ppm
B. 2ppm
C. 3ppm
D. >3ppm
Answer» E.
49.

Which of the following is the best evaporative desalinating method?

A. Vertical tube evaporator
B. Multistage flash evaporator
C. Tube settler
D. Multi-effect multistage flash evaporator
Answer» C. Tube settler
50.

The number of stages involved in the desalination using a multistage flash evaporator is _________________

A. 20
B. 38
C. 49
D. 69
Answer» E.