380+ Environmental Engineering Solved MCQs

Environmental engineering is a field of engineering that deals with the application of scientific and engineering principles for the protection of the environment and the health of the general public. Environmental engineers work to identify and assess the environmental impacts of human activities and design solutions to prevent or mitigate those impacts. They may work on a wide range of issues, such as air and water pollution, waste management, and sustainable development. Some common tasks of an environmental engineer include conducting environmental assessments, designing and implementing pollution control systems, and developing strategies for sustainable resource use.
1.

Which system of collection of sewage is a dry system?

A. conservancy system
B. biological digestion
C. incernation
D. water carriage system
Answer» A. conservancy system
2.

After how many years, night soil gives good quality manure?

A. 1
B. 5
C. 10
D. 14
Answer» A. 1
3.

Conservancy system is a highly unhygienic system, causing insanitary conditions.

A. true
B. false
Answer» A. true
4.

Which of the following is not correct regarding conservancy system?

A. high maintenance cost
B. highly unhygienic system
C. independent of labour
D. chances of epidemic
Answer» C. independent of labour
5.

Which system of collection of sewage is called a dry system?

A. conservancy system
B. biological digestion
C. incernation
D. water carriage system
Answer» A. conservancy system
6.

is a method where water is used as a medium for the flow of sewage from its production of the treatment unit.

A. conservancy system
B. biological digestion
C. incernation
D. water carriage system
Answer» D. water carriage system
7.

The water carriage system is a hygienic system without any bad smell.

A. true
B. false
Answer» A. true
8.

Which of the following is correct regarding water carriage system?

A. chances of the epidemic is there
B. foul smell is produced
C. does not cause pollution
D. highly dependent on labours
Answer» C. does not cause pollution
9.

Which of the following is an advantage of a separate water carriage system?

A. get choked easily
B. difficult to clean the sewer
C. two sets of sewer are used
D. the more uniform character of sewage
Answer» D. the more uniform character of sewage
10.

Which of the following is a disadvantage of a separate water carriage system?

A. low installation charge
B. no loads on treatment units
C. lesser air contact with small sized sewer
D. provision of the automatic flushing tank is not required
Answer» C. lesser air contact with small sized sewer
11.

provides only one sewer to carry both foul sewage and rainwater.

A. separate water carriage system
B. combined water carriage system
C. partially combined water carriage system
D. conservancy system
Answer» B. combined water carriage system
12.

Which of the following is an advantage of the combined water carriage system?

A. there is more air in large sewer
B. there is the inclusion of storm water
C. there is difficulties in ventilation of large sewer
D. overflowing of sewer
Answer» A. there is more air in large sewer
13.

Which of the following is incorrect regarding partially combined water carriage system?

A. the sewers are of reasonable size
B. there is choking of sewer
C. the storm water increases load on treatment units
D. the storm water increases the cost of pumping
Answer» B. there is choking of sewer
14.

The choice of combined water carriage system does not depend on

A. space consideration
B. even rainfall pattern
C. steep topography
D. pumping requirements
Answer» C. steep topography
15.

is the flow through sewers available during non-rainfall period.

A. gradually varied flow
B. rapidly varied flow
C. dry weather flow
D. storm water flow
Answer» C. dry weather flow
16.

is the additional flow occurring during rainy season.

A. gradually varied flow
B. rapidly varied flow
C. dry weather flow
D. storm water flow
Answer» D. storm water flow
17.

Which flow is also called as sanitary sewage?

A. dry weather flow
B. storm weather flow
C. uniform flow
D. non uniform flow
Answer» A. dry weather flow
18.

Which of the following factor does not effect the dry weather flow?

A. rate of water supply
B. temperature conditions
C. population growth
D. infiltration of ground water
Answer» B. temperature conditions
19.

The sewer should be designed for a minimum of              litres of waste water per capita per day.

A. 50
B. 100
C. 150
D. 1000
Answer» C. 150
20.

is the process in which ground water unfiltrate into the sewers.

A. exfiltration
B. infiltration
C. filtration
D. osmosis
Answer» B. infiltration
21.

                 is the process which indicates the flow of waste water from the sewer into the ground.

A. exfiltration
B. infiltration
C. filtration
D. osmosis
Answer» A. exfiltration
22.

The peaking factor is defined by

A. peak flow * average flow
B. peak flow – average flow
C. peak flow + average flow
D. peak flow / average flow
Answer» D. peak flow / average flow
23.

The peaking factor is directly proportional to the population of the city.

A. true
B. false
Answer» B. false
24.

The wet weather flow is also known by

A. minimum sewage flow
B. maximum sewage flow
C. storm water flow
D. average rate of flow
Answer» C. storm water flow
25.

Which of the following surface has a maximum Kuichling’s impermeability factor?

A. gravel road
B. water tight roof surface
C. unpaved surface
D. macadamized road ways
Answer» B. water tight roof surface
26.

The expression of the Chezy’s formula is given by                          

A. v = c/rs
B. v = crs2
C. v = c (rs)1/2
D. v = c/ (rs)1/2
Answer» C. v = c (rs)1/2
27.

Which of the following is the expression of the Manning’s formula?

A. $$$V = R^{1/2}S^{1/2}/N$$$
B. $$$V = R^{2/3}S^{2}/N$$$
C. $$$V = R^{2/3}S^{1/2}/N$$$
D. $$$V = R^{2/3}S^{1/2}$$$
Answer» C. $$$V = R^{2/3}S^{1/2}/N$$$
28.

               is the velocity at which the solid matter in sewage remained in suspended form.

A. settling velocity
B. self cleansing velocity
C. mean velocity
D. non scouring velocity
Answer» B. self cleansing velocity
29.

Primary treatment of sewage consists of removal of

A. large suspended organic solids
B. oil and grease
C. sandand grit
D. floating materials
Answer» A. large suspended organic solids
30.

The most widely used pumps for sewage lifting is

A. centrifugal pummp
B. reciprocating pump
C. pneumatic ejector
D. air pressure pump
Answer» A. centrifugal pummp
31.

Drop man holes are generally provided in sewers for

A. industrial reas
B. large township
C. hilly townships
D. cities in plains
Answer» C. hilly townships
32.

The pollution zones in the river are divided into how many types?

A. 3
B. 4
C. 6
D. 8
Answer» B. 4
33.

In which pollution zone of the river, growth of algae reappear?

A. zone of degradation
B. zone of recovery
C. zone of active decomposition
D. zone of clean water
Answer» B. zone of recovery
34.

In which pollution zone of the river, the dissolved oxygen reduced to 0?

A. zone of degradation
B. zone of recovery
C. zone of clean water
D. zone of active decomposition
Answer» D. zone of active decomposition
35.

Which is the third zone of pollution in the river?

A. zone of recovery
B. zone of degradation
C. zone of clean water
D. zone of active decomposition
Answer» A. zone of recovery
36.

What is yellow curve represents in the following figure?

A. deoxygenation curve
B. reoxygenation curve
C. oxygen sag curve
D. equilibrium concentration of oxygen
Answer» A. deoxygenation curve
37.

Which of the following is represented b the green curve in the above figure?

A. deoxygenation curve
B. reoxygenation curve
C. oxygen sag curve
D. equilibrium concentration of oxygen
Answer» B. reoxygenation curve
38.

The maximum deficiency of dissolved oxygen is represented by                          

A. dotted blue line
B. green curve
C. yellow curve
D. violet curve
Answer» A. dotted blue line
39.

Which of the following represents the oxygen sag curve in the following figure?

A. dotted blue line
B. green curve
C. yellow curve
D. red curve
Answer» D. red curve
40.

The reoxygenation constant at temperature ‘T’ is expressed by

A. krt = kr20 (1.016)t
B. krt = kr20 (1.047) t-20
C. krt = kr20 (1.016)t-20
D. krt = kr20 (1.047)t
Answer» C. krt = kr20 (1.016)t-20
41.

The minimum spacing between the bars on fine screen is                          

A. 0.3mm
B. 0.9mm
C. 1.5mm
D. 0.5mm
Answer» C. 1.5mm
42.

The spacing between the bars in racks is                          

A. 30mm
B. 50mm
C. 70mm
D. 90mm
Answer» B. 50mm
43.

Screens are inclined to the direction of flow to                          

A. increase the flow velocity
B. increase the opening area
C. decrease the flow velocity
D. increase the head loss
Answer» C. decrease the flow velocity
44.

The maximum spacing between the bars in medium screen is

A. 40mm
B. 50mm
C. 70mm
D. 90mm
Answer» A. 40mm
45.

What is the maximum capacity of medium screen in collecting solids?

A. 30l
B. 40l
C. 50l
D. 90l
Answer» D. 90l
46.

The design velocity of flow of a detritus tank is                          

A. 1m/sec
B. 1.2m/sec
C. 0.9m/sec
D. 0.5m/sec
Answer» C. 0.9m/sec
47.

Which of the following device is used for the removal of oil and grease?

A. skimming tank
B. grit chambers
C. tube settlers
D. flocculator
Answer» A. skimming tank
48.

How many types of settling are there in the sedimentation tank?

A. 3
B. 4
C. 5
D. 6
Answer» B. 4
49.

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

A. zone settling
B. compression settling
C. hindered settling
D. discrete settling
Answer» D. discrete settling
50.

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» C. stokes equation
51.

In which type of settling, settling of particles takes place by the contact of impurities with each other present in wastewater?

A. flocculent settling
B. hindered settling
C. compression settling
D. discrete settling
Answer» C. compression settling
52.

In which settling type, dilute suspension of particles takes place?

A. zone settling
B. compression settling
C. hindered settling
D. discrete settling
Answer» C. hindered settling
53.

What is the settling velocity of the particle in the wastewater 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» B. 0.13cm/sec
54.

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

A. detention time
B. flow through period
C. time of flow
D. mean time
Answer» B. flow through period
55.

In preliminary treatment of sewage, the operation which takes place, is

A. removal of fine suspended particles
B. removal of fine dissolved organic material
C. removal of lighter floating material
D. removal of harmful bacterias and other organisms
Answer» C. removal of lighter floating material
56.

How many types of aerators are commonly used in the treatment of wastewater?

A. 2
B. 3
C. 4
D. 5
Answer» A. 2
57.

The detention period of detritus tank is

A. 40 seconds
B. 1 minute
C. 3 minute
D. 1 hour
Answer» C. 3 minute
58.

How many types of trickling filters are used in sewage treatment?

A. 1
B. 5
C. 3
D. 2
Answer» D. 2
59.

The depth of the filter media of intermittent filter is                        

A. 45cm
B. 60cm
C. 20cm
D. 25cm
Answer» B. 60cm
60.

Which of the following filter is used in the anaerobic treatment of sewage?

A. intermittent sand
B. trickling filter
C. contact filter
D. biological filter
Answer» D. biological filter
61.

The maximum size of filter media of a percolating filter is

A. 10mm
B. 25mm
C. 60mm
D. 75mm
Answer» D. 75mm
62.

The recirculation ratio for the low rate trickling filter is                        

A. 1
B. 2
C. 3
D. 0
Answer» D. 0
63.

The BOD after the filtration of sewage from the low rate trickling filter is

A. 40-50%
B. 80-90%
C. 70-80%
D. 90-99%
Answer» B. 80-90%
64.

The efficiency of a percolating filter is given by                        

A. 100/(1+0.0044 (??))
B. 100/(1+0.044 (??) 1/2)
C. 100/(1+0.44 (??) 1/2)
D. 100/(1+0.0044 (??) 1/2)
Answer» D. 100/(1+0.0044 (??) 1/2)
65.

The organic loading in low rate trickling filter is 900 kg/hectare- meter/day. What is the efficiency of the filter?

A. 0.431
B. 0.883
C. 0.0704
D. 0.83
Answer» B. 0.883
66.

The color of the secondary sludge produced from the high rate trickling filter is                        

A. gray
B. black
C. brown
D. green
Answer» C. brown
67.

               is the ratio of volume of recirculated sewage to the raw sewage.

A. recirculation factor
B. recirculation ratio
C. food to mass ratio
D. bod
Answer» B. recirculation ratio
68.

The size of filter media in a high rate trickling filter is                        

A. 10-20mm
B. 34-68mm
C. 25-60mm
D. 20-50mm
Answer» C. 25-60mm
69.

Which of the following is called as air diffusion method?

A. activated sludge aeration
B. diffused air aeration
C. mechanical aeration
D. combined aeration
Answer» B. diffused air aeration
70.

The maximum depth of aeration tank used in activated sludge process is

A. 1m
B. 2m
C. 4.5m
D. 5.5m
Answer» C. 4.5m
71.

Which type of reactor is used for mixing chemicals in water treatment?

A. continuous reactor
B. batch reactor
C. plug flow reactor
D. fixed bed reactor
Answer» B. batch reactor
72.

Which reactors are characterized by non- continuous reactions?

A. plug flow reactor
B. continuous reactor
C. batch reactor
D. fluidized bed reactor
Answer» C. batch reactor
73.

SBR is a type of                  

A. aerobic process
B. activated sludge process
C. anaerobic process
D. chemical process
Answer» B. activated sludge process
74.

How is mixing done in SBR?

A. manual
B. mechanical
C. air stripping
D. agitation by air
Answer» B. mechanical
75.

In which stage of the SBR is aeration performed?

A. first
B. second
C. third
D. fourth
Answer» B. second
76.

Which of the following is an anaerobic process for treating sewage?

A. oxidation pond
B. imhoff tank
C. oxidation ditch
D. rotating biological contactors
Answer» B. imhoff tank
77.

The minimum design depth of oxidation pond is                        

A. 0.3m
B. 0.5m
C. 1m
D. 1.5m
Answer» C. 1m
78.

The detention period of oxidation pond is

A. 12-36 hours
B. 4 hours
C. 10-20 days
D. 30-60 seconds
Answer» C. 10-20 days
79.

The maximum BOD removal efficiency of an oxidation pond is                        

A. 0.9
B. 0.68
C. 0.7
D. 0.8
Answer» A. 0.9
80.

What is the minimum depth of water to be kept in the oxidation pond?

A. 0.3m
B. 0.5m
C. 1 m
D. 1.5m
Answer» C. 1 m
81.

What is the shape of the oxidation ditch?

A. square
B. rectangular
C. circular
D. oval
Answer» D. oval
82.

The ditch is lined by                layer.

A. brick
B. cement
C. permeable
D. impermeable
Answer» D. impermeable
83.

What is the range of MLSS concentration in oxidation ditch?

A. 500-1000 mg/l
B. 1000-2000 mg/l
C. 2000-4000 mg/l
D. 3000-5000 mg/l
Answer» D. 3000-5000 mg/l
84.

Which of the following process is not adopted in oxidation ditches?

A. adsorption
B. desorption
C. oxidation
D. decomposition
Answer» B. desorption
85.

The disposal of sewage from the septic tank is done by which of the following?

A. clarifier
B. soak pit
C. aerated lagoon
D. lamp holes
Answer» B. soak pit
86.

The detention period of a septic tank is

A. 2 hours
B. 12-36 hours
C. 4 hours
D. 1 week
Answer» B. 12-36 hours
87.

The concentration of biodegradable organic matter after the septic tank is

A. 50ppm
B. 100ppm
C. 200ppm
D. 75ppm
Answer» C. 200ppm
88.

What is the maximum design flow of sewage in a septic tank?

A. 70 liters per person per day
B. 100 liters per person per day
C. 30 liters per person per day
D. 40 liters per person per day
Answer» A. 70 liters per person per day
89.

Which of the following is not the method of disposal of sewage from septic tank?

A. upflow anaerobic filter
B. soil absorption system
C. vacuum filter
D. biological filters
Answer» C. vacuum filter
90.

The minimum depth of septic tank as per design consideration is

A. 1.8m
B. 1m
C. 1.2m
D. 1.5m
Answer» C. 1.2m
91.

The efficiency of a percolating filter is given by                        

A. 100/(1+0.0044 (μ))
B. 100/(1+0.044 (μ) 1/2)
C. 100/(1+0.44 (μ) 1/2)
D. 100/(1+0.0044 (μ) 1/2)
Answer» D. 100/(1+0.0044 (μ) 1/2)
92.

Turbidity of water is usually measured in terms of

A. Sodium scale
B. Silica scale
C. Cobalt scale
D. Platinum scale
E. Calcium scale
Answer» B. Silica scale
93.

Which of the following pollutant affects lungs?

A. Silica
B. Benzene
C. Lead
D. Aldrin
E. None of the above
Answer» A. Silica
94.

Black holes are celestial bodies which

A. Have strong magentic field
B. Have strong electrical field
C. Do not allow any light to escape outside
D. Are self luminous bodies
E. Green
Answer» C. Do not allow any light to escape outside
95.

The emission of carbon monoxide in automobile exhaust will be low when the vehicle is

A. idling
B. accelerating
C. cruising at low speeds
D. cruising at high speeds
E. None of the above
Answer» D. cruising at high speeds
96.

Temporary hardness in water in caused by salts like

A. Sulphates
B. Nitrates
C. Chlorides
D. Carbonates
E. All of the above
Answer» D. Carbonates
97.

The colour of water is measured

A. In ferms of pH value
B. In terms of degree of hardness
C. In terms of platinum cobalt scale
D. ppm of dissolved solids
E. None of the above
Answer» C. In terms of platinum cobalt scale
98.

Air pollutants common to urban environments are

A. sulphur dioxide
B. particulate matter
C. Hydrocarbons
D. All of the above
E. None of the above
Answer» D. All of the above
99.

Ionisation chamber can be used for the detection of all of the following EXCEPT

A. beta rays
B. X-rays
C. gamma rays
D. Alpha rays
E. None of the above
Answer» D. Alpha rays
100.

Which of the following is used in the recently developed technology for communication?

A. Optical fibre
B. Glass fibre
C. Nylon fibre
D. Quartz fibre
E. None of these
Answer» A. Optical fibre
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