environmental engineering MCQs

Practise focused environmental engineering questions with marked answers for exam preparation and subject revision.

environmental engineering Mcqs
1. Average rate of water consumption perhead per day as per Indian Standard is______________?
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A. 200 litres

B. 135 litres

C. 100 litres

D. 165 litres

2. A pipe conveying sewage from plumbing system of a single building to common sewer or point of immediate disposal is called________________?
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A. main sewer

B. house sewer

C. submain sewer

D. lateral sewer

3. Cleaning is done by________________?
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A. back washing in slow sand filters

B. correct answer is

C. scraping and removal in filters rapid sand

D. back washing in rapid sand filters</strong>

E. scraping and removal in filters slow sand
4. The rate of BOD exerted at any time is_____________?
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A. directly proportional to BOD satisfied

B. inversely proportional to BOD re-maining

C. directly proportional to BOD remain-ing

D. inversely proportional to BOD satisfied

5. For a country like India, where rainfall is mainly confined to one season, the suitable sewerage system will be________________?
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A. partially separate system

B. combined system

C. separate system

D. partially combined system

6. The suitable layout of distribution system for a city with roads of rectangular pattern is______________?
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A. ring system

B. dead end system

C. radial system

D. grid iron system
7. The percentage of chlorine in fresh bleaching powder is about________________?
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A. 30 to 35

B. 40 to 50

C. 10 to 15

D. 20 to 25

8. The suitable method of forecasting population for a young and rapidly increasing city is_________________?
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A. arithmetical increase method

B. incremental increase method

C. geometrical increase method

D. graphical method

9. The method of analysis of distribution system in which the domestic supply is neglected and fire demand is considered is________________?
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A. circle method

B. electrical analysis method

C. equivalent pipe method

D. Hardy cross method

10. The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is____________________?
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A. pressure relief valve

B. reflux valve

C. air relief valve

D. sluice valve

11. Select the correct statement?
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A. 5 day BOD is greater than 4 day BOD keeping other conditions same

B. 5 day BOD is the ultimate BOD

C. BOD does nof depend on time

D. 5 day BOD is less than 4 day BOD keeping other conditions same
12. If the average daily consumption of a city is 100,000 m3, the maximum daily consumption on peak hourly demand will be_______________?
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A. 270000 m3

B. 150000m3

C. 180000m3

D. 100000m3

13. The velocity of flow of water in a sedimentation tank is about__________________?
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A. 15 to 30 cm/minute

B. 15 to 30 cm/sec.

C. 15 to 30 cm/hour

D. 5 to 10 cm/sec.

14. The polluted water is one which_______________?
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A. contains pathogenic bacteria

B. consists of undesirable substances rendering it unfit for drinking and domestic use

C. is contaminated

D. is safe and suitable for drinking and domestic use

15. The settling velocity of a particle in a sedimentation tank increases if_________________?
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A. the depth of tank is decreased

B. particle size is decreased

C. none of the above

D. the surface area of tank is increased

16. When there is no recirculation of sewage, then recirculation factor is_______________?
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A. 0

B. 1

C. infinity

D. none of the above

17. Which of the following retards the self purification of stream ?
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A. higher temperature

B. sunlight

C. none of the above

D. satisfying oxygen demand

18. The amount of coagulant needed for coagulation of water increases with_______________?
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A. correct answer is?

B. decrease in turbidity of water

C. increase in turbidity of water

D. decrease in temperature of water</strong>

E. increase in temperature of water

19. As compared to rapid sand filters, slow sand filters give______________?
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A. slower filtration rate

B. lesser efficiency in removal of bacteria

C. higher efficiency in removal of bacteria </strong>

D. higher filtration rate

E. correct answer is?

20. The major disadvantage of lime soda process of water softening is that_________________?
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A. huge amount of precipitate is formed which creates a disposal problem

B. the effluent cannot be reduced to zero hardness

C. it is unsuitable for turbid and acidic water

D. it is unsuitable for softening the water of excessive hardness

21. Disinfection efficiency is________________?
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A. increased at higher pH value of water

B. highest at pH value equal to 7

C. unaffected by pH value of water

D. reduced at higher pH value of water
22. Chlorine demand of water is equal to________________?
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A. sum of applied and residual chlorine

B. residual chlorine

C. applied chlorine

D. difference of applied and residual chlorine
23. The depression of water table in a well due to pumping will be maximum_______________?
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A. close to the well

B. re R is the radius of influence

C. at a distance R/2 from the well

D. none of the above

E. at a distance R from the well

24. A sewer that receives the discharge of a number of house sewers is called________________?
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A. intercepting sewer

B. submain sewer

C. lateral sewer

D. house sewer

25. The type of sewer which is suitable for both combined and separate system is_____________?
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A. circular sewer

B. horse-shoe type sewer

C. egg shaped sewer

D. semi-elliptical sewer

26. The working conditions in imhoff tanks are_______________?
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A. aerobic in lower compartment and anaerobic in upper compartment

B. aerobic only

C. anaerobic in lower compartment and aerobic in upper compartment

D. anaerobic only

27. Most of the bacteria in sewage are______________?
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A. saprophytic

B. parasitic

C. anaerobic

D. pathogenic

28. As compared to higher pH values, the contact period required for efficient chlorination at lower pH values is___________________?
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A. smaller

B. same

C. none of the above

D. larger

29. Ground water is usually free from________________?
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A. suspended impurities

B. dissolved impurities

C. both suspended and dissolved impurities

D. none of the above

30. If the total hardness of water is greater than its total alkalinity, the carbonate hardness will be equal to________________?
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A. total hardness total alkalinity

B. total alkalinity

C. total hardness

D. non carbonate hardness

31. Generally the detention period for grit chambers is kept as_______________?
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A. 12 hours

B. 2-4 hours

C. 1 minute

D. 5 minutes

32. Alum as a coagulant is found to be most effective when pH range of water is______________?
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A. 2 to 4

B. 8 to 10

C. 4 to 6

D. 6 to 8
33. The pathogens can be killed by_______________?
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A. chlorination

B. none of the above

C. nitrification

D. oxidation

34. The ratio of 5 day BOD to ultimate BOD is about_______________?
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A. 3-Jan

B. 4-Mar

C. 1

D. 2/3
35. Corrosion in concrete sewers is caused by______________?
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A. dissolved oxygen

B. chlorine

C. nitrogen

D. septic conditions
36. Which of the following compounds is widely used for algae control ?
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A. sodium sulphate

B. copper sulphate

C. sodium chloride

D. calcium chloride

37. The maximum discharge of a tube-well is about_________________?
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A. 50 litres/sec

B. 500 litres/sec

C. 1000 litres/see

D. 5 litres/sec

38. Facultative bacteria are able to work in________________?
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A. presence of oxygen only

B. absence of oxygen only

C. presence of water

D. presence as well as in absence of oxygen
39. Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters. Reason R : The sand used in slow sand filters is finer than that in rapid sand filters. Select your answer based on the coding system given below?
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A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true but R is not the correct explanation of A

C. A is true but R is false

D. A is false but R is true

40. The design discharge for the combined sewer system shall be taken as________________?
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A. rainfall + 2 DWF

B. rainfall + 6 DWF

C. equal to rainfall

D. rainfall + DWF

41. Percentage of bacterial load that can be removed from water by the process of plain sedimentation is about_______________?
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A. 100

B. 75

C. 10 to 25

D. 50

42. The hydraulic mean depth (HMD. for an egg-shaped sewer flowing two-third full is_______________?
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A. none of the above

B. less than HMD when flowing full

C. greater than HMD when flowing full

D. equal to HMD when flowing full

43. The disinfection efficiency of chlorine increases by_______________?
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A. decreasing the time of contact

B. decreasing the temperature of water

C. increasing the temperature of water</strong>

D. correct answer is ?

E. only (1)

F. both (1) and (2)

44. The most common cause of acidity in water is_______________?
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A. nitrogen

B. oxygen

C. carbon dioxide

D. hydrogen

45. Residual chlorine in water is determined by________________?
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A. starch iodide method

B. orthotolidine method

C. both (A) and (B)

D. none of the above

46. The suitable method for disinfection of swimming pool water is________________?
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A. lime treatment

B. by using potassium permanganate

C. chlorination

D. ultra violet rays treatment
47. The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of________________?
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A. 100 mg/litre

B. 1000 mg/litre

C. 1 mg/litre

D. 10 mg/litre
48. The suitable system of sanitation for area of distributed rainfall throughout the year with less intensity is_________________?
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A. partially separate system

B. combined system

C. separate system

D. partially combined system

49. The rate of filtration in slow sand filters in million litres per day per hectare is about_____________?
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A. 50 to 60

B. 100 to 150

C. 1400 to 1500

D. 500 to 600

50. The minimum and maximum diameters of sewers shall preferably be_________________?
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A. 15 cm and 300 cm

B. 15 cm and 100 cm

C. 30 cm and 450 cm

D. 60 cm and 300cm