61. The maximum discharge of a tube-well is about_________________?
A. 5 litres/sec
B. 50 litres/sec
C. 500 litres/sec
D. 1000 litres/see
✅ The correct answer is option B.
Environmental Engineering MCQs
62. The type of valve, which is provided on the suction pipe in a tube-well, is____________?
A. air relief valve
B. reflux valve
C. pressure relief valve
D. sluice valve
✅ The correct answer is option B.
63. Dissolved oxygen in streams is______________?
A. maximum at noon
B. minimum at noon
C. maximum at midnight
D. same throughout the day
✅ The correct answer is option A.
64. Which of the following methods of analysis of water distribution system is most suitable for long and narrow pipe system ?
A. circle method
B. equivalent pipe method
C. Hardy cross method
D. electrical analysis method
✅ The correct answer is option B.
65. The process of lagooning is primarily a means of________________?
A. reducing the excessive flow in sewers
B. disposing of sludge
C. increasing the capacity of storage re-servoirs
D. increasing flow of sewage through imhoff tanks
✅ The correct answer is option B.
66. The polluted water is one which_______________?
A. contains pathogenic bacteria
B. consists of undesirable substances rendering it unfit for drinking and domestic use
C. is safe and suitable for drinking and domestic use
D. is contaminated
✅ The correct answer is option B.
67. The main disadvantage of cement concrete sewers is________________?
A. less strength
B. difficulty in construction
C. difficulty in transportation due to heavy weight
D. less life
✅ The correct answer is option C.
68. In a BOD test, 1.0 ml of raw sewage was diluted to 100 ml and the dissolved oxygen concentration of diluted sample at the beginning was 6 ppm and it was 4 ppm at the end of 5 day incubation at 20°C. The BOD of raw sewage will be___________?
A. 100 ppm
B. 200 ppm
C. 300 ppm
D. 400 ppm
✅ The correct answer is option B.
69. The phenolic compounds in public water supply should not be more than_______________?
A. 0.1 ppm
B. 0.01 ppm
C. 0.001 ppm
D. 0.0001 ppm
✅ The correct answer is option C.
70. The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of________________?
A. 1 mg/litre
B. 10 mg/litre
C. 100 mg/litre
D. 1000 mg/litre
✅ The correct answer is option B.