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Focused topic practice

waste water engineering MCQs

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

waste water engineering Mcqs
1. Pick up the correct statement from the following?
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A. All the above

B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated sewage in river

C. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers

D. Solubility of oxygen in sewage is 95% of that of distilled water

2. Dry weather flow is__________________?
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A. Average daily rate of flow

B. Water supply allowance per capita

C. Average monthly rate of flow

D. Average annual rate of flow

3. Which of the following pumps in used to pump sewage solids with liquid sewage without clogging the pump is ?
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A. None of these

B. Centrifugal pump

C. Pneumatic ejector

D. Reciprocating pump

4. For drainage pipes in buildings the test applied before putting them to use, is__________________?
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A. Water test

B. Straightness test

C. Smoke test

D. All the above

5. The pressure exerted by_____________?
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A. Pressure sewers are designed to be safe in tension

B. All the above

C. The internal pressure if any, causes tensile stress in the pipe material

D. The sewage when running full from inside, is called internal pressure

6. Acid regression stage of sludge digestion at a temperature 21C extends over a period of______________?
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A. 30 days

B. 90 days

C. 60 days

D. 15 days

7. Hydraulic mean radius is_______________?
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A. Mean of radii in a pipe line of varying cross -sections

B. Mean radius of sewer

C. Difference in heads between two points in circular pipes

D. Cross-sectional area/wetted perimeter
8. The asbestos cement sewers are_________________?
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A. Susceptible to corrosion by sulphuric acid

B. Not structurally strong to bear large compressive stress

C. Light in weight

D. All the above
9. For a continuous flow type of sedimentation tanks__________________?
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A. Length of the tank is normally kept 4 to 5 times the width

B. Width of the tank is normally kept about 6 m

C. Maximum horizontal flow velocity is limited to 0.3 m/minute

D. All the above
10. For treating the sewage of a large city, you will recommend_________________?
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A. Sedimentation tanks with high rate trickling filters

B. A plant consisting of Imhoff tanks with low rate trickling filters

C. None of these

D. A sedimentation tank and an activated sludge treatment plant
11. The sewer which received discharge from two or more main sewers, is known as_______________?
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A. A trunk sewer

B. A main sewer

C. An intercepting sewer

D. An outfall sewer

12. The drainage area of a town is 12 hectares. Its 40% area is hard pavement ( K = 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas as 30 minutes and using the formula Ps = 900/(t + 60) the maximum run off is__________________?
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A. 0.10 cumec

B. 0.12 cumec

C. 0.15 cumec

D. 0.20 cumec

13. R.M.O. expenses include___________________?
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A. Running expenses

B. Maintenance expenses

C. All the above

D. Operation expenses

14. No treatment of the sewage is given if dilution factor is_____________?
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A. More than 500

B. Less than 150

C. Between 200 to 300

D. Between 150 to 200

15. th or th extra space is left in sewer pipes at maximum discharge for_________________?
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A. Unexpected increase in population

B. Low estimates of the average and maximum flows

C. Large scale infiltration of storm water

D. All the above
16. The rational formula for peak drainage discharge, was evolved by_________________?
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A. Fruhling

B. Kuichling

C. All of these

D. Lloyd David

17. The rainfall at any place may be determined by__________________?
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A. Its intensity

B. All the above

C. Its direction

D. Its frequency

18. The coagulant which is generally not used for treating the sewage, is__________________?
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A. Ferric chloride

B. Ferric sulphate

C. Chlorinated copperas

D. Alum
19. Bottom openings 15 cm 15 cm in the standing baffle wall are provided________________?
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A. 22.5 cm c/c

B. 15 cm c/c

C. 50 cm c/c

D. 30 cm c/c

20. If the flame of a miners safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains_______________?
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A. Methane

B. Hydrogen sulphide

C. Carbon dioxide

D. Oxygen