civil engineering MCQs – Page 224

Practise multiple-choice questions from civil engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

civil engineering Mcqs
4461. Sludge volume index is defined as the ratio of_______________?
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A. percentage of sludge by volume to percentage of total solids by weight

B. percentage of total solids by weight to percentage of sludge by volume

C. percentage of suspended solids by weight to percentage of sludge by volume

D. percentage of sludge by volume to percentage of suspended solids by weight
4462. Which of the following values of pH represents a stronger acid?
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A. 2

B. 5

C. 10

D. 7

4463. The relative stability of a sewage sample, whose dissolved oxygen is same as the total oxygen required to satisfy BOD, is______________?
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A. zero

B. 1

C. infinite

D. 100
4464. Which of the following is not a water borne disease ?
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A. typhoid

B. maleria

C. dysentery

D. cholera

4465. Assertion A : The consumption of water increases with increase in the distribution pressure. Reason R : Higher distribution pressure causes more loss and waste of water. Select your answer according to 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

4466. An egg shaped section of sewer________________?
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A. is more stable than circular section

B. is economical than circular section

C. is easy to construct

D. provides self cleansing velocity at low discharges
4467. 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 20C. The BOD of raw sewage will be___________?
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A. 400 ppm

B. 100 ppm

C. 200 ppm

D. 300 ppm

4468. The population of a town in three consecutive years are 5000, 7000 and 8400 respectively. The population of the town in the fourth consecutive year according to geometrical increase method is________________?
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A. 9500

B. 9800

C. 10920

D. 10100

4469. The design discharge for the separate sewer system shall be taken as_____________?
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A. 3 x DWF

B. equal to dry weather flow (DWF)

C. 6xDWF

D. 2xDWF

4470. The type of valve which is provided to control the flow of water in the distribution system at street corners and where the pipe lines intersect is_______________?
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A. sluice valve

B. check valve

C. safety valve

D. scour valve

4471. If Biochemical oxygen demand (BOD. of a town is 20000 kg/day and BOD per capita per day is 0.05 kg, then population equivalent of town is_________________?
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A. 100000

B. 1000

C. 400000

D. 4000

4472. Air binding phenomena in rapid sand filters occur due to_________________?
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A. higher turbidity in the effluent

B. excessive negative head

C. low temperature

D. mud ball formation

4473. For normal sludge, the value of sludge index for Indian conditions is________________?
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A. 150 to 350

B. 50 to 150

C. 0 to 50

D. 350 to 500

4474. In water treatment, rapid gravity filters are adopted to remove_______________?
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A. dissolved organic substances

B. dissolved solids and dissolved gases

C. bacteria and colloidal solids

D. floating solids and dissolved inorganic solids

4475. The layout of distribution system in which water flows towards the outer periphery is_________________?
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A. radial system

B. ring system

C. dead end system

D. grid iron system

4476. For satisfactory working of a sludge digestion unit, the pH range of digested sludge should be maintained as___________________?
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A. 10.5 to 12.0

B. 8.5 to 10.0

C. 4.5 to 6.0

D. 6.5 to 8.0
4477. The detention period and overflow rate respectively for plain sedimentation as compared to sedimentation with coagulation are generally_______________?
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A. more and less

B. more and more

C. less and more

D. less and less

4478. Which of the following chemical compounds can be used for dechlorination of water ?
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A. chloramines

B. carbon dioxide

C. sulphur dioxide

D. bleaching powder

4479. The effect of increasing diameter of sewer on the self cleansing velocity is_____________?
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A. fluctuating

B. to decrease it

C. to increase it

D. nil

4480. The detention period for oxidation ponds is usually kept as______________?
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A. 24 hours

B. 4-8 hours

C. 3 months

D. 10 to 15 days