civil engineering MCQs – Page 248

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 Review each marked answer and report any item that may be outdated or unclear.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
4941. The normal values of over flow rates for secondary sedimentation tanks, ranges between__________________?
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A. 40,000 to 50,000 litres/sqm/day

B. 25,000 to 35,000 litres/sqm/day

C. 80,000 to 10,000 litres/sqm/day

D. 50,000 to 60,000 litres/sqm/day

4942. Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to_______________?
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A. Carbonaceous demand

B. First stage demand

C. Initial demand

D. All of these
4943. If the peak discharge of a storm water drain (S.W. Drain) is expected to exceed 150 cumecs, the free board to be provided, is_________________?
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A. 100 cm

B. 80 cm

C. 50 cm

D. 90 cm

4944. The normal value of over flow rates for plain primary sedimentation tanks, ranges between________________?
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A. 25,000 to 35,000 litres/sqm/day

B. 80,000 to 100,000 litres/sqm/day

C. 50,000 to 60,000 litres/sqm/day

D. 40,000 to 50,000 litres/sqm/day
4945. For trunk and out-fall, the type of sewers generally used, is_____________________?
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A. Horse shoe shaped

B. Circular shaped

C. Standard egg shaped

D. Parabolic shaped

4946. The standard B.O.D. of water is taken for_________________?
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A. 2 days

B. 5 days

C. 1 day

D. 3 days

4947. In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is_____________________?
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A. 20

B. 5

C. 10

D. 15

4948. Pick up the correct statement from the following?
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A. All the above

B. Only very fresh sewage contains some dissolved oxygen

C. The solubility of oxygen in sewage is 95% that is in distilled water

D. In treated sewage, 4 ppm of D.O. is essential

4949. During purification process of sewage the gas given off, is________________?
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A. Hydrogen

B. Ammonia

C. Carbon dioxide

D. All the above
4950. In sewers designed with self cleansing velocity________________?
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A. The bottom is silted

B. The bottom is scoured

C. Both silting and scouring occur at the bottom

D. Neither silting nor scouring occurs at the bottom
4951. The recommended detention period for grit chambers is_______________?
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A. 1 minute

B. 3 minutes

C. 5 minutes

D. 2 minutes

4952. The sewer which collects the discharge from a collecting system and delivers it to a treatment plant, is known_____________________?
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A. Branch sewer

B. Sewer outfall

C. House sewer

D. Lateral sewer

4953. If the diameter of a sewer is 100 mm, the gradient required for generating self cleansing velocity is__________________?
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A. None of these

B. 1 in 120

C. 1 in 60

D. 1 in 100

4954. In a trickling filter_________________?
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A. Filtration process is used

B. Biological action is used

C. Neither A. nor B.

D. Both A. and B.

4955. The gradient of sewers depends upon_________________?
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A. All the above

B. Discharge

C. Velocity of flow

D. Diameter of the sewer

4956. In a fully mechanised composting plant, involves________________?
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A. Mechanized receipt

B. All of these

C. Mechanized segregation

D. Mechanized pulverising of refuse

4957. The clarigesters are_________________?
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A. Circular Imhoff double tanks with bottom hoppers

B. Circular septic tanks

C. Circular Imhoff double storey tanks without bottom hoppers

D. Rectangular septic tanks

4958. If is the diameter of upper circular portion, the overall depth of New Egg shaped sewer section, Is_____________________?
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A. 1.425 D

B. 1.625 D

C. 1.250 D

D. 1.350 D

4959. Pick up the correct statement from the following ?
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A. Medium sewers are cleaned by cane rodding

B. Small sewers are cleaned by flushing

C. All the above

D. Medium sewers may be cleaned by pills

4960. Pick up the correct statement from the following?
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A. The period after which the entire area starts contributing to the runoff, is called the time of concentration

B. All the above

C. The maximum rate of storm runoff is called peak drainage discharge

D. Rational method of estimating peak run off, may be used precisely for areas less than 50 hectares