civil engineering MCQs – Page 220

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 Review each marked answer and report any item that may be outdated or unclear.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
4381. 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

4382. 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
4383. 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
4384. 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

4385. 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

4386. 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

4387. The main disadvantage of cement concrete sewers is________________?
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A. difficulty in transportation due to heavy weight

B. difficulty in construction

C. less strength

D. less life

4388. Orthotolidine test is used for determination of________________?
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A. residual chlorine

B. dissolved oxygen

C. biochemical oxygen demand

D. dose of coagulant

4389. The process of lagooning is primarily a means of________________?
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A. increasing the capacity of storage re-servoirs

B. reducing the excessive flow in sewers

C. increasing flow of sewage through imhoff tanks

D. disposing of sludge
4390. Sewage treatment units are designed for_______________?
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A. average flow only

B. maximum and minimum flow

C. maximum flow only

D. minimum flow only

4391. The type of valve, which is provided on the suction pipe in a tube-well, is____________?
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A. air relief valve

B. pressure relief valve

C. reflux valve

D. sluice valve

4392. The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by_______________?
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A. TOD>COD>BOD

B. TOD>BOD>COD

C. COD>BOD>TOD

D. BOD>COD>TOD

4393. Double filtration is used_______________?
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A. to increase the filtration slow sand filters capacity of

B. for isolated buildings like pools, hotels etc swimming

C. all of the above

D. to increase the filtration rapid sand filters capacity of

4394. The overflow rate for plain sedimentation tanks is about__________________?
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A. 500 to 750 litres/hour/ m2

B. 1500 to 2000 litres/hour/m2

C. 1000 to 1250 litres/hour/ m2

D. 1250 to 1500 litres/hour/m2

4395. The chemical most commonly used to increase speed of sedimentation of sewage is_______________?
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A. sodium permanganate

B. copper sulphate

C. sulphuric acid

D. lime
4396. Composting and lagooning are the methods of_______________?
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A. sedimentation

B. sludge disposal

C. sludge digestion

D. filtration

4397. The characteristics of fresh and septic sewage respectively are____________________?
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A. acidic and alkaline

B. alkaline and acidic

C. both acidic

D. both alkaline

4398. Standard BOD is measured at________________?
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A. 20C 5day

B. 25C- 3day

C. 20C 1day

D. 30C- 5day

4399. The time of concentration is defined as_______________?
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A. sum of (A) and (B)

B. the time taken by rainfall water to run from most distant point of water shed to the inlet of sewer

C. the time required for flow of water in sewer to the point under consideration

D. difference of (A) and (B)

4400. Sewerage system is usually designed for_________________?
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A. 10 years

B. 25 years

C. 75 years

D. 50 years