Civil Engineering Drawing Mcqs

Q:

The per capita sewage generation can be considered as 35 to 50% of the per capita water supplied per day.

A) True B) False
 
Answer & Explanation Answer: B) False

Explanation: The per capita sewage generation can be considered as 75 to 80% of the per capita water supplied per day. The increase in population also result in increase in per capita water demand and hence, per capita production of sewage. This increase in water demand occurs due to increase in living standards, betterment in economic condition, changes in habit of people, and enhanced demand for public utilities.

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21
Q:

Fluctuation in flow occurs from hour to hour and from season to season.

A) True B) False
 
Answer & Explanation Answer: A) True

Explanation: Variation occurs in the flow of sewage over annual average daily flow. Fluctuation in flow occurs from hour to hour and from season to season. If the flow is gauged near its origin, the peak flow will be quite pronounced. The peak will defer if the sewage has to travel long distance. This is because of the time required in collecting sufficient quantity of sewage required to fill the sewers and time required in travelling.

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18
Q:

Disinfection of drinking water is done to remove odour.

A) True B) False
 
Answer & Explanation Answer: B) False

Explanation: Water disinfection means the removal, deactivation or killing of pathogenic microorganisms. Microorganisms are destroyed or deactivated, resulting in termination of growth and reproduction. When microorganisms are not removed from drinking water, drinking water usage will cause people to fall ill.

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21
Q:

What is the diameter of a domestic sewer pipe laid at gradient 1 in 100?

A) 150 mm B) 250 mm
C) 120 mm D) 80 mm
 
Answer & Explanation Answer: A) 150 mm

Explanation: Following are some recommendations for domestic sewer pipe.
100 mm – 1 in 60.
150 mm – 1 in 100.
200 mm – 1 in 120.

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20
Q:

What is the detention period in a septic tank?

A) 24 hours B) 12 hours
C) 06 hours D) 36 hours
 
Answer & Explanation Answer: A) 24 hours

Explanation: Detention period of 24hrs (mostly) considered in septic tank design. The rate of flow of effluent must be equal to the rate of flow of influent.

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21
Q:

Cost of fittings and their fixing is specified for the following sanitary fittings.

A) Water closets B) Flushing pipes
C) Lavatory basins D) Water closets, Flushing pipes and lavatory basins
 
Answer & Explanation Answer: D) Water closets, Flushing pipes and lavatory basins

Explanation: A fitting is used in pipe systems to connect straight pipe or tubing sections, adapt to different sizes or shapes and for other purposes, such as regulating (or measuring) fluid flow. “Plumbing” is generally used to describe the conveyance of water, gas, or liquid waste in domestic or commercial environments; “piping” is often used to describe the high-performance (high-pressure, high-flow, high-temperature or hazardous-material) conveyance of fluids in specialized applications. “Tubing” is sometimes used for lighter-weight piping, especially that flexible enough to be supplied in coiled form.
Fittings (especially uncommon types) require money, time, materials and tools to install, and are an important part of piping and plumbing systems. Valves are technically fittings but are usually discussed separately.

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21
Q:

Pick up the correct statement in case of water supply.

A) Pipes laid in trenches and pipes fixed to walls are measured separately B) Cutting through walls and floors are included with the item
C) Pipes are classified according to their sizes and quality D) Pipes laid in trenches, cutting through walls and pipes classified as per size
 
Answer & Explanation Answer: D) Pipes laid in trenches, cutting through walls and pipes classified as per size

Explanation: The product, delivered to the point of consumption, is called potable water if it meets the water quality standards required for human consumption.
The water in the supply network is maintained at positive pressure to ensure that water reaches all parts of the network, that a sufficient flow is available at every take-off point and to ensure that untreated water in the ground cannot enter the network. The water is typically pressurised by pumps that pump water into storage tanks constructed at the highest local point in the network. One network may have several such service reservoirs.
In small domestic systems, the water may be pressurised by a pressure vessel or even by an underground cistern (the latter however does need additional pressurizing). This eliminates the need of a water-tower or any other heightened water reserve to supply the water pressure.

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30
Q:

A city has a projected population of 60,000 spread over area of 50 hectare. Find the design discharge for the separate sewer line by assuming rate of water supply of 250 LPCD and out of this total supply only 75 % reaches in sewer as wastewater. Make necessary assumption whenever necessary.

A) 0.26 m³/s B) 0.6 m³/s
C) 0.76 m³/s D) 3.26 m³/s
 
Answer & Explanation Answer: A) 0.26 m³/s

Explanation: Given data, Q = 250 lit/capita/day
Sewage flow = 75% of water supply = 0.75* 250 = 187.5 LPCD
Total sewage generated = 187.5*60000/(24*3600) = 130.21 lit/sec = 0.13 m³/s
Assume peak factor = 2
Total design discharge = 0.26 m³/s.

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