Water And Wastewater Engineering Set 6 MCQs

Q1 | The asbestos cement pipes are generally laid

Horizontally

Vertically

At an angle of 30°

At an angle of 60°

Q2 | The design period in years for pumping plants, is

) 1

2 to 3

3 to 5

5 to 10

Q3 | Design period of 40 to 50 years is adopted for

Branch sewers

Main sewers

Trunk sewers

All the above

Q4 | In very first stage of decomposition of the organic matter in sewage

Nitrites are formed

Nitrates are formed

Carbondioxide is formed

Ammonia is formed

Q5 | In a city the ratio of the drainage to sewage is 20, the percentage discharge passing throughnonmonsoon periods, is

5

10

15

20

Q6 | The self-cleansing velocity of water flowing through pipe lines, is

2 metres/sec

1 metre/sec

0.5 metre/sec

0.25 metre/sec

Q7 | In case of sewer lines

Water test is carried out to check water tightness of the joints

Test for straightness is carried out with the help of a lamp and mirror

Obstruction test is carried out with the help of smooth ball of diameter 13 mm

All the above

Q8 | The normal values of over flow rates for secondary sedimentation tanks, ranges between

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

40,000 to 50,000 litres/sqm/day

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

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

Q9 | A manhole is classified as shallow if its depth is between

0.4 to 0.5 m

0.5 to 0.7 m

0.7 to 0.9 m

0.9 to 1.20 m

Q10 | The first stage of neutral process of sludge digestion, is

Acid fermentation

Acid regression

Alkaline fermentation

None of these

Q11 | The formula V = (1/n) r2/3 ?? used for determining flow velocities in sewers is known as,

Chezy's formula

Bazin's formula

Kutter's formula

Manning's formula

Q12 | In sewers the highest non-scouring velocity is achieved in

Glazed bricks sewers

Cast iron sewers

Cement concrete sewers

Stone ware sewers

Q13 | When the reduced level of the water source is higher than the reduced level of the consumer'splace, water is generally supplied

By pumping system

By gravitational system

Both (a) and (b)

All the above

Q14 | Surcharge storage zone of a reservoir, is

Below dead storage (B) (C) (D)

Between dead storage and useful storage

Above useful storage

Also known as valley storage

Q15 | In pressure supply mains, water hammer pressure is reduced by providing

Sluice valves

Air valves

Pressure relief valves

None of these

Q16 | Specific capacity or yield of wells, is generally expressed, as

m 3 per sec

m 3 /hour

m 3 /hour/m2

m 3 /hour/m2 /m

Q17 | Turbidity of raw water is a measure of

Suspended solids

Acidity of water

B.O.D.

None of these

Q18 | If the chosen diameter of a pipe, is less than the economical diameter

Cost of pipe will be less

Head loss will be high

Cost of pumping will be more than saving

All the above

Q19 | While determining the yield of open wells by the pumping test

Velocity of recharging water, increases with depression head

Depression head resulting at critical velocity, is called critical depression head

Working head is generally limited to 1/3 rd of the critical depression head

Maximum safe yield of an open well, is expected at critical depression head

Q20 | The process of passing water through beds of granular materials, is called

Screening

Sedimentation

Filtration

None of these

Q21 | For the prediction of future population of a city, the factor to be considered, is

Births

Deaths

Migrants

All the above

Q22 | Mathamoglobinemia or blue baby disease is caused due to

Chlorides

Nitrites

Nitrates

Sulphides

Q23 | To control the growth of algae in reservoirs, the compound which is used, is

Bleaching powder

Copper sulphate

Lime solution

Alum solution

Q24 | A pressure conduit laid underground, may not be subjected to

Internal pressure of water

Pressure due to external load

Longitudinal temperature stress

Longitudinal stresses due to unbalanced pressure to bends

Q25 | The bacterias which require free oxygen for their survival, are called

Aerobic bacterias

Anaerobic bacterias

Facultative bacteria

None of these