Waste Water Engineering
Question No. 01
For a continuous flow type of sedimentation tanks
(A)
Width of the tank is normally kept about 6 m
(B)
Length of the tank is normally kept 4 to 5 times the width
(C)
Maximum horizontal flow velocity is limited to 0.3 m/minute
(D)
All the above
Answer:
Option D
Question No. 02
The asbestos cement sewers are
(A)
Light in weight
(B)
Not structurally strong to bear large compressive stress
(C)
Susceptible to corrosion by sulphuric acid
(D)
All the above
Answer:
Option D
Question No. 03
For efficient working of a sewer, it must be ensured that
(A)
Minimum velocity of 0.45 m/sec, is maintained at its minimum flow
(B)
A maximum velocity of 0.90 m/sec, is maintained at its maximum flow
(C)
Both (a) and (b)
(D)
Neither (a) nor (b)
Answer:
Option C
Question No. 04
Pick up the correct statement from the following:
(A)
The sewer pipes of sizes less than 0.4 m diameter are designed as running full
at maximum
discharge
(B)
The sewer pipes of sizes greater than 0.4 m diameter are designed as running
2/3rd or 3/4th
full
at maximum discharge
(C)
The minimum design velocity of sewer pipes is taken as 0.8 m/sec
(D)
All the above
Answer:
Option D
Question No. 05
Pick up the correct statement from the following:
(A)
Maximum daily flow = 2 times the average daily flow
(B)
Maximum daily flow = ⅔ × average daily flow
(C)
Sewers are designed for minimum permissible velocity at minimum flow
(D)
All the above
Answer:
Option D
Question No. 06
Bottom openings 15 cm × 15 cm in the standing baffle wall are
provided
(A)
15 cm c/c
(B)
22.5 cm c/c
(C)
30 cm c/c
(D)
50 cm c/c
Answer:
Option B
Question No. 07
The pressure exerted by
(A)
The sewage when running full from inside, is called internal pressure
(B)
The internal pressure if any, causes tensile stress in the pipe material
(C)
Pressure sewers are designed to be safe in tension
(D)
All the above
Answer:
Option D
Question No. 08
For drainage pipes in buildings the test applied before putting
them to use, is
(A)
Water test
(B)
Smoke test
(C)
Straightness test
(D)
All the above
Answer:
Option B
Question No. 09
No treatment of the sewage is given if dilution factor is
(A)
Less than 150
(B)
Between 150 to 200
(C)
Between 200 to 300
(D)
More than 500
Answer:
Option D
Question No. 10
Which of the following pumps in used to pump sewage solids with
liquid sewage without clogging
the pump is?
(A)
Centrifugal pump
(B)
Pneumatic ejector
(C)
Reciprocating pump
(D)
None of these
Answer:
Option A
Question No. 11
Acid regression stage of sludge digestion at a temperature 21°C
extends over a period of
(A)
15 days
(B)
30 days
(C)
60 days
(D)
90 days
Answer:
Option D
Question No. 12
Pick up the correct statement from the following:
(A)
Small sewers are cleaned by flushing
(B)
Medium sewers are cleaned by cane rodding
(C)
Medium sewers may be cleaned by pills
(D)
All the above
Answer:
Option D
Question No. 13
The coagulant which is generally not used for treating the sewage,
is
(A)
Alum
(B)
Ferric chloride
(C)
Ferric sulphate
(D)
Chlorinated copperas
Answer:
Option A
Question No. 14
The layers of vegetable wastes and night soil alternatively piled
above the ground to form a
mound, is called
(A)
A heap
(B)
Plateau
(C)
Windrow
(D)
None of these
Answer:
Option D
Question No. 15
If the flame of a miner's safety lamp in the upper layers of the
sewer forms an explosive, the
sewer certainly contains
(A)
Hydrogen sulphide
(B)
Carbon dioxide
(C)
Methane
(D)
Oxygen
Answer:
Option C
Question No. 16
The gas which may cause explosion in sewers, is
(A)
Carbondioxide
(B)
Methane
(C)
Ammonia
(D)
Carbon monoxide
Answer:
Option B
Question No. 17
Pick up the correct statement from the following:
(A)
The water supply pipes carry pure water free from solid particles
(B)
The water supply pipes get clogged if flow velocity is less than self cleansing
velocity
(C)
The sewers may be carried up and down the hills and valleys
(D)
The sewer pipes are generally laid along level hills
Answer:
Option A
Question No. 18
Pick up the incorrect statement from the following:
(A)
The process of decomposing the organic matter under controlled anaerobic
conditions, is
called
sludge digestion
(B)
Sludge digestion is carried out in sludge tank
(C)
The gases produced in sludge digestion process, contain 75% carbon dioxide
(D)
The gases produced in sludge digestion process, contain 75% methane
Answer:
Option C
Question No. 19
The sewer pipes
(A)
Carry sewage as gravity conduits
(B)
Are designed for generating self-cleansing velocities at different discharge
(C)
Should resist the wear and tear caused due to abrasion
(D)
All the above
Answer:
Option D
Question No. 20
The settling velocity of the particles larger than 0.06 mm in a
settling tank of depth 2.4 is 0.33 m
per sec. The detention period recommended for the tank, is
(A)
30 minutes
(B)
1 hour
(C)
1 hour and 30 minutes
(D)
2 hours
Answer:
Option D
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