The design period of sewage treatment works in normally:
Options are :
- 5 - 10 years
- 15 - 20 years
- 40 - 50 years
- 30 - 40 years
Answer :15 - 20 years
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 10
Pick up the correct statement from the following:
Options are :
- The circular sewers work efficiently if the sections run at least half full
- The circular sewers are provided for separate sewerage system
- The circular section of sewers provides maximum hydraulic mean depth
- Two sewers of different shapes are said to be hydraulically equivalent if they discharge at the same rate while running full on the same grade
- All the above
Answer :All the above
Pick up the correct statement from the following:
Options are :
- The automatic purification of polluted water, is known self purification phenomenon
- Grab sample is generally obtained from the surface where turbulence mixes the sewage particles
- The photosynthesis is carried out in the presence of sun light
- The ratio of the quantity of the diluting water to that of the sewage, is known as dilution factor
- All the above
Answer :All the above
Kjedahl nitrogen is a mixture of:
Options are :
- Nitrogen and organic nitrogen
- All the above
- Organic nitrogen and ammonia
- Ammonia and nitrogen
Answer :All the above
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 11
The sewer which received discharge from two or more main sewers, is known as:
Options are :
- A trunk sewer
- An outfall sewer
- A main sewer
- An intercepting sewer
Answer :A trunk sewer
Pick up the correct statement from the following:
Options are :
- Inlets having vertical openings, are called curb inlets
- Inlets having horizontal openings, are called horizontal inlets
- Inlets are generally provided at an interval of 30 m to 60 m along straight roads
- Inlets are provided on the road surface at the lowest point for draining rain water
- All the above
Answer :All the above
If D is the diameter of upper circular portion, the area of cross-section of a standard egg shaped sewer, is:
A.
B.
C.
D.
Options are :
Answer :A
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 2
If a paper moistened with lead acetate for five minutes when placed in manhole turns black. The sewer certainly contains:
Options are :
- Carbon dioxide
- Hydrogen sulphide
- Methane
- None of these
- Oxygen
Answer :Hydrogen sulphide
For design of sewers, percentage of sewage discharge is assumed:
Options are :
- 75 to 80%
- 70 to 75%
- 85%
- 65 to 70%
Answer :75 to 80%
The porosity of sediments in sewer pipes, is usually taken as:
Options are :
- 0.010
- 0.012
- 0.011
- 0.020
- 0.013
Answer :0.013
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 3
The
sewage discharge in a detritus tank of a treatment plant is 576
litres/sec with flow velocity of 0.2 m/sec. If the ratio of width to
depth is 2, the depth is:
Options are :
- 110 cm
- 100 cm
- 120 cm
- 150 cm
Answer :120 cm
In case of sewer lines:
Options are :
- Water test is carried out to check water tightness of the joints
- Obstruction test is carried out with the. help of smooth ball of diameter 13 mm
- All the above
- Test for straightness is carried out with the help of a lamp and mirror
Answer :All the above
The arrangement made for passing the sewer line below an obstruction below the hydraulic gradient lines called:
Options are :
- Sag pipe
- Inverted syphon
- All of these
- Depressed sewer
Answer :All of these
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 4
If D is the diameter of upper circular portion, the overall depth of New Egg shaped sewer section, is:
Options are :
- 1.625 D
- 1.350 D
- 1.250 D
- 1.425 D
Answer :1.625 D
The sewerage system originates from:
Options are :
- House sewers
- Branch sewers
- Out fall sewers
- Main sewers
- Lateral sewers
Answer :House sewers
For estimating the peak run off the rational formula Q = 0.0278 KpA was evolved by:
Options are :
- Lloyd Davis
- All the above
- Frubling
- Kinchling
Answer :All the above
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 5
In sewage, the solids in mg per litre is:
Options are :
- 1500 to 2000
- 1000 to 1500
- 500 to 1000
- 100 to 500
Answer :500 to 1000
In sewers the velocity of flow should not be:
Options are :
- Less than the self-cleansing velocity
- More than the self-cleansing velocity
- Less than 10 m/sec
- More than 20 m/sec
Answer :Less than the self-cleansing velocity
Large diameter sewers subjected to external pressure alone, are reinforced:
Options are :
- None of these
- Near the outer surface of the pipe
- Near the inner surface of the pipe
- Both A and B
- With elliptical cage
Answer :With elliptical cage
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 6
The
reduced levels of the string at the consecutive sight rails A and B are
203.575 m, 203.475 m respectively. If the difference of their R.D.s is
10 m, the gradient of the sewer line is:
Options are :
- 1 in 500 upward
- 1 in 100 downward
- 1 in 503 upward
- 1 in 100 upward
Answer :1 in 100 downward
Assertion (A) : A free board of 0.3 m is provided above the top sewage line in septic tanks
Reason (R) : It helps to accommodate the scum in the septic tank
Options are :
- Both A and R are true but R is not a correct explanation of A
- A is true but R is false
- A is false but R is true
- Both A and R are true and R is the correct explanation of A
Answer :Both A and R are true and R is the correct explanation of A
A safety lamp when inserted in the upper portion of a manhole causes flames. It indicates the presence of:
Options are :
- Carbondioxide gas
- Hydrogen sulphide gas
- Methane gas
- Petrol vapours
Answer :Methane gas
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 7
The sewer which transports the sewage to the point of treatment, is called:
Options are :
- Branch sewer
- House sewer
- Out-fall sewer
- Lateral
- Main sewer
Answer :Out-fall sewer
The detention time (t) of a settling tank, may be defined as the time required for:
Options are :
- None of these
- The flow of sewage to fill the tank
- A particle to travel from top surface to bottom sludge zone
- A particle to travel along its length
Answer :The flow of sewage to fill the tank
The ratio of depths at partial flow with central angle ? and at full flow of a sewer, is:
A.
B.
C.
D.
E.
Options are :
Answer :C
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 8
Pick up the correct statement from the following:
Options are :
- Manhole covers are made circular for the convenience of the cleaning staff
- All the above
- A manhole is classified as deep manhole if its depth is more than 1.5 m
- The boning rod is used for checking the levels of the sewer inverts
- A manhole is classified as shallow manhole if its depth is. less than 0.9 m
Answer :All the above
A circular sewer section is preferred to because:
Options are :
- It is cheaper in construction
- It provides maximum hydraulic mean depth
- It provides maximum area for a given perimeter
- All the above
Answer :All the above
The maximum depth of sedimentation tanks, is kept:
Options are :
Answer :3 m
Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 9
You are asked to design sewer pipes of diameters 0.4 m to 0.9 m at maximum flow, you will assume the sewer flow running at:
Options are :
- Full depth
- Three fourth full
- Two third full
- Half full
Answer :Half full
For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed:
Options are :
Answer :2.0
