Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 6

The minimum recommended diameter of sewers, is:


Options are :

  • 5 cm
  • 15 cm
  • 20 cm
  • 10 cm

Answer :15 cm

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 7

If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is:


Options are :

  • 1065 mm
  • 1075 mm
  • 1045 mm
  • 1095 mm

Answer :1095 mm

Hydraulic mean radius is:


Options are :

  • Cross-sectional area/wetted perimeter
  • Mean radius of sewer
  • Mean of radii in a pipe line of varying cross-sections
  • Difference in heads between two points in circular pipes

Answer :Cross-sectional area/wetted perimeter

Pick up the correct statement from the following:


Options are :

  • The larger the sewer in size, no deposition will take place
  • The larger the sewer in size, more will be velocity
  • The smaller the sewer in size, less will be velocity
  • The larger the sewer in size, deposition will take place

Answer :The larger the sewer in size, deposition will take place

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 8

The gradient of sewers depends upon:


Options are :

  • Diameter of the sewer
  • Discharge
  • Velocity of flow
  • All the above

Answer :All the above

In sewage having fully oxidised organic matter, the nitrogen exists in the form of:


Options are :

  • Aluminoid nitrogen
  • Free ammonia
  • Nitrates
  • Nitrites
  • None of these

Answer :Nitrates

In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is:


Options are :

  • 2.25
  • 2.50
  • 2.75
  • 2.55
  • 2.65

Answer :2.65

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 9

For non-scouring velocity 5 m/sec, the type of sewers generally preferred to, is:


Options are :

  • Cement concrete sewers
  • Glazed bricks sewers
  • Cast iron sewers
  • Stone ware sewers

Answer :Glazed bricks sewers

A sewer running partially full and hurried with back filled, fails in compression due to:


Options are :

  • Superimposed traffic loads
  • Weight of the pipe
  • All the above
  • Weight of the back fill

Answer :All the above

In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept:


Options are :

  • 2.0
  • 10.0
  • 5.0
  • 0.25

Answer :0.25

Which one of the following tests is used for testing sewer pipes:


Options are :

  • Mirror test
  • Ball test
  • All of these
  • Water test

Answer :All of these

In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is:


Options are :

  • 5
  • 10
  • 20
  • 15

Answer :20

In sewers the gas generally found, is:


Options are :

  • Hydrogen sulphide (H2S)
  • Carbon dioxide (CO2)
  • Petrol vapours
  • All the above
  • Methane (CH4)

Answer :All the above

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 1

To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is:


Options are :

  • 0.60 m/sec
  • 0.70 m/sec
  • 1.0 m/sec
  • 0.50 m/sec
  • 0.75 m/sec

Answer :0.75 m/sec

The recommended detention period for grit chambers is:


Options are :

  • 3 minutes
  • 2 minutes
  • 1 minute
  • 5 minutes

Answer :1 minute

In olden days the type of section adopted in trunk and out fall sewers was:


Options are :

  • Horse shoe shaped
  • Egg shaped
  • Parabolic shaped
  • Circular shaped

Answer :Horse shoe shaped

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 10

In a fully mechanised composting plant, involves:


Options are :

  • Mechanized segregation
  • Mechanized pulverising of refuse
  • Mechanized receipt
  • All of these

Answer :All of these

The gas which may cause explosion in sewers, is:


Options are :

  • Ammonia
  • Carbon monoxide
  • Methane
  • Carbondioxide

Answer :Methane

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:


Options are :

  • 30 minutes
  • 1 hour and 30 minutes
  • 1 hour
  • 3 hours
  • 2 hours

Answer :2 hours

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 11

For providing an type W.C., the R.C.C. slabs in the toilet portion:


Options are :

  • Should be kept 20 cm above the adjacent portion
  • Should be sunk by 20 cm
  • Need not be sunk
  • Should be sunk by 50 cm

Answer :Should be sunk by 50 cm

A rainfall may be classified as acidic if its pH value is less or equal to:


Options are :

  • 6
  • 7
  • 5
  • 6.5

Answer :5

If the depth of partial flow in a sewer of diameter 2 m, is 50 cm, its wetted perimeter is:


A.

?


B.


C.


D.


E.


Options are :

  • C
  • E
  • B
  • D
  • A

Answer :D

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 2

In septic tanks:


Options are :

  • Free board of 0.3 m may be provided
  • The baffles or tees are extended up to top level of scum
  • The inlet is kept 30 cm below the sewage line and outlet is kept at a level 40% depth of the sewage
  • All the above
  • The clear space between the baffle top and covering slab is about 7.5 cm

Answer :All the above

The non-clog pump which permits solid matter to pass out with the liquid sewage, is:


Options are :

  • None of these
  • Reciprocating pump
  • Pneumatic ejector
  • Centrifugal pump

Answer :Centrifugal pump

When drainage to sewage ratio is 20, the peak dry weather flow is:


Options are :

  • Slightly more than 5% of the design discharge
  • Slightly less than 5% of the design discharge
  • None of these
  • 20% of the design discharge

Answer :Slightly less than 5% of the design discharge

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 3

Clogging of sewers, is caused due to:


Options are :

  • Domestic wastes thrown in manholes
  • All the above
  • Greasy and oily matters
  • Low discharge
  • Silting

Answer :All the above

If 2% solution of a sewage sample is incubated for 5 days at 20C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is:


Options are :

  • 250 ppm
  • 225 ppm
  • 200 ppm
  • None of these

Answer :250 ppm

The rate of accumulation of sludge in septic tanks is recommended as:


Options are :

  • 25 litres/person/year
  • 30 litres/person/year
  • 25 litres/person/month
  • 30 litres/person/month

Answer :30 litres/person/year

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 4

The effluent of a septic tank is:


Options are :

  • Foul and contains dissolved and suspended solids
  • As good as that from a complete treatment
  • None of these
  • Fit for discharge into any open drain

Answer :Fit for discharge into any open drain

An inverted siphon is designed generally for:


Options are :

  • Four pipes
  • Two pipes
  • One pipe
  • Three pipes

Answer :Three pipes

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