Q.1
As compared to cast iron pipes, steel pipes are
  • Heavier
  • Stronger
  • Costlier
  • Less susceptible to corrosion
Q.2
Sewage treatment units are designed for
  • Maximum flow only
  • Minimum flow only
  • Average flow only
  • Maximum and minimum flow
Q.3
Facultative bacteria are able to work in
  • Presence of oxygen only
  • Absence of oxygen only
  • Presence as well as in absence of oxygen
  • Presence of water
Q.4
An egg shaped section of sewer
  • Is economical than circular section
  • Provides self cleansing velocity at low discharges
  • Is more stable than circular section
  • Is easy to construct
Q.5
The length of rectangular sedimentation tank should not be more than(Where ‘B’ is the width of the tank)
  • B
  • 2B
  • 4B
  • 8B
Q.6
The self cleansing velocity for all sewers in India is usually
  • Less than 1.0 m/sec
  • 1.0 m/sec to 1.2 m/sec
  • 1.5 m/sec to 2.0 m/sec
  • 3.0 m/sec to 3.5 m/sec
Q.7
In water treatment, rapid gravity filters are adopted to remove
  • Dissolved organic substances
  • Dissolved solids and dissolved gases
  • Floating solids and dissolved inorganic solids
  • Bacteria and colloidal solids
Q.8
Most suitable section of sewer in separate sewage system is
  • Rectangular section
  • Circular section
  • Standard form of egg shaped sewer
  • Modified egg shaped section
Q.9
The most common cause of acidity in water is
  • Carbon dioxide
  • Oxygen
  • Hydrogen
  • Nitrogen
Q.10
Period of cleaning of slow sand filters is about
  • 24 - 48 hours
  • 10 - 12 days
  • 2 - 3 months
  • 1 - 2 year
Q.11
Residual chlorine in water is determined by
  • Starch iodide method
  • Orthotolidine method
  • Both (A) and (B)
  • None of the above
Q.12
The means of access for inspection and cleaning of sewer line is known as
  • Inlet
  • Manhole
  • Drop manhole
  • Catch basin
Q.13
The maximum efficiency of BOD removal is achieved in
  • Oxidation pond
  • Oxidation ditch
  • Aerated lagoons
  • Trickling filters
Q.14
A sewer that receives the discharge of a number of house sewers is called
  • House sewer
  • Lateral sewer
  • Intercepting sewer
  • Sub-main sewer
Q.15
As compared to geometrical increase method of forecasting population, arithmetical increase method gives
  • Lesser value
  • Higher value
  • Same value
  • Accurate value
Q.16
Double filtration is used
  • To increase the filtration slow sand filters capacity of
  • To increase the filtration rapid sand filters capacity of
  • For isolated buildings like pools, hotels etc swimming
  • All of the above
Q.17
Septic tank is a (i) Settling tank (ii) Digestion tank (iii) Aeration tank
  • Only (i)
  • (i) and (ii)
  • (i) and (iii)
  • Only (iii)
Q.18
For normal sludge, the value of sludge index for Indian conditions is
  • 0 to 50
  • 50 to 150
  • 150 to 350
  • 350 to 500
Q.19
The percentage of filtered water, which is used for backwashing in rapid sand filters, is about
  • 0.2 to 0.4
  • 0.4 to 1.0
  • 2 to 4
  • 5 to 7
Q.20
The percentage of chlorine in fresh bleaching powder is about
  • 10 to 15
  • 20 to 25
  • 30 to 35
  • 40 to 50
Q.21
For a country like India, where rainfall is mainly confined to one season, the suitable sewerage system will be
  • Separate system
  • Combined system
  • Partially combined system
  • Partially separate system
Q.22
Dissolved oxygen in streams is
  • Maximum at noon
  • Minimum at noon
  • Maximum at midnight
  • Same throughout the day
Q.23
If the time of concentration is 9 minutes, then the intensity of rainfall according to British Ministry of Health formula will be
  • 4 mm/hr
  • 10 mm/hr
  • 20 mm/hr
  • 40 mm/hr
Q.24
A pipe which is installed in the house drainage to preserve the water seal of traps is called
  • Vent pipe
  • Anti-siphonage pipe
  • Waste pipe
  • Soil pipe
Q.25
The rate of Alteration of pressure filters is
  • Less than that of slow sand filters
  • In between the filtration rate of slow sand filters and rapid sand filters
  • Greater than that of rapid sand filters
  • Equal to that of slow sand filters
Q.26
Select the correct relationship between porosity (N), specific yield (y) and specific retention (R)
  • N = y + R
  • y = N + R
  • R = N + y
  • R > (N + y)
Q.27
The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is
  • Reflux valve
  • Sluice valve
  • Air relief valve
  • Pressure relief valve
Q.28
Which of the following is not a water borne disease?
  • Dysentery
  • Cholera
  • Typhoid
  • Malaria
Q.29
The rate of BOD exerted at any time is
  • Directly proportional to BOD satisfied
  • Directly proportional to BOD remaining
  • Inversely proportional to BOD satisfied
  • Inversely proportional to BOD remaining
Q.30
If the coli form bacteria is present in a sample of water, then the coli-form test to be conducted is (i) Presumptive coli-form test (ii) Confirmed coli-form test (iii) Completed coli-form test
  • Only (i)
  • Both (i) and (ii)
  • Both (i) and (iii)
  • All (i), (ii) and (iii)
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