Environmental Engineering Mid - II, November - 2014

1.The Pipe extending from stop cock upto the storage tank is called
  • Supply pipe
  • Water pipe
  • Waste pipe
  • Communication pipe
Answer: A
2.PVC pipes can withstand pressure head of water upto
  • 50m
  • 75m
  • 100m
  • 125m
Answer: C
3.Rapid sand filter can remove turbidity from water to an extent of
  • 15 to 20 ppm
  • 20 to 25 ppm
  • 25 to 30 ppm
  • 35 to 40 ppm
Answer: D
4.The corrosion in pipe is due to
  • Impurities in the material particularly those having a lower potential
  • Dissolved oxygen in water
  • pH valve of water
  • All of the above
Answer: D
5.Check valves are used
  • To prevent back flow
  • At dead ends
  • At summit points
  • At main and back pipe
Answer: A
6.The rate of accumulation of sludge in septic tanks is recommended as
  • 30 litres/person/year
  • 25 litres/person/year
  • litres/person/month
  • 25 litres/person/month
Answer: A
7.If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is
  • 200 ppm
  • 225 ppm
  • 250 ppm
  • None of the above
Answer: C
8.The most common coagulant is
  • Magnesium sulphate
  • Bleaching powder
  • Alum
  • Chlorine
Answer: C
9.The type of joint provided to release thermal stresses is called
  • Socket and spigot joint
  • Simplex joint
  • Expansion joint
  • Flanged joint
Answer: C
10.Septic tank is
  • An aerobic attached growth treatment system
  • An aerobic suspended growth biological treatment system
  • An anaerobic attached growth biological treatment system
  • An anaerobic suspended growth treatment system
Answer: D
11.Socket and spigot joints are used for _________________.
Answer: C.I pipes
12.Presence of excess fluorine in water causes _____________.
Answer: Fluorosis
13.The bacteria which require oxygen for their survival are known as ______________.
Answer: Aerobic bacteria
14.The valves which are used to remove the sediment in the pipe lines ________________.
Answer: Scour valve
15.____________ process is done to remove turbidity, colour, organic impurities, bacteria, substances causing bad smell.
Answer: Coagulation
16.COD test can be conducted with in_____________ period.
Answer: Three hours
17.The maximum pressure to which cast Iron pipes may be subjected is _______________.
Answer: 7kg/cm2
18.The time for which a water is determined in the settling tank is called _______________.
Answer: Detention time
19.Approach velocity of the waste water in the screening channel shall not fall below a self cleansing velocity of ___________________.
Answer: 37.5 cm/sec
20.Polluted water having low BOD are most economically treated in _________________.
Answer: Oxidation ponds