Environmental Engineering Multiple Choice Questions on “Pressure Filter”.
1. In which of the following filter, water is passed under higher pressure?
a) Slow sand filter
b) Rapid sand filter
c) Dual media filter
d) Pressure filter
Answer: d
Clarification: The pressure filter is a type of rapid sand filter kept in a closed container where water is passed under higher pressure.
2. What is the range of pressure in pressure filter?
a) 1-5 kg/cm2
b) 2-5 kg/cm2
c) 3-7 kg/cm2
d) 1-8 kg/cm2
Answer: c
Clarification: The range of pressure of pressure filter is 3-7 kg/cm2, which is done by pumping either in horizontal or vertical type pressure filter.
3. The diameter of the vertical type pressure filter is __________
a) 2-2.5 m
b) 1 m
c) 5 m
d) 10m
Answer: a
Clarification: The diameter of the vertical type pressure filter is 2-2.5 m and its length varies from 2.5 to 8m.
4. Filtration operation in pressure filter is same as in rapid sand filter.
a) True
b) False
Answer: b
Clarification: In pressure filter, the coagulated water is applied to filter directly without any mixing or flocculation process, whereas in rapid sand filter, the flocculation takes place after coagulation and then it is applied to the filtration process.
5. The effective size of a pressure sand filter is ______
a) 0.45mm
b) 0.7mm
c) 0.8mm
d) 0.9mm
Answer: a
Clarification: The effective size of a pressure sand filter lies in the range of 0.35-0.6mm and its common value is 0.45mm.
6. What is the value of uniformity coefficient in a pressure sand filter?
a) 1
b) 1.5
c) 2
d) 2.5
Answer: b
Clarification: The value of uniformity coefficient in a pressure sand filter lies between 1.2 and 1.7 and its common value is 1.5.
7. The thickness of sand bed of a pressure filter is _____ cm.
a) 10-20
b) 20-30
c) 30-50
d) 50-60
Answer: d
Clarification: The thickness of sand bed of a pressure filter is 50-60 cm, whereas the gravel layers of pressure filter are same as a rapid sand filter.
8. Which type of filter is used in treating swimming pool water?
a) Slow sand filter
b) Rapid sand filter
c) Dual media filter
d) Pressure filter
Answer: d
Clarification: The pressure filter is used for treating swimming pool water. It is also used for clarifying softened water at industrial plants.
9. The under drainage system in pressure consists of __________
a) Central drains connected to lateral drain
b) Wheeler system
c) Wagner system
d) Pipe grids, false bottom
Answer: d
Clarification: The under drainage system in pressure consists of pipe grids, false bottom and the washing of filter media is accomplished by reversing the flow by manipulating the valves in the pipe.
10. Consider the following statements regarding pressure filter.
i. It is easy to inspect the under drainage system
ii. It is not possible to provide time for chlorination in direct supply from it
iii. It is not possible to observe the degree of back washing and the agitation process
Which of the above statement is correct?
a) i only
b) ii, iii
c) i, ii, iii
d) i, iii
Answer: b
Clarification: It is difficult to inspect, replace and clean the sand, gravel and under drainage system of pressure filter.
11. The rate of filtration of pressure filtration is ______ l/m2/hour.
a) 1000-5000
b) 5000-10000
c) 6000-8000
d) 6000-15000
Answer: d
Clarification: The rate of filtration of pressure filtration is 6000-15000l/m2/hour due to which it is used for treatment of swimming pool water.