Engineering Questions with Answers - Multiple Choice Questions

Environmental Engineering MCQ – Conventional Trickling Filter

1 - Question

The breaking of the biomass from the slime layer in conventional filter is called _____
a) Sloughing
b) Carbonation
c) Biological magnification
d) Weathering

View Answer

Answer: a
Explanation: The breaking of the biomass from the slime layer in conventional filter is called sloughing. It makes the effluent turbid.




2 - Question

 The minimum hydraulic loading of percolating filter is ___________
a) 1 m3/m2/day
b) 2 m3/m2/day
c) 3 m3/m2/day
d) 4 m3/m2/day

View Answer

Answer: a
Explanation: The minimum hydraulic loading of percolating filter is 1m3/m2/day whereas, the maximum hydraulic loading of percolating filter is 4m3/m2/day.




3 - Question

Which of the following is called as a conventional trickling filter?
a) Rapid sand filter
b) Slow sand filter
c) High rate trickling filter
d) Low rate trickling filter

View Answer

Answer: d
Explanation: Low rate trickling filter is called as a conventional trickling filter. It is also called a standard rate and percolating filter.




4 - Question

The BOD after the filtration of sewage from the low rate trickling filter is ___________
a) 40-50%
b) 80-90%
c) 70-80%
d) 90-99%

View Answer

Answer: b
Explanation: The BOD of the effluent obtained after the filtration of sewage from the low rate trickling filter is between 80 to 90% and the effluent obtained is highly nitrified and stabilized.




5 - Question

The efficiency of a percolating filter is given by ___________
a) 100/(1+0.0044 (μ))
b) 100/(1+0.044 (μ) 1/2)
c) 100/(1+0.44 (μ) 1/2)
d) 100/(1+0.0044 (μ) 1/2)

View Answer

Answer: d
Explanation: The efficiency of a percolating filter is given by η = 100/(1+0.0044 (μ)1/2) where, μ is the organic loading in kg per hectare meter per day.




6 - Question

The removal of BOD is independent of the loading conditions in infiltration process.
a) True
b) False

View Answer

Answer: b
Explanation: When the loading conditions are less, the efficiency of the filter will be more and the removal of BOD from the effluent will be more.




7 - Question

The organic loading in low rate trickling filter is 900 kg/hectare-meter/day. What is the efficiency of the filter?
a) 43.1%
b) 88.3%
c) 7.04%
d) 83%

View Answer

Answer: b
Explanation: Efficiency of low rate trickling filter = 100/(1+0.0044 (μ)1/2) = 100/(1+0.0044 (900)1/2) = 100/1.132 = 88.3.




8 - Question

The organic loading in a trickling filter is measured in ___________
a) m3/day
b) gm/m2/day
c) Kg/hectare-meter/day
d) Kg/hectare/day

View Answer

Answer: c
Explanation: The organic loading in a trickling filter is measured in kg / hectare-meter/day where, 1 hectare = 104m3.




9 - Question

The hydrogen sulfide gas formed during the filtration of sewage can be removed by ___________
a) Carbonation
b) Chlorination
c) Addition of lime
d) Titration with potassium dichromate

View Answer

Answer: b
Explanation: The hydrogen sulfide gas is formed when the fixed nozzles are used during the filtration process, so sewage is chlorinated to prevent the formation of H2S gas.




10 - Question

The recirculation factor in a low rate trickling filter is ___________
a) 0
b) 1
c) 10
d) 100

View Answer

Answer: b
Explanation: The recirculation factor F = (1+ R/I) / (1+0.1 (R/I)) 2 = (1+0) /(1+0)2 = 1.

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