Engineering Questions with Answers - Multiple Choice Questions

Environmental Engineering MCQ – Types of Sewage Filter

1 - Question

The intermittent sand filters have better BOD removal efficiency than trickling filters.
a) True
b) False

View Answer

Answer: b
Explanation: The trickling filters have the best BOD removal efficiency in comparison to the types of filters used in aerobic treatment with a maximum value of 95%




2 - Question

The filter material used in contact bed is ___________
a) Sand
b) Stone ballast
c) Gravel
d) Fine sand

View Answer

Answer: b
Explanation: The filter material used in the contact bed is broken stones called as stone ballast.




3 - Question

Which of the following is called as contact bed?
a) Primary clarifier
b) Secondary clarifier
c) Contact filter
d) High rate digester

View Answer

Answer: c
Explanation: Contact filters are water tight tanks that are used for the aerobic treatment of sewage. They are also called as contact bed.




4 - Question

How many types of trickling filters are used in sewage treatment?
a) 6
b) 5
c) 3
d) 2

View Answer

Answer: d
Explanation: The trickling filters are divided into conventional and high rate trickling filters.




5 - Question

The depth of the filter media of intermittent filter is ___________
a) 45cm
b) 60cm
c) 20cm
d) 25cm

View Answer

Answer: b
Explanation: The minimum depth of filter media of intermittent filter is 60cm. These filters give highly nitrified effluent.




6 - Question

Which of the following filter is used in the anaerobic treatment of sewage?
a) Intermittent sand
b) Trickling filter
c) Contact filter
d) Biological filter

View Answer

Answer: d
Explanation: Biological filter is used in anaerobic treatment, whereas intermittent sand filter, trickling filter and contact filter are used in the aerobic treatment of sewage.




7 - Question

The maximum size of filter media of a percolating filter is ___________
a) 10mm
b) 25mm
c) 60mm
d) 75mm

View Answer

Answer: d
Explanation: The minimum and maximum size of filter media of a percolating filter is 25mm and 75mm respectively.




8 - Question

The recirculation ratio for the low rate trickling filter is ___________
a) 1
b) 2
c) 3
d) 0

View Answer

Answer: d
Explanation: The recirculation system is not provided in the low rate trickling filter. So, when the recirculation is 0, the type of filter used is a low rate trickling filter.

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