Sewage Filtration MCQs : This section focuses on the "Sewage Filtration" in Waste Water Engineering. These Multiple Choice Questions (MCQs) should be practiced to improve the Waste Water Engineering skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
How many types of sewage filters there?
Explanation: The sewage filters that are commonly employed are of the following types: 1. Intermittent Sand Filters 2. Contact Beds 3. Trickling Filters 4. Dunbar Filters 5. Magnetite Filters 6. Rapid Sand Filters
The _______________ is the earliest type of sewage filter used in the biological treatment of sewage.
A. contact beds
B. trickling filters
C. intermittent sand filter
D. dunbar filters
Explanation: The intermittent sand filter is the earliest type of sewage filter used in the biological treatment of sewage.
Contact beds also called contact filters.
C. Can be true or false
D. Can not say
Explanation: True, Contact beds also called contact filters
Which of the following are Advantages of Intermittent Sand Filters?
A. Small head is required for applying the sewage on the surface of the filter.
B. There is no secondary sludge which is to be disposed of, except for the occasional sand scraping.
C. The operation is very simple
D. All of the above
Explanation: All of the above are advantage of Intermittent Sand Filters.
How many hours does it take for filters to attain turbidity breakthrough?
A. 12-16 hours
B. 18-22 hours
C. 23-36 hours
D. 38-42 hours
Explanation: The filter operates usually 24-36 hours before attaining turbidity breakthrough. The influent water passes through the filter medium, the supporting layer and the underdrain where it experiences an energy loss due to frictional resistance referred to as head loss.
The rate of filtration of an intermittent sand filter depends mainly ____________ factors.
Explanation: The rate of filtration of an intermittent sand filter depends mainly on the following three factors: Depth and size of filtering material, Nature of the influent and Quality of effluent required
What is the maximum head loss at which the filter should be cleaned?
A. 1.5 m
B. 1.8 m
C. 2 m
D. 2.5 m
Explanation: When the head loss becomes excessive and beyond 1.5-2.5 m, the filter should be cleaned.
What is the specified minimum time for backwash of rapid filters?
A. 2 minutes
B. 5 minutes
C. 10 minutes
D. 15 minutes
Explanation: The entire process of backwashing the filters and restarting the water supply takes about 15 minutes. The specified minimum backwash time for a rapid filter is 5 minutes.
What is the rate of backwash water?
A. 0.3-1 m/min
B. 1-1.5 m/min
C. 0.03-0.3 m/min
D. 15-3 m/min
Explanation: The wash water required for a rapid filter may vary from 3-6% of the total amount of water filtered. Upward wash water rates are usually of the order of 0.3-1.0 m/min.
Trickling filters are also known as percolating filters or sprinkling filters.
C. Can be yes or no
D. Can not say
Explanation: Yes, Trickling filters are also known as percolating filters or sprinkling filters