Waste Water Engineering Multiple Choice Questions on “Disc Filtration – 1”.
1. Disc filter is similar to a screen filter.
a) True
b) False
Answer: a
Clarification: A disc filter is a type of water filter used primarily in irrigation, similar to a screen filter, except that the filter cartridge is made of a number of plastic discs stacked on top of each other like a pile of poker chips.
2. Filtration is based on colour of particles.
a) True
b) False
Answer: b
Clarification: The filtration quality is based on the quantity and size of particles that the filtering element is able to retain. Higher quality filtration simply means cleaner water. This depends on the geometry of the channels, including the size, length, angle and number of generated intersection points.
3. Which of the following parameter is used by disc filters?
a) Size
b) Colour
c) Taste
d) Smell
Answer: a
Clarification: Higher quality filtration simply means cleaner water. This depends on the geometry of the channels, including the size, length, angle and number of generated intersection points.
4. Discs are colour coded to denote _______
a) Water level
b) Wastewater level
c) Velocity
d) Level of filtration
Answer: d
Clarification: The discs are typically colour coded to denote the level of filtration. Filtration quality is usually measured in microns, based on the smallest size particle filtered. The typical range is from 25 microns for the finest level of filtration to 400 microns for the coarsest.
5. What is the common unit used to measure filtration quality?
a) Litre
b) Cumic
c) Microns
d) Galloon
Answer: c
Clarification: Filtration quality is usually measured in microns, based on the smallest size particle filtered. The typical range is from 25 microns for the finest level of filtration to 400 microns for the coarsest.
6. What is the value for the finest level of filtration?
a) 5 microns
b) 15 microns
c) 20 microns
d) 25 microns
Answer: d
Clarification: The typical range is from 25 microns for the finest level of filtration to 400 microns for the coarsest. The filtration quality is given as the equivalent mesh size of a comparable screen filter.
7. What is the value for coarse filtration?
a) 100 microns
b) 200 microns
c) 300 microns
d) 400 microns
Answer: d
Clarification: Sometimes the filtration quality is given as the equivalent mesh size of a comparable screen filter. When using mesh sizes, 40 is the coarsest and 600 is the finest or highest level of filtration.
8. What is the smallest mesh size of the filter is used?
a) 250
b) 400
c) 550
d) 600
Answer: d
Clarification: Mesh sizes usually range from 40 to 600. When using mesh sizes, 40 is the coarsest and 600 is the finest or highest level of filtration.
9. What is the maximum mesh size being used?
a) 20
b) 40
c) 45
d) 55
Answer: b
Clarification: When using mesh sizes, 40 is the coarsest and 600 is the finest or highest level of filtration. The filtration quality is given as the equivalent mesh size of a comparable screen filter.
10. In which year was the disc filter developed?
a) 1922
b) 1930
c) 1932
d) 1936
Answer: d
Clarification: In 1936 disc filter was originally developed to filter hydraulic fluid in the B-17 bomber. In these filters, the discs were made of stainless steel and brass. This type of filter began to be used in Israel to filter irrigation water in the 1960s.
11. Which of the following is an advantage of disc filter?
a) Flush water
b) Area
c) Speed
d) Cost
Answer: a
Clarification: In 1936 disc filter was originally developed to filter hydraulic fluid in the B-17 bomber. In these filters, the discs were made of stainless steel and brass. This type of filter was used in Israel in the 1960s to filter irrigation water.