1. It involves the removal of suspended and colloidal particles from the water by passing it through a layer or bed of porous granular material such as sand. a. Slow Sand Filtration b. Rapid Sand Filtration c. Filtration d. Depth Filtration

2. It is a German term meaning “dirt cover”

a. Schmutzdecke b. Schmutzedecke c. Scmutzdeck d. Schmutzdeck

3. Slow sand filtration was first introduced a. 1600 b. 1700 c.1800 d. 1900

4. A hypogeal biological layer formed on the surface of a slow sand filter

a. Schmutzdecke b. Schmutzedecke c. Scmutzdeck d. Schmutzdeck

5. According to the WHO, "Under suitable circumstances, ______________ may be not only the cheapest and simplest but also the most efficient method of water treatment.” a. Slow sand filtration b. Rapid sand filtration c. Intermittent medium porous filtration d. Recirculating medium porous filtration

6. Slow sand filters are recognized for being superior technology for the treatment of surface water

sources by what organization? a. WHO b. United Nations c. USEPA d. All of the above

7. Cleaning method for a slow sand filter is done through

a. Scraping b. Wet harrowing c. a & b d. None of the above

8. Is the process of removing the top few millimetres of fine sand to expose a new layer of clean sand. a. Slow Sand Filtration b. Wet harrowing c. Scraping d. None of the above

9. Lowering the water level to just above the gelatinous film, stirring the sand and thereby suspending any

solids held in that layer and then running the water to waste. The filter is then filled to full depth and brought back into service. a. Slow Sand Filtration b. Wet harrowing c. Scraping d. None of the above

10. In the formation of biolayer, biofilm on the mineral particles are exactly the same as the observed in

“trickling filters” used for aerobic treatment of wastewater. a. True b. False c. Sometimes d. Never

11. Slow sand filtration is a

a. Physical Process b. Biological Process d. Chemical Process d. None of the above

12. _____________ outbreak in Hamburg, Altoona saved by slow sand filters. a. Cholera b. Dengue c. Spanish Flu d. Typhoid Fever

13. Which of the following is not true about slow sand filtration?

a. Slow sand filters use biological processes to clean the water, and are non-pressurized systems. b. Slow sand filters do not require chemicals or electricity to operate. c. Slow sand filters require relatively low turbidity levels to operate efficiently. d. Slow sand filters produce water at a rapid, constant flow rate and are usually used in conjunction

with a storage tank for peak usage.

14. Typical depth of a slow sand filter is _____________ deep a. 0.5-1 meters b. 1-2 meters c. 3-4 meters d. 1-3 meters

15. Slow sand filters are often the preferred technology in many developing countries because of a. Low energy requirement b. Robust performance c. Low initial cost d. a & b e. b & c

16. ______________ is a hard, compact variety of mineral coal that has a high luster. It has the

highest carbon content, the fewest impurities, and the highest calorific content of all types of coal, which also include bituminous coal and lignite. a. anthracite b. zeolite c. calcite d. albite

17. The following are the advantages of a slow sand filter except

a. SSF require little or no mechanical power, chemicals or replaceable parts. b. SSF require minimal operator training and only periodic maintenance c. SSF are often an appropriate technology for poor and isolated areas d. SSF due to their simple design, may be created DIY. e. All of the above f. None of the above

18. The duration of slow sand filters runs depends on water quality and loading rates. Ideally, the raw water

turbidity should be less than _____________. a. 5 NTU b. 10 NTU c. 15 NTU d. 20 NTU

19. Recent improvement that some systems have adopted to improve filters performance include the

inclusion of a GAC layer within the media to absorb organic chemicals and preozonation ahead of the filter as another means of improving the removal of organics. GAC means a. granular aerated carbon b. granular activated carbon c. granulated aerated carbon d. granulated activated carbon

20. The percentage of bacterial removal in a slow sand filtration is

a. 97.9 – 98.99 % b. 98.9-99 % c. 98.9 – 99.99 % d. 99.9 – 99.99 %

21. It is a condition where the incoming water forms a cavity in the filter bed in which the cavity causes the filter bed to become thinner locally, allowing water to pass more easily through the bed. a. Inflow b. Preferential Flow c. Backflow d. None of the above

22. Installed under the sand layers in the filter prevents filter sand from being lost during filtration

a. Sand filter b. Underdrain System c. Gravel Support d. Perforated pipes

23. These have three types of media, usually crushed anthracite coal, sand, and garnet. a. Sand b. Multi-media Filter c. Dual-Media Filter d. All of the above

24. __________ is accomplished by reversing the flow through the filter where a sufficient flow of wash

water is applied until the granular filtering medium is fluidized(expanded), causing the particles of the filtering medium to abrade against each other.

a. Backwashing b. Pre-washing c. Sand Treatment d. B and C

25. A reservoir for storage of filter effluent

a. Drilled Well b. Dug Well c. Clear Well d. Driven Well

26. These form on the surface of filters when adhesive materials cause particles out of the water and media grains to stick together.

a. Mudballs b. Damping c. Flocs d. Filtrate

27. The height in which the media rises during backwashing is __________.

a. Bed Expansion b. Bed Intrusion c. All of these d. None of these

28. The formation of bubbles takes place which stick to the sand grains when negative pressure is developed, it tends to release the dissolved air and other gases present in water.

a. Air break b. Aeration c. Aerated media d. Air binding

29. The country of origin of Rapid Sand Filtration a. Netherlands b. Germany c. U. S. A d. Rome

30. A system consists of a series of clay or plastic blocks that form the channels to remove the filtered

water from the filter and distribute the backwash water

a. Pipe laterals b. False Floor c. Water wash trough d. Leopold

31. _______ collect backwash water and carry it to the drain system a. Pipe laterals b. False Floor c. Water wash trough d. Leopold

32. The effective sand size for rapid sand filtration

a. 0.4-0.7 cm b. 4-7mm c. 0.4-0.7mm d. 4-7 cm

33. The type of underdrain system which uses a control manifold with several perforated laterals on each side to allow backwash to be directed against the floor, which helps keep gravel and sand beds from being directly disturbed by the high velocity water jets. a. Pipe laterals b. False Floor c. Water wash trough d. Leopold

34. The following are disadvantages of rapid sand filter except a. Turbid water may be treated b. Land required is less compared to slow sand filter c. Operation is continuous. d. All of the above e. None of the above

35. Which of the following condition does not require backwashing?

a. The head loss is low and the filter produces water at the desired rate; b. Floc starts to break through the filter and the turbidity in the filter effluent increases; c. A filter run reaches a given hour of operation. d. None of these

36. The following are RSF based on filter material except:

a. Sand filters b. Anthracite filters c. Diatomaceous earth filters d. All of the above e. None of the above

37. The cracking of the filter media and/or separation of the media from the filter wall.

a. Breakthrough b. Air Binding c. Preferential Flow d. Bed Expansion

38. Supports the filter sand and is usually graded in three to five layers, each generally 6-18 inches in thickness, depending on the type of underdrain used. a. Sand filter b. Underdrain System c. Gravel Support d. Perforated pipes

39. Allows backwash to be directed against the floor, which helps keep gravel and sand beds from being

directly disturbed by the high velocity water jets.

a. Pipe laterals b. False Floor c. Water wash trough d. Leopold

40. Which of the following is not true about Rapid Sand Filtration operation?

a. The capital cost is high while its running cost is low. b. It requires expert supervision to operate. c. The operation is continuous and requires only few minutes of cleaning. d. A & B e. All of these f. None of these

41. Which of the following is true about Rapid Sand Filtration?

a. It involves purely physical treatment process. b. It requires adequate pre-treatment like flocculation and coagulation c. It requires large area d. B & C e. All of these f. None of these

42. The common shape of a filter tank

a. Rectangular b. Circular c. Either a or b d. a and b

43. What does NTU means? a. Nephelometric Turbidity Units c. Nephrometric Turbidity Units b. Nephrotoxic Units d. None of these

44. Which of the following causes breakthrough?

a. running the filter at an excessive filtration rate b. extending filter runs too long between backwashing c. uneven distribution of water over the filter surface d. a & b e. All of the above

45. Aside from wastewater tertiary treatment, rapid sand filtration is also commonly used in treating _____.

a. Ground water b. Surface water c. Saline water d. None of these

46. Occurs within the interstices of the filter medium. a. flocculation b.adhesion c. interception d. impaction

47. Particles became attached to the surface of the filtering medium as they pass by. a. flocculation b. adhesion c.interception d. impaction

48. Many particles that move along the streamline are removed when they came in contact with the

surface of the medium. a. flocculation b. adhesion c. interception d. impaction

49. Heavy particles will not follow the streamlines.

a. flocculation b. adhesion c. interception d. impaction

50. Particles settle on the filtering medium within the filter. a. flocculation b) adhesion c.interception d. sedimentation

51. Mechanism where particles smaller than the pore space are trapped within the filter

a. Mechanical straining b. Chance Contact c. Interception d. Impaction

52. Which of the following are reasons for measure filter performance: a. To know the particle removal efficiency b. To know the headloss across the packed bed c. To know the required pre-treatment processes d. A & B e. B & C

53. Usually made out of reinforced concrete, filled with sand and gravel to the height of 1.5-2 metres

a. Chamber box b. aeration tank c. sedimentation tank d. chlorine-contact tank

54. Distributes the backwash water evenly across the total filter a. Sand filter b. Underdrain System c. Gravel Support d. Perforated pipes

55. Typical head loss in a well maintained rapid sand filtration system

a. 1-3 ft b. 4-5 ft c. 9-10 ft d. 6-8 ft

56. What river is used as water supply in early 1800s in Britain?

a. River Eamont b. River Thames c. River Severn d. River Clyde

57. An engineer who introduced the use of slow sand filtration in Britain during the early 1800s is ______. a. Bart Simpson b. James Simpson c. Homer Simpson d. Marge Simpson

58. A conical cloth filter bag used in early water filtration.

a. Archimedean Sleeve b. Da Vinci Sleeve c. Hippocratic Sleeve d. Whittaker Sleeve

59. _______ is a chemical that is added to destabilized particles and accomplish coagulation a. coagulant b. asphyxiant c. sediment d. floc

60. Which of the following is used in washing sand media of a slow sand filtration?

a. Nichols washer b. Blaisdell machine c. All of these d. None of these

Enumeration: 1-3. (3) Classification of filtration. Ans: Depth Filtration, Surface Filtration, Membrane Filtration 4-7. Classification of Depth Filtration.

Ans: Slow Sand Filtration, Rapid Sand Filtration, Intermittent Porous Medium Filtration, Recirculating Porous Medium Filtration

8-13. (6) Removal mechanism of depth filtration. Ans: Straining, Sedimentation, Impaction, Interception, Adhesion, Flocculation

14-15. Removal mechanism of straining. Ans: Mechanical, Chance Contact