Water Distro 2 set 2

Card Set Information

Water Distro 2 set 2
2014-05-31 21:28:33
Water Distribution
water distribution
Show Answers:

  1. Free chlorine residual in water exists in two
    forms.  These are
    • Hypochlorous acid
    • and hypochlorite ion
  2. When sodium hypochlorite is dissolved in water, which of the following is formed?
    • Sodium hydroxide
    • (lye, or caustic soda)
  3. The sum of a disinfectant’s demand and its residual is equal
    to the
    Applied dosage
  4. When chlorine gas is dissolved in water, two products are formed: hypochlorous acid and
    Hydrochloric acid
  5. The difference between the total chlorine
    applied and the chlorine residual is
    Chlorine demand
  6. The device used to regulate and control the rate of feed of chlorine gas is called a
  7. Chlorine residual is measured in the field using the
    DPD colorimetric method
  8. The fusible plug that is in all chlorine containers
    Should never be removed or tampered with
  9. The device that generates the vacuum conditions for chlorine gas application is called a
  10. A chlorine leak can be detected by
    Applying ammonia gas
  11. A “B” repair kit is used to address equipment failures on
    • One-ton chlorine
    • containers
  12. When chlorine gas is to be withdrawn from a one-ton container, you must use the
    Upper valve
  13. A chlorinator is feeding 240 pounds per day at a treatment plant operating at 24 MGD. 

    What is the current chlorine dosage rate in milligrams per liter?
    mg/L         =          lb/day  ÷ (8.34  x  MGD)

    •    =          240       ÷ (8.34  x  24)

       =          1.2 mg/L
  14. A treatment plant’s desired chlorine dosage rate is 3.5mg/L, and its current flow rate is 8000 gallons per minute. 

    What should the pounds per day setting be on
    the plant’s chlorinator?
    lb/day        =          mg/L x  8.34  x (MGD)

    =          3.5  x  8.34 x  (8000 gal/min x 1440 min/day ÷1,000,000 gal/Mgal)


                      =          336 lb/day
  15. At the top of the “hump” in the chlorine breakpoint curve,
    • All ammonia has
    • been converted to chloramines
  16. A distribution system operator measures a total chlorine residual of
    1.25 mg/L, and a free chlorine residual of 1.15 mg/L.  This indicates that
    The system is operating to the right of the breakpoint on the breakpoint curve
  17. From the first rising portion of the chlorine breakpoint curve through the top of the “hump”, the predominant form of residual chlorine is
  18. In addition to indicating that bacteria may be present, nitrite acts as a
    • Dechlorinating
    • agent
  19. Of the following, which will have the greatest tendency to increase

    a.System pressures

    b. Pipe materials

    c.Water sources

    d.Water age

    e. Diurnal variation
    Water age
  20. At what point on the breakpoint curve are we most likely to encounter
    Near the breakpoint
  21. In nitrification, bacteria consume excess ammonia in the water and produce
  22. A distribution system operator measures a total chlorine residual of 1.25 mg/L.  How many points on the chlorine breakpoint curve may display this residual?
  23. When free chlorine is applied at a ratio of more than 5:1 versus
    ammonia, chloramines will always be
    Converted into nitrogen gas and nitrate
  24. At the top of the “hump” in the chlorine breakpoint curve, the
    chlorine-to-ammonia ratio is
  25. A small amount of free chlorine is added to a water sample, but no chlorine residual is apparent.  This is most likely due to the presence of which of the following in the raw water?
    • Iron and/or
    • hydrogen sulfide
  26. Which of the following can be added along with chlorine to form
    Aqueous ammonia
  27. The total amount of free chlorine required to reach the breakpoint is known as the chlorine
  28. Nitrification in distribution systems using chloramines requires the presence of
    Free ammonia
  29. A new reach of 36-inch pipe containing 0.029 million gallons needs to
    be disinfected with chlorine, using 50 mg/L. 
    How much chlorine gas must be applied in this procedure?
    • a.                 
    • 12 pounds =50 x 0.029 x 8.34
  30. A reservoir requires 1000 pounds of chlorine gas for full
    disinfection.  How many pounds of calcium
    hypochlorite granules (65% available chlorine) will this procedure require?
    • a.                 
    • 1540 pounds  = 1000 pounds ÷ 0.65
  31. A 1.5 million gallon reservoir requires a dosage of 10 ppm for disinfection.  How many gallons of bleach (12.5% available chlorine, 9.5 lb/gal) will this procedure require?
    105 gallons  = (10 x 1.5 x 8.34) ÷ 0.125 ÷ 9.5
  32. The total static head plus friction is a pump’s
    Total dynamic head
  33. Compared to axial flow pumps, radial flow pumps will exhibit a
    Lower flow rate and a higher discharge pressure
  34. The difference between water pressures upstream and downstream of a
    pump when it is not in operation is known as the
    Total static head
  35. The water in a pump’s packing gland serves many purposes.  Among these is that it
    Flushes gritty material out of the packing area
  36. The purpose of the packing in a centrifugal pump is

    Comparable to a bearing since it is impregnated with lubricant

    b. To prevent vibration of the shaft

    c. To provide support for the impeller

    d. To surround the bearings and lubricate them

    e.None of the above
    None of the above
  37. Which of the following is a positive displacement pump?
    Piston pump
  38. The practical maximum suction lift for a centrifugal pump in good condition
    20-feet to 25-feet
  39. A type of pump that can cause discharge line rupture from over-pressurizing is
    Positive displacement
  40. Pumps are primed to
    • Replace air inside
    • the pump with water
  41. A
    term for the water-containing portion of a centrifugal pump is the
  42. 1.                 
    Which of the
    following is considered a radial flow pump?

    Rotary lobe

    Vertical turbine


    Air lift

    Mixed flow
  43. Vertical turbine
  44. A pump is operating in a flow range that provides an efficiency of 80 %.  The 50 Hp electric motor that drives this
    pump has an efficiency of 90 %.  What is
    the wire-to-water efficiency of this installation?
    • a.                 
    • 72 percent    =     0.80 x  0.90  x 100%
  45. Find the motor horsepower required for a pump that must move 1200 gpm against a TDH of 150 feet, if the pump efficiency is 75% and the motor efficiency is 90%.
    • a.                 
    • 67 Hp =(1200 x 150 ÷ 3960)  ÷ 0.75  ÷  0.90
  46. Find the daily cost of operation of a 100-Hp pump, assuming continuous (24-hour) operation and
    an electrical cost of 20 cents per kilowatt-hour.
    $358 = 100 Hp x 0.746 kW/Hp  x  24 hr 

    x $0.20/kWhr
  47. The formal document describing the potential impact of a hazardous material release on a utility’s neighbors, and which must be
    submitted to the Federal Bureau of Investigation, is called the
    Risk management plan
  48. Which of the following gases is toxic at the lowest concentration?
    Hydrogen sulfide
  49. Shoring is normally required for trenches of what minimum depth?
  50. Egress is normally required for trenches of what minimum depth?
  51. Which of the following would be considered a primary instrument?

    a. Flow meter

    Pressure sensor

    c. Level detector

    d.Chlorine residual analyzer

    e.All of the above
  52. All of the above
  53. Which of the following is the most likely to be a fuel involved in a Class B fire?
  54. A confined space that contains a material that has the
    potential to engulf an entrant is
    A permit space
  55. The cost of parts and labor for a new pump station is an example of
    Capital expenses
  56. What condition must exist for an area to be considered a confined space?

    a.Limited or restricted means of entry or exit

    Is large enough for a person to enter and perform work

    c.Is not designated for continuous occupancy

    d.All of the above

    e.None of the above
    All of the above
  57. The costs of maintenance labor and electricity for pump
    operations are examples of
    Operational expenses
  58. The progressive discipline procedure dictated by the Skelly process consists of
    Counseling, verbal warning, written warning, suspension, and termination
  59. A tank has an actual water level of 26 feet, and a maximum water level of 32 feet.  What
    should be the milliamp reading for the level gauge located at the tank bottom?
    17 ma =  [ 16 ma  x  (26ft ÷ 32 ft) ]  +  4 ma