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Water Treatment > Treatment Task > Flashcards

Treatment Task Flashcards

1
Q

Which precipitates can foul a cation exchange resin?

a. Sodium chloride and potassium chloride
b. Chlorate and borate
c. Sulfates
d. Iron and manganese

A

d. Iron and manganese

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2
Q

Which process works best for sequestering manganese?

a. Sodium silicate alone
b. Sodium silicate and chlorine
c. Polyphosphate alone
d. Polyphosphate and chlorine

A

d. Polyphosphate and chlorine

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3
Q

When should polyphosphates used for sequestration of iron and manganese from a well be injected into the process?

a. Right after disinfection
b. Immediately after aeration to remove unwanted gases
c. Right after clarification
d. Right after the water leaves the well

A

d. Right after the water leaves the well

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4
Q

Recarbonation is _______.

a. adding CO2 to the water.
b. adding bicarbonate to the water.
c. adding acid to precipitate the excess lime.
d. adding caustic soda.

A

a. adding CO2 to the water.

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5
Q

In the ion-exchange softening process, once the resin can no longer soften water it must be ________.

a. renewed.
b. re-catalyzed.
c. regenerated.
d. recharged.

A

c. regenerated.

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6
Q

Ion exchange processes can typically be used for direct groundwater treatment as long as turbidity and ________ levels are not exessive.

a. calcium carbonate
b. iron
c. carbon dioxide
d. sodium sulfate

A

b. iron

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7
Q

Softened water has a high pH and a high concentration of CaCO3. Therefore, stabilization is essential in order to prevent the CaCO3 from precipitating out _________.

a. in household plumbing.
b. in the clear well.
c. in the distribution system.
d. on the filters.

A

d. on the filters.

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8
Q

Which is the best type of salt to use in the regeneration of ion exchange softener resin?

a. Fine-grained salt
b. Block salt
c. Block or road salt
d. Rock salt or pellet-type salt

A

d. Rock salt or pellet-type salt

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9
Q

Powdered activated carbon is primarily used to control __________.

a. disinfectant by-products.
b. organic compounds responsible for tastes and odors.
c. synthetic organic chemicals.
d. humic and fulvic acids.

A

b. organic compounds responsible for tastes and odors.

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10
Q

Ion exchange will remove _________.

a. all hardness.
b. all hardness down to 7.4 mg/L, as CaCO3.
c. all hardness down to 17.2 mg/L, as CaCO3.
d. all hardness down to about 25.0 mg/L, as CaCO3.

A

a. all hardness.

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11
Q

It is impossible to produce water with a hardness of less than ______ when using the lime-soda ash process.

a. 9 mg/L
b. 17 mg/L
c. 25 mg/L
d. 50 mg/L

A

c. 25 mg/L

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12
Q

When added to water for softening purposes, soda ash will do which of the following?

a. Disinfect the water and kill the vast majority of protozoans, viruses, bacteria, and other multicellular organisms.
b. Raise the pH of water to between 8.0 and 9.8 pH units.
c. Add CO2 to the water.
d. Add calcium alkalinity to the water.

A

a. Disinfect the water and kill the vast majority of protozoans, viruses, bacteria, and other multicellular organisms.

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13
Q

Magnetic ion exchange resin has been developed to remove _________.

a. total organic carbon.
b. chlorides.
c. iron and magnesium.
d. sulfates and sulfides.

A

a. total organic carbon.

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14
Q

Approximately how much carbon is lost during the reactivation process for granular activated carbon?

a. 5%
b. 7%
c. 10%
d. 15%

A

a. 5%

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15
Q

Which is the most advantageous application point for powdered activated carbon?

a. Raw water intake
b. After coagulation
c. After oxidation with chlorine
d. In the filters

A

a. Raw water intake.

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16
Q

Which is the most effective method for removing tastes and odors?

a. Coagulation, sedimentation, and filtration
b. Granular activated carbon
c. Anion exchange
d. Lime softening

A

b. Granular activated carbon

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17
Q

Backwashing rate procedures should be reassessed to determine the cause of granular activated carbon loss if the loss per year exceeds ________.

a. 2 inches.
b. 4 inches.
c. 6 inches.
d. 8 inches.

A

a. 2 inches.

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18
Q

Which is the most efficient process for the removal of nitrite and nitrate?

a. Powdered activated carbon
b. Granular activated carbon
c. Anion exchange
d. Cation exchange

A

c. Anion exchange

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19
Q

Which is the main problem if particle agglomeration is occurring in a filter or iron and manganese removal at the interface of the coal layer and the layer below?

a. Oxidant is too weak
b. Coagulant dosage is excessive
c. Coal layer is too fine
d. Coal layer is too coarse

A

d. Coal layer is too coarse

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20
Q

Which is the most effective method for the removal of disinfection by-products?

a. Reverse osmosis
b. Lime softening
c. Ultrafiltration
d. Granular activated carbon

A

d. Granular activated carbon

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21
Q

Softener resin is regenerated by passing a sufficient volume an concentration of which through the resin bed?

a. Caustic soda
b. Dilute hydrochloric acid
c. Brine
d. Sodium sulfate

A

c. Brine

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22
Q

Sequestration is a process in which iron and manganese are _________.

a. precipitated with a chemical, but not filtered out of the water.
b. kept in solution by certain chemicals.
c. oxidized and thus made insoluble.
d. reduced and thus made insoluble.

A

b. Kept in solution by certain chemicals.

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23
Q

Which chemical is often used with lime softening?

a. Ferric chloride
b. Ferric sulfate
c. Sodium aluminate
d. Sodium silicate

A

b. Ferric sulfate

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24
Q

If sequestration of iron and manganese is used, the chlorine residual in the water system should always be maintained at or above _________.

a. 0.2 mg/L
b. 0.4 mg/L
c. 0.5 mg/L
d. 1.0 mg/L

A

a. 0.2 mg/L

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25
Q

Which must be added for the magnesium carbonate hardness in the softening process?

a. Lime
b. Two times as much lime
c. Soda ash
d. Lime and soda ash

A

b. Two times as much lime

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26
Q

Which must be added for magnesium noncarbonated hardness in the softening process?

a. Lime
b. 2 times as much lime
c. Soda ash
d. Lime and soda ash

A

d. Lime and soda ash

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27
Q

Once the ion-exchange resin can no longer remove hardness, it is said to be _________.

a. wasted.
b. consumed.
c. expended.
d. exhausted.

A

d. exhausted.

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28
Q

Which of the following is the most effective method for the removal of hardness?

a. Granular activated carbon
b. Lime softening
c. Anion exchange
d. Coagulation, sedimentation, and filtration

A

b. Lime softening

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29
Q

When should polyphosphates be added to the process to control iron and manganese?

a. 20 to 30 minutes before chlorine addition
b. A few minutes before chlorine application
c. At the same time as chlorine application
d. 20 to 30 minutes after chlorine addition

A

b. A few minutes before chlorine application

30
Q

The major advantage for using activated silica is that it will _________.

a. reduce sensitivity to pH changes.
b. inhibit bacterial growth.
c. increase alkalinity.
d. strengthen the floc.

A

d. strengthen the floc.

31
Q

Which chemical is used to stablilize water after it has been lime-softened?

a. Sulfuric acid
b. Carbon dioxide
c. Sodium hydroxide
d. Zinc orthophosphate

A

b. Carbon dioxide

32
Q

Sodium polyphosphate ____________.

a. will produce a protective coating.
b. will increase pH and alkalinity.
c. is a sequestering agent.
d. is a coagulant aid.

A

c. is a sequestering agent.

33
Q

Usually, raw water can be softened with lime alone when it contains _________.

a. mostly calcium hardness.
b. mostly magnesium hardness.
c. very little carbonate hardness.
d. little or no noncarbonated hardness.

A

d. little or no noncarbonated hardness.

34
Q

In the lime-soda ash softening process, the soda ash dosage is based __________.

a. only on carbonate and magnesium hardness to be removed.
b. on carbonate hardness and carbon dioxide to be removed.
c. primarily on noncarbonated and magnesium hardness.
d. only on the amount of noncarbonated hardness to be removed.

A

d. only on the amount of noncarbonated hardness to be removed.

35
Q

Powdered activated carbon is usually added to the treatment process __________.

a. before the normal coagulation-flocculation step.
b. before the sedimentation basin.
c. after the sedimentation basin.
d. in the filters.

A

a. before the normal coagulation-flocculation step.

36
Q

Softening resin exchanges what for the calcium and magnesium that it removes from the water?

a. Sodium
b. Hyroxide
c. Potassium
d. Hydrogen ions (H+)

A

a. Sodium

37
Q

Sequestration of iron and manganese prevents them from being _________.

a. oxidized and made insoluble.
b. reduced and made insoluble.
c. reduced and made soluble.
d. utilized by bacteria.

A

a. oxidized and made insoluble.

38
Q

Ion exchange processes can typically be used for direct groundwater treatment as long as turbidity and _________ levels are not excessive.

a. calcium carbonate
b. iron
c. carbon dioxide
d. sodium sulfate

A

b. iron

39
Q

Which color is oxidized iron?

a. Yellow
b. Brown
c. Red
d. Dark brown

A

c. Red

40
Q

Recarbonation after lime-soda ash softening is required to remove calcium carbonate that is in suspension to prevent __________.

a. deposition of the calcium carbonate in the clear well and distribution system.
b. scale formation in distribution piping.
c. customer complaints of turbidity and color.
d. cementation of filter media.

A

d. cementation of filter media.

41
Q

Which chemical will cause corrosion if overfeeding occurs?

a. Sodium hydroxide
b. Carbon dioxide
c. Sodium hexametaphosphate
d. Tetrasodium polyphosphate

A

b. Carbon dioxide

42
Q

Which would be the best chemical treatment or method to use to effectively reduce the concentration of taste-and-odor compounds caused by actinomycetes species?

a. Activated carbon adsorption
b. Chlorine
c. Potassium permanganate
d. Chlorine dioxide

A

a. Activated carbon adsorption

43
Q

The process of decomposing a substance by electricity is called _________.

a. cathodic corrosion.
b. galvanic corrosion.
c. electrolysis.
d. ionization.

A

c. electrolysis.

44
Q

Sequestration is effective only for groundwater that has relatively low levels of dissolved iron and manganese and _________.

a. no dissolved oxygen.
b. no carbonate hardness.
c. is slightly acidic.
d. is slightly basic.

A

a. no dissolved oxygen.

45
Q

Which treatment procedure should be followed after a well has been shock chlorinated?

a. An alkaline neutralization solution should be added
b. Oxygen gas should be bubbled throughout the well water
c. A dissolution-dispersion step using acidification and surfactants
d. Three well volumes should be purged to flush the well and reduce the chlorine concentration

A

c. A dissolution-dispersion step using acidification and surfactants

46
Q

Which type of hardness usually calls for a two-stage softening process?

a. Calcium hardness above 100mg/L
b. Magnesium hardness
c. Noncarbonated hardness
d. Carbonate hardness

A

c. Noncarbonated hardness

47
Q

The activated alumina process is sensitive to _________.

a. humic substances.
b. pH.
c. high total dissolved solids.
d. fluoride.

A

b. pH.

48
Q

How much will the alkalinity of the treated water increase for each mg/L of lime added?

a. 0.42 mg/L
b. 0.64 mg/L
c. 1.00 mg/L
d. 1.28 mg/L

A

d. 1.28 mg/L

49
Q

When should core samples be collected from filters using granular activated carbon?

a. Every six months
b. At the time of installation and every six months thereafter
c. Every year after installation
d. At the time of installation and every year thereafter

A

b. At the time of installation and every six months thereafter

50
Q

Which of the following is the best process to remove lead?

a. Activated alumina
b. Anion exchange
c. Chemical oxidation
d. Lime softening

A

d. Lime softening

51
Q

The ion exchange softening process does not alter which properties of the water?

a. Chloride and bromide concentrations
b. pH and alkalinity
c. Heavy metals concentrations
d. Nitrogen and phosphorus concentrations

A

b. pH and alkalinity

52
Q

A flocculant is required for iron removal if most of the iron passes through a ________ filter membrane.

a. 5 µm
b. 10 µm
c. 15 µm
d. 20 µm

A

a. 5 µm

53
Q

Which would be the most probable solution to control algae in the water plant if the algae were clogging the filters?

a. Add copper sulfate before the filters
b. Use activated carbon
c. Increase backwashing rate and frequency
d. Add a long chain polymer filter aid

A

b. use activated carbon

54
Q

Activate silica is prepared by the water treatment operator. Which is the actual chemical that is delivered to the water treatment plant?

a. Na2SiO3
b. Ca2SiO4
c. Al2SiO5
d. K2SiO3

A

a. Na2SiO3

55
Q

Raw water requires both lime and soda ash when there are nominal amouts of which type of hardness in the water?

a. Magnesium hardness
b. Iron hardness
c. Calcium hardness
d. Manganese hardness

A

a. Magnesium hardness

56
Q

The double-stage process in excess-lime softening _________.

a. causes greater removal of iron.
b. accomplishes greater removal of magnesium.
c. eliminates the need for soda ash for removing noncarbonated hardness.
d. removes the recarbonation requirement.

A

b. accompliches greater removal of magnesium.

57
Q

The reaction CO2 + CaCO3 + H2O is complete when the pH reaches _________.

a. 7.6.
b. 8.0.
c. 8.3.
d. 8.5.

A

c. 8.3.

58
Q

Trihalomethanes can form along with other disinfectant by-produsts due to lime, excess lime, or lime soda ash softening of water because of the _________.

a. temperature produced in the process increasing chemical reactions.
b. high pH that is required to operate the process.
c. coagulants used along with the softening process.
d. gases produced in the process reacting with organics acids in the water.

A

b. high pH that is required to operate the process.

59
Q

When backwashing an ion exchange unit, how much should the bed expand from water introduced from the bottom of the ion exchange column?

a. 25 to 35%
b. 35 to 50%
c. 50 to 75%
d. 75 to 85%

A

c. 50 to 75%

60
Q

Which bed expansion during backwashing must be achieved for filters using granular activated carbon?

a. 20%
b. 25%
c. 30%
d. 50%

A

d. 50%

61
Q

Which type of aerator causes aeration to occur in splash areas and can be used to oxidize iron and to partially reduce dissolved gases?

a. Slat-and-coke-tray aerator
b. Packed tower
c. Cascade aerator
d. Cone aerator

A

c. Cascade aerator

62
Q

Which type of aerator is much more efficient in removing dissolved gases and for oxidizing iron and manganese?

a. Packed tower
b. Slat-and-coke-tray aerator
c. Cascade aerator
d. Draft aerator

A

d. Draft aerator

63
Q

The lime-soda ash softening process is enhanced best with which other application?

a. Increase alkalinity with caustic soda
b. Aeration
c. Solids-contact unit
d. Oxidation with chlorine

A

c. Solids-contact unit

64
Q

After first stage recarbonation, which is almost completely dissolved?

a. Calcium crystals
b. Calcium carbonate crystals
c. Magnesium crystals
d. Magnesium carbonate crystals

A

b. Calcium carbonate crystals

65
Q

Which are the exchange capacities of natural zeolites?

a. 1 to 2 kilograins/ft3
b. 3 to 5 kilograins/ft3
c. 5 to 8 kilograins/ft3
d. 9 to 12 kilograins/ft3

A

b. 3 to 5 kilograins/ft3

66
Q

Which best describes the purpose of granular activated carbon?

a. Particulate removal and particulate adsorption
b. Particulate screening and particulate absorption
c. Particulate absorption and particulate removal
d. Particulate adsorption and particulate absorption

A

a. Particulate removal and particulate adsorption

67
Q

Which is the best process for removing trihalomethanes?

a. Activated alumina
b. Coagulation, sedimentation, and filtration
c. Anion exchange
d. Aeration and stripping

A

d. Aeration and stripping

68
Q

The most common cation exchange resins are _________.

a. weak-base resins.
b. strong-base resins.
c. weak-acid resins.
d. strong-acid resins.

A

d. strong-acid resins.

69
Q

Sequestration of iron and manganese is usually not recommended for waters where the concentration of iron, manganese, or both exceeds _________.

a. 1.0 mg/L.
b. 2.0 mg/L.
c. 3.0 mg/L.
d. 5.0 mg/L.

A

a. 1.0 mg/L.

70
Q

Which coagulant aids use extremely small dosages?

a. Polyelectrolytes
b. Activated alumina
c. Weighing agents
d. Aluminum chloro-hydrate (ACH)

A

a. Polyelectrolytes

71
Q

The design parameter for predicting granular activated carbon (GAC) performance is called ___________.

a. empty-bed contact time.
b. GAC saturation point.
c. GAC potential.
d. GAC saturation potential.

A

a. empty-bed contact time.

72
Q

Which is the most effective method for the removal of synthetic organic chemicals?

a. Lime softening
b. Granular activated carbon
c. Aeration and stripping
d. Chemical oxidation

A

b. Granular activated carbon

Water Treatment (16 decks)

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