Water Treatment Grade 2 Flashcards
(225 cards)
1
Q
Molarity is the number of
a. gram equivalent weights of solute per liter of solution.
b. gram atomic weight per oxidation number.
c. moles of solute per kilogram of solvent.
d. moles of solute per liter of solution.
A
d. moles of solute per liter of solution.
2
Q
“CaCO3” is the _____ of calcium carbonate.
a. chemical symbol
b. atomic formula
c. chemical formula
d. chemical equation
A
c. chemical formula
3
Q
The first step in calculating percent by weight of an element in a compound is to determine the
a. percent by weight.
b. molecular weight.
c. chemical equation.
d. coefficient.
A
b. molecular weight.
4
Q
What term refers to the equivalent number of weights of solute per liter of solution?
a. Normality
b. Equivalent weight
c. Molecular weight
d. Coefficient
A
a. Normality
5
Q
A solution consists of 2 parts: a solvent and a
a. diluent.
b. solute.
c. concentrate.
d. suspension.
A
b. solute.
6
Q
How many minutes are there in a day?
A
1 day = 1,440 minutes
7
Q
How many gallons of water are in a cubic foot?
A
1 cubic foot = 7.48 gallons
8
Q
What equation is used to calculate the volume (in cubic feet) of a circular basin or tank?
A
Volume = .785 x Diameter Squared x Depth = Cubic Feet
9
Q
What equation is used to find the volume (in cubic feet) of a square/rectangle basin or tank?
A
Volume = Length x Width x Depth = Cubic Feet
10
Q
What equation would you use to calculate the number of gallons in a tank or basin?
A
Total Gallons = Cubic Feet (tank or basin volume) x 7.48 gallons per cubic foot
11
Q
1 Gallon = ______ mL
A
1 Gallon = 3,785 mL
12
Q
How would you calculate the Detention Time (in hours) of water in a basin or tank?
A
Hours of Detention Time = Volume (gallons) in Basin divided by Flow Rate in gallons per hour
13
Q
How would you convert Gallons per Minute (gpm) to Millions of Gallons per Day (MGD)?
A
GPM to MGD = GPM x 1,440 minutes per day then divided by 1,000,000 gallons
14
Q
What Equation is used to find the Chemical Feed Rate in Pounds per Day?
A
Pounds per Day = Dosage (mg/L) x MGD x 8.34 pounds per gallon divided by % of chemical (x % purity of the chemical)
15
Q
How do you calculate the Filtration Rate (gallons per minute per square foot)?
A
Filtration Rate (gpm/ft2) = Flow Rate (gpm) divided by the Filter Surface Area (ft2)
16
Q
Pressure measured in terms of the height of water (in meters or feet) is referred to as
a. gauge pressure.
b. head.
c. barometric pressure.
d. absolute pressure.
A
b. head.
17
Q
How is Volume calculated?
A
Surface Area (ft2) x a third dimension
18
Q
In the equation to convert milligrams-per-liter concentration to pounds per day, (dosage) (flow rate) (conversion factor) =
a. feed rate.
b. feed demand.
c. feed capacity.
d. total feed.
A
a. feed rate.
19
Q
What is the formula for calculating the area (ft2) of a circle?
A
.785 x Diameter squared
20
Q
What is the action level for copper?
a. 0.5 mg/L
b. 1.0 mg/L
c. 1.3 mg/L
d. 1.8 mg/L
A
c. 1.3 mg/L
21
Q
Water being served to the public for a population greater than 3,000 must not have a disinfectant residual entering the distribution system below _____ for more than 4 hours.
a. 0.5 mg/L
b. 0.2 mg/L
c. 0.3 mg/L
d. 0.4 mg/L
A
b. 0.2 mg/L
21
Q
Where are the sampling point(s) located for required sampling of turbidity in a community water system?
a. At representative points within the distribution system.
b. 75% at locations representative of population distribution and 25% at the farthest points in the distribution system.
c. At point(s) where water enters the distribution system, including all filter effluents in a surface water treatment plant.
d. At effluents of all filters in a surface water treatment plant, at entry points to the distribution system, and at locations representative of population distribution.
A
c. At point(s) where water enters the distribution system, including all filter effluents in a surface water treatment plant.
22
Q
Under the Surface Water Treatment Rule, disinfection residuals must be collected at the same location as
a. coliform samples.
b. total trihalomethanes.
c. disinfection by-products.
d. alkalinity, conductivity, and pH for corrosion studies.
A
a. coliform samples.
23
Q
What is the MCL for haloacetic acids (HAA5)?
a. 0.040 mg/L
b. 0.060 mg/L
c. 0.080 mg/L
d. 0.100 mg/L
A
b. 0.060 mg/L
24
What is the MCLG for substances that are suspected carcinogens?
Zero
25
An example of _____ is determining the lowest monthly average during 12-month monitoring of Giardia and virus inactivation.
a. benchmarking
b. profiling
c. categorizing
d. surveying
a. benchmarking
26
Which regulation is designed to limit human exposure to harmful organisms, including Cryptosporidium, by promoting achievement of particle and turbidity removal targets for surface water treatment systems?
IESTWTR (Interim Enhanced Surface Water Treatment Rule)
27
Which regulation is designed to reduce the risk of exposure to fecal contamination that may be present in public water systems that use groundwater sources?
GWR (Ground Water Rule)
28
Which regulation is designed to promote routine surveillance of distribution water quality to search for contamination from fecal matter and/or disease-causing bacteria?
TCR (Total Coliform Rule)
29
What is the optimal pH range for the removal of particle matter when using alum as a coagulant?
a. 4.5 to 5.7
b. 5.8 to 6.5
c. 6.5 to 7.2
d. 7.3 to 8.1
c. 6.5 to 7.2
30
Which forces will pull particles together once they have been destabilized in the coagulation-flocculation process?
a. van der Walls forces
b. Zeta potential
c. Ionic forces
d. Quantum forces
a. van der Walls forces
31
Which of the following is a common mistake that operators make in regard to flocculation units?
a. Allowing excessive flocculation time
b. Lack of food grade NSF-approved grease on the flocculation units
c. Keeping the mixing energy the same in all flocculation units
d. Too short of a flocculation time
a. Allowing excessive flocculation time
32
Ferric sulfate has which advantage over aluminum sulfate (alum)?
a. Less staining characteristics
b. Less cost
c. More dense floc
d. Not as corrosive
c. More dense floc
33
The lower the _____, the more difficult it is to form proper floc.
a. temperature
b. turbidity
c. pH
d. alkalinity
b. turbidity
34
Jar test results are expressed in
a. milligrams per liter (mg/L).
b. gallons per day (gpd).
c. whatever unit the treatment system has decided to use.
d. parts per million (ppm).
a. milligrams per liter (mg/L).
35
What are some characteristics of raw water that must be considered in selecting a treatment chemical?
- Type & Concentration of Contaminants
- Temperature
- pH
- Alkalinity
- Turbidity
- Color
- Total Organic Carbon (TOC)
36
Raw water temperature that approaches the freeing point has what effect on coagulation and flocculation processes?
As the water temperature decreases, the viscosity of the water increases, which slows rate of floc settling.
37
How much time is required to develop heavy floc particles during the flocculation process?
30 Minutes
38
If enteric disease-causing protozoans have been found in the effluent of a water plant, which of the following is the most probable solution?
a. Where possible, use powdered activated carbon (PAC) throughout the water plant; backwashing filters will remove the PAC.
b. Use PAC only in the sedimentation basin; backwashing the filters will remove the PAC.
c. Use the multibarrier approach - coagulation, flocculation, sedimentation, and filtration.
d. Superchlorinate the water plant.
c. Use the multibarrier approach - coagulation, flocculation, sedimentation, and filtration.
39
Conventional sedimentation has a _____ removal of Cryptosporidium oocysts.
a. less than 0.5-log
b. 0.5-log
c. 1.0-log
d. 2.0-log
a. less than 0.5-log
39
What is the major cause of short-circuiting in a sedimentation basin?
a. Open basins that are subject to algal growths and thick slime growths on the side of the basin.
b. Basins without a wind break.
c. Poor inlet baffling.
d. Density currents.
c. Poor inlet baffling.
40
Dissolved-air flotation is particularly good for removing
a. sulfides.
b. inorganics.
c. manganese and iron.
d. algae.
d. algae.
41
As solids settle to the bottom of a sedimentation basin,
a. tank pressure is reduced.
b. a sludge layer develops.
c. movement of sediment accelerates.
d. water pH decreases.
b. a sludge layer develops.
42
What are some components of a typical rectangular sedimentation basin?
- Sludge pipe
- Scum trough
- Flights
- Collector drive
- Baffle
- Adjustable effluent weirs
43
What is the maximum weir loading rate for light alum floc in solids-contact basins?
10 gpm/ft
44
Which regulation basically requires that surface water systems maintain specified C x T values before the treated water reaches the first customer?
SWTR (Surface Water Treatment Rule)
45
What is the primary test used to indicate proper sedimentation?
Turbidity
46
Which type of sludge cannot be discharged to a sanitary sewer system because its deposits might build up and block the sewers?
Lime sludge
47
Gravel displacement in a filter bed from backwash rates with too high of a velocity could eventually cause
a. compaction of the filter media.
b. loss of media into backwash troughs.
c. a sand boil.
d. bed shrinkage.
c. a sand boil.
48
If filter run times between backwashes are long (e.g., 1 week) because high-quality (low-turbidity) water is being applied to the filters, which problem could still arise?
a. Mudball formation
b. Air binding and formation of mudballs
c. Extended backwashing due to media becoming too compacted
d. Floc breakthrough
d. Floc breakthrough
49
Which conventional treatment step is eliminated by direct filtration?
a. Oxidation
b. Aeration
c. Flocculation
d. Sedimentation
d. Sedimentation
50
Which of the following is the layer of solids and biological growth that forms on the top of a slow sand filter?
a. Biosolids-film
b. Bio-carbonated scale layer
c. Schmutzdecke
d. Saprophytic layer
c. Schmutzdecke
51
Filter tanks are generally
a. spherical and constructed of steel.
b. rectangular and constructed of concrete.
c. rectangular and constructed of steel.
d. cylindrical and constructed of concrete.
b. rectangular and constructed of concrete.
52
In a typical air-scour sequence, air is applied _____ backwash water is introduced.
a. before
b. while
c. after
d. both before and after
a. before
53
What is the filtration flow rate through a high-rate mixed media filter?
3 - 8 gpm/ft2
54
Which system is the first and oldest type of underdrain system, having a central manifold pipe with perforated lateral pipes on each side?
Pipe lateral collectors
55
Prehistoric deposits of the skeletal remains of microscopic aquatic plants are the source of what useful filtering element?
Diatomaceous earth
56
Which regulation requires that all filters in a surface water treatment plant have online turbidimeters, and they monitor the filter while it is in operation?
Interim Enhanced Surface Water Treatment Rule (IESWTR)
57
The advantage to using the oxidant ozone is that it
a. is easily generated using relatively little energy.
b. is easily fed into the treatment process.
c. is noncorrosive.
d. has little pH effect.
d. has little pH effect.
58
Pretreatment with chlorine is being eliminated at many water treatment plants because it has been shown to
a. react with floc and not much with organics, pathogens, or algae; this it is a waste of resources and money.
b. react with organics almost exclusively and not much with pathogens or algae; thus it is a waste of resources and money.
c. sometimes produces disinfection by-products known to be carcinogenic.
d. react by as much as 95% of its concentration with concrete walls and metal structures before oxidizing pathogens, organics, and algae.
c. sometimes produces disinfection by-products known to be carcinogenic.
59
C x T values are based on
a. concentration of chlorine, contact time, and pH.
b. concentration of chlorine, contact time, pH, and temperature.
c. concentration of chlorine, contact time, pH, and water impurities.
d. concentration of chlorine, alkalinity, pH, and temperature.
b. concentration of chlorine, contact time, pH and temperature.
60
Which index determines the calcium carbonate deposition property of water by calculating the saturation pH where a negative value indicates corrosive water and a positive value indicates depositing water?
a. Baylis Curve
b. Langelier Saturation Index
c. Marble test
d. Ryzner index
b. Langelier Saturation Index
61
Which type of chlorine gas feeder is most commonly used?
a. Pressure
b. Combination water and pressure
c. Vacuum
d. Combination pressure and vacuum
c. Vacuum
62
Which device(s) uniformly disperse(s) the chlorine solution into the main flow of water?
a. Injectors
b. Pressure regulating valve
c. Diffusers
d. Effluent nozzles
c. Diffusers
63
The pressure in a chlorine cylinder depends on the
a. amount of chlorine in the cylinder.
b. temperature of the chlorine liquid.
c. vacuum placed on the regulator.
d. amount of gas being withdrawn.
b. temperature of the chlorine liquid.
64
Chlorine cylinders and ton containers are equipped with valves, which must comply with standards set by which organization?
The Chlorine Institute
65
A venturi device that pulls chlorine gas into a passing stream of dilution water, forming a strong solution of chlorine and water.
Injector
66
A heating device used to convert liquid chlorine to chlorine gas.
Evaporator
67
Common problems related to chlorination include:
- Chlorine leaks
- Stiff container valves
- Hypochlorinator problems
- Tastes and odors
- Sudden change in residual
- Trihalomethane formation
68
Compared to air, how dense is chlorine gas?
2.5 times as dense
69
Which of the following would immediately occur if newly installed manganese greensand was not skimmed of the fines after backwashing and stratification steps were completed?
a. Uneven flow through the bed
b. Cracks in the bed
c. Mudball formation
d. Shorter filter runs
d. Shorter filter runs
70
Manganese greensand filters can be regenerated by using
a. a surface wash and an air-water backwash.
b. brine water during backwashing.
c. potassium permanganate solution during backwash.
d. a brine solution during the first backwashing cycle followed by potassium permanganate solution for the second backwash cycle.
c. potassium permanganate solution during backwash.
71
Which material is manganese greensand and which is the coating?
a. Quartz sand coated with manganese hydroxide [Mn(OH)2]
b. Garnet sand coated with manganese dioxide [MnO2]
c. Ilmenite sand coated with manganese hydroxide [Mn(OH)2]
d. Glauconite sand coated with manganese hydroxide [Mn(OH)2]
d. Glauconite sand coated with manganese hydroxide [Mn(OH)2]
72
Depending on water temperature, what is the typical backwashing flow rate for a manganese greensand filter bed?
a. 7-8 gpm/ft2
b. 8-10 gpm/ft2
c. 10-12 gpm/ft2
d. 12-14 gpm/ft2
c. 10-12 gpm/ft2
73
The length of run for manganese greensand filters can be increased by
a. adding a high-molecular-weight polymer filter aid.
b. keeping the pH above 9.0 and lowering it after filtration.
c. keeping the pH below 7.3 and raising it after filtration.
d. adding a layer of anthracite above the greensand.
d. adding a layer of anthracite above the greensand.
74
Sequestering is effective only for groundwater with a relatively
a. low level of dissolved iron and manganese high level of dissolved oxygen.
b. high level of dissolved iron and manganese and no dissolved oxygen.
c. low level of dissolved iron and manganese and no dissolved oxygen.
d. high level of dissolved iron and manganese and high level of dissolved oxygen.
c. low level of dissolved iron and manganese and no dissolved oxygen.
75
Iron and manganese treatment strategies must be evaluated in light of which regulation?
D/DBP (Disinfection and Disinfectant By-Product Rule)
76
Which type of filter uses a special type of medium that removes iron and manganese by a combination of both, adsorption and oxidation?
Manganese greensand filter
77
Unless pilot test have shown it to be necessary, what device is needed to hold water temporarily after aeration or the addition of an oxidant?
Detention chamber or Contact chamber
78
What type of regeneration process is preferred where raw water constituents interfere with the preoxidation/filtration process?
Intermittent regeneration
79
If the natural fluoride of the raw water is variable, the concentration in the raw water should be measured
a. every 8 hours.
b. every 12 hours.
c. every day.
d. continuously.
c. every day
80
People's teeth are likely to become pitted when the fluoride concentration in drinking water goes above which amount?
a. 3 mg/L
b. 4 mg/L
c. 5 mg/L
d. 6 mg/L
b. 4 mg/L
81
How often should the fluoride concentration of treated water be measured?
a. Every 8 hours
b. Every 12 hours
c. Every day
d. Continuously
d. Continuously
82
Where should the fluoride injection point be located?
a. Right after flocculation
b. After sedimentation, but before lime softening
c. Before filtration
d. After water has received complete treatment
d. After water has received complete treatment
83
When adding fluoride, when should the fluoride level be measured to test for fluoride concentration?
Both, before and after fluoride is added
84
The operator must periodically check to ensure that at least _____ of the chemical is maintained in the saturator at all times.
a. 1-inch
b. 3-inches
c. 4-inches
d. 6-inches
d. 6-inches
85
If fluoride is added before filtration, a significant fluoride loss will occur, resulting in what?
Low fluoride readings
85
Recordings that should be maintained to monitor the fluoridation process include:
- Daily analysis of the raw water fluoride concentration (unless it is known to be stable)
- Daily analysis of finished water fluoride
- Daily records of the amount of chemical fed (in pounds or kilograms)
- Records by the operating shift of the chemical feed setting
- Daily computation of the theoretical concentration
86
Metering pumps are quite reliable, but the should receive routine maintenance according to what authority?
The manufacturer's recommendations
87
Samples to be tested for coliforms can be refrigerated for up to _____ hours before analysis, but should be done as soon as possible.
a. 4
b. 6
c. 8
d. 12
c. 8
88
Which type of sample should always be collected for determining the presence of coliform bacteria?
a. Time composite
b. Grab sample
c. Proportional
d. Composite
b. Grab sample
89
Particle counters use the principal of light
a. scattering.
b. reflection.
c. refraction
d. blockage.
d. blockage.
89
Which chemical is used to remove chlorine from the water?
a. Na2S2O3
b. Na2SiO3
c. Na2SiF6
d. NaOCL
a. Na2S2O3 (sodium thiosulfate)
90
When a water sample is acidified, the final pH of the water must be
a. <2.0.
b. <2.5.
c. <3.0.
d. <3.5.
a. <2.0.
91
Distribution samples are intended to measure the quality of the water at
a. a selected location in the system.
b. various points in the system.
c. points in the system designated by the USEPA.
d. the system's primary reservoir.
b. various points in the system.
92
Water that contains high concentrations of _____ can cause the consumption of lime when using this method of softening.
a. calcium bicarbonate
b. fluoride
c. free carbon dioxide
d. iron and manganese
c. free carbon dioxide
93
_____ is used as an oxidant for iron and manganese control, some organic precursor control, and taste-and-odor control.
a. Potassium permanganate
b. Chlorine
c. Ferric Chloride
d. Alum
a. Potassium permanganate
94
Which type of sample consists of multiple grab samples taken from the same location at different times and mixed together to make one sample?
Composite Sample
95
Which type of coagulation testing is perhaps the least understood test but, the most useful process tool available to operators?
Jar Test
96
Which index determines the calcium carbonate deposition property of water by calculating the saturation pH, where a negative indicates corrosive water and a positive value indicates depositing water?
a. Baylis curve
b. Langelier Saturation Index
c. Marble test
d. Ryzner index
b. Langelier Saturation Index
97
Which of the following composes the majority of the scale in pipe?
a. Ca(HCO3)2
b. CaCO3
c. MgCO3
d. CaSO4
b. CaCO3 (Calcium Carbonate)
98
The corrosion process can be accelerated by certain bacterial organisms because they produce which chemical?
a. N2
b. CO2
c. MgCO3
d. CaCO3
b. CO2 (Carbon Dioxide)
99
Which chemical would be best to use for corrosion inhibition if the water is very low in alkalinity and calcium concentration?
a. Sodium carbonate
b. Sodium bicarbonate
c. Sodium hydroxide
d. Polyphosphates
d. Polyphosphates
100
Stabilization refers to the treatment process used to control
a. turbidity.
b. temperature fluctuations.
c. corrosion.
d. pH imbalances.
c. corrosion.
101
In water treatment operations, corrosion can occur to some extent with
a. both plastics and metals alike.
b. almost any metal that is exposed to water.
c. all metals except cast-iron.
d. all metals except copper and stainless steel.
b. almost any metal that is exposed to water.
102
Which metal is most likely to corrode?
Magnesium
103
What are two broad classes into which corrosion in water systems can be divided?
1. Localized
2. Uniform
104
List three chemicals commonly used to increase both pH and alkalinity.
1. Lime
2. Sodium carbonate
3. Sodium hydroxide
105
The minerals that cause noncarbonate magnesium hardness are precipitated out of water by the addition of
a. carbon dioxide.
b. chlorine.
c. lime.
d. calcium bicarbonate.
c. lime
106
To reduce noncarbonate hardness, soda ash must be added to water to form
a. calcium bicarbonate.
b. carbon dioxide.
c. magnesium carbonate.
d. calcium carbonate.
d. calcium carbonate.
107
In lime softening facilities, it is normally good practice to store a minimum of _____ supply of each chemical.
a. 1 year's
b. 1 week's
c. 1 month's
d. 1 day's
c. 1 month's
108
What is the term for a conical tank in which the softening reactions take place quite rapidly as the water swirls upward through the unit?
a. Rapid-mix basin
b. Pellet reactor
c. Solids-contact basin
d. Flocculation basin
b. Pellet reactor
109
When magnesium hardness is treated with lime, what is precipitated?
Magnesium hydroxide
110
Why is soda ash needed to remove noncarbonate hardness?
To serve as an additional carbonate to form calcium carbonate
111
what happens when quicklime is added to water?
It gets hot and forms hydrated lime in a slurry
112
What is carbon dioxide used for in lime softening?
To correct the pH and stabilize the water prior to filtration
113
When magnesium hardness is treated with lime, what is precipitated?
Magnesium hydroxide
114
What federal regulation requires that samples from customers' taps be analyzed for the presence of lead and copper?
The Lead and Copper Rule
115
Which of the following 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
d. Rock salt or Pellet-type salt
116
Once the ion exchange resin can no longer remove hardness, it is said to be
a. wasted.
b. consumed.
c. expended.
d. exhausted.
d. exhausted.
117
When backwashing an ion exchange unit, how much should the bed expand from the water introduced from the bottom of the ion exchange column?
a. 25 - 35%
b. 35 - 50%
c. 50 - 75%
d. 75 - 85%
c. 50 - 75%
118
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
b. iron
119
Weak-base anion exchange resins behave much like their weak-acid counterparts; they do not remove anions above a pH of
a. 6
b. 7
c. 8
d. 9
a. 6
120
Block salt is sometimes used for home softeners, but it is not suitable for larger installations because
a. it packs tightly and does not dissolve easily.
b. the blocks required would be too heavy for operators to lift.
c. it often contains impurities.
d. its small surface does not allow it to dissolve fast enough.
d. its small surface does not let it dissolve fast enough.
121
Positively charged ions, such as calcium and magnesium, that migrate towards the cathode.
Cations
122
What is another name for the service cycle?
Operational Cycle
123
What element in source water acts as a precursor to disinfection by-production?
TOC (Total Organic Carbon)
124
Powdered activated carbon is primarily used to control
a. disinfection by-products.
b. organic compounds responsible for tastes and odors.
c. synthetic compounds.
d. humic and fulvic acids.
b. organic compounds responsible for tastes and odors.
125
GAC contactors can be used when the formation of trihalomethanes from other disinfection by-products _____ an adjustment of the disinfectants or other treatment processes.
a. can easily be controlled by
b. can be quickly reduced by
c. cannot be prevented by
d. will likely be produced by
c. cannot be prevented by
126
Which of the following happens at the surfaces of PAC particles if they are coated with coagulants or other water treatment chemicals?
a. They can emit toxic by-products
b. They lose their capacity to adsorb
c. They dissolve into the surrounding water
d. They harden and crack
b. They lose their capacity to adsorb
127
How should burning carbon be handled?
a. It should be allowed to cool without any interference
b. It should be covered in aqueous film-forming foam
c. It should be covered with a fine mist of spray from a hose or a chemical foam extinguisher
d. It should be doused with buckets of water
c. It should be covered with a fine mist of spray from a hose or a chemical foam extinguisher
128
In a slurry feed system, where should the feeder be located to ensure there is no danger that the carbon will settle out in the feed line because of the low flow velocity?
At exactly the feed point
129
In a slurry feed system, day tanks are typically made of what materials?
Fiberglass
130
Which type of aerator causes aeration to occur in splash areas and can be used to oxidize iron and partially reduce dissolved gasses?
a. Slat-and-coke-tray aerator
b. Packed tower aerator
c. Cascade aerator
d. Cone aerator
c. Cascade aerator
130
Which type of aerator is much more efficient in removing dissolved gasses and for oxidizing iron and manganese?
a. Packed tower aerator
b. Slat-and-coke-tray aerator
c. Cascade aerator
d. Draft-tube aerator
d. Draft-tube aerator
130
Which of the following is the normal air-to-water ratio at peak flow in a packed tower aerator?
a. 10:1
b. 15:1
c. 25:1
d. 35:1
c. 25:1
131
_____ aerators draw water into a blade of the aerator and throw the water into the air in tiny droplets, so that the water can pick up oxygen.
a. Surface
b. Submerged
c. Draft-tube
d. Mechanical
a. Surface aerators
132
Which type of aerator consists of a propeller-like mixing blade mounted on the end of a vertical shaft driven by a motor?
a. Submerged aerator
b. Surface aerator
c. Draft-tube aerator
d. Mechanical aerator
d. Mechanical aerator
133
In a slat-and-coke-tray aerator, the aerator is usually constructed to have sloping sides, called _____, which are used to protect the splash from wind loss and freezing.
a. splash trays
b. coke trays
c. splash aprons
d. distribution trays
c. splash aprons
134
List the typical components of a ring-type cascade aerator:
- Central feed pipe
- Splash guard
- Catch bowl
- Deflector plate
- Collector pan
- Overflow baffle
- Spray bottle
- Outlet
- Inlet
- aluminum flange
135
In general, spray aeration is successful in oxidizing iron or manganese and is very successful in increasing what characteristic of water?
Dissolved oxygen level
136
Which of the following is NOT a component of a typical hollow-fiber module?
a. Reverse osmosis membrane
b. Hollow-fiber membrane module
c. Bonded section
d. Housing
a. Reverse osmosis membrane
137
Process recovery is typically _____ percent for surface water and can be as high as ______ percent.
a. 50; 100
b. 95; 97
c. 10; 25
d. 80; 90
b. 95; 97
138
In a typical reverse osmosis flow schematic, which of the following components most closely follows the cartridge filter?
a. High-pressure pump
b. Reverse osmosis membranes
c. Water pump
d. Permeate tank
a. High-pressure pump
139
What process is defined as the ratio of the volume of product water, or permeate produced, to raw water treated?
Recovery
140
What term describes raw water that has undergone pretreatment (acidification or scale inhibitor addition) prior to entering the membrane arrays?
Feedwater
141
In a precipitative softening plant, what percentage of solids sludge is produced?
a. 1%
b. 5%
c. 10%
d. 30%
b. 5%
142
Which sludge disposal method is most economical for lime-soda ash softening plants?
a. Disposal into the sewage system
b. Sand drying beds
c. Lagoons
d. Landfill the sludge
c. Lagoons
143
What process is used to concentrate sludge?
a. Sand bed
b. Solor lagoon
c. Thickener
d. Centrifuge
c. Thickener
144
What process is used to dewater sludge?
a. Wash water basin
b. Sand bed
c. Thickener
d. Reclamation basin
b. Sand bed
145
In a rectangular basin, which type of collector uses suction pipes or a submersible pump to withdraw the sludge from the basin?
a. Travelling-bridge collector
b. Continuous sludge collector
c. Chain-and-flight collector
d. Floating-bridge siphon collector
d. Floating-bridge siphon collector
146
In a drying bed, the sand is usually how deep?
a. 1-2 inches (25-50 mm)
b. 2-8 inches (50-200 mm)
c. 4-12 inches (100-300 mm)
d. 10-12 inches (250-300 mm)
c. 4-12 inches (100-300 mm)
147
A(n) _____ is a sedimentation bowl that rotates at high speeds to help separate sludge solids from water by centrifugal force.
a. activator
b. inducer
c. solenoid
d. centrifuge
d. centrifuge
148
What is the cheapest way to transport sludge to lagoons?
Via pipeline
149
What are the primary variables affecting the operation of gravity bed thickeners?
- Polymer dosage and cost
- Thickened solids concentration
- Solids loading and capture
150
Which type of continuous control will maintain control action when signal is lost?
a. Floating proportional control
b. Proportional control
c. Proportional plus reset control
d. Proportional plus reset plus derivative control
a. Floating proportional control
151
Which type of continuous control has a controller constantly tries to change the output if there is deviation from the set point?
a. Proportional plus reset plus derivative control
b. Proportional control
c. Floating proportional control
d. Proportional plus reset control
d. Proportional plus reset control
151
Which type of continuous control requires meters, transmitters, and transducers?
a. Feedback control
b. Feedforward control
c. Floating control
d. Proportional control
a. Feedforward control
152
Which flow measuring device is mechanical?
a. Weir
b. Flume
c. Venturi
d. Loss of head meter
d. Loss of head meter
153
Only a human operator can determine certain elements of plant operations, such as those involving
a. water pressure.
b. water temperature.
c. sight, sound, and smell.
d. chlorine levels
c. sight, sound, and smell.
153
Which of the following is NOT a component of a Bourdon tube pressure gauge?
a. Pointer
b. Pinion gear
c. Bellows
d. Slide
c. Bellows
154
In controlling corrosion, which of the following should be continuously monitored and recorded as water enters the distribution?
a. pH of the water
b. Water color
c. Water temperature
d. Water pressure
a. pH of the water
155
What is usually the most important pressure reading taken in a treatment plant?
Plant discharge pressure
156
What is the simplest form of automation, intended only to turn the chlorinator on and off at the same time as a pressure pump?
Start-Stop control
157
Which device applies an even pressure to the packing such that it compresses tight around the pump shaft?
a. Lantern ring
b. Mechanical seal
c. Packing gland
d. Seal cage
c. Packing gland
158
When using four packing rings, the rings should be staggered at
a. 45 degrees
b. 90 degrees
c. 120 degrees
d. 180 degrees
b. 90 degrees
159
Which type of centrifugal pump impeller is used for pumping medium-sized solids?
a. Open
b. Closed
c. Semi-open
d. Radial
c. Semi-open
160
How is velocity head expressed mathematically?
a. V/g
b. V2/g
c. V2/(2g)
d. V2/32.2 ft/sec2
c. V2/(2g)
161
A pump shaft's main function is to transmit _____ from the motor to the impeller.
a. centrifugal force
b. torque
c. kinetic energy
d. thrust
b. torque
162
A major consideration on starting and stopping large pumps is the prevention of excessive surges and _____ in the distribution system.
a. water hammer
b. turbidity
c. suction loss
d. rust
a. water hammer
163
The head of a double-suction pump can reach
a. 350 ft (100 m).
b. 100 ft (30 m).
c. 1,000 ft (300 m).
d. 500 ft ( 150 m).
a. 350 ft (100 m).
164
What type of pump is designed with the water inlet opening at one end of the pump and the discharge opening placed at a right angle on one side of the casing?
Single-suction pump
165
What device is used when it is not possible to tighten the packing sufficiently to prevent air from entering the pump without casing excessive heat and wear on the packing and shaft, or shaft sleeves?
Lantern ring
166
The primary function of couplings is to transmit the rotary motion of the motor to what component?
Pump shaft
167
Chlorine gas
a. will burn in the presence of oxygen and moisture.
b. will explode in the presence of oxygen and an ignition source.
c. will support combustion.
d. will conduct electricity.
c. will support combustion.
168
Chlorine storage rooms should
a. have sealed walls and doors that open inward.
b. be fitted with chlorine-resistant power exhaust fans ducted out at ceiling level.
c. have lights and fans on the inside and wired to the same switch.
d. have a window in the door so an operator can look into the room to detect any abnormal conditions.
d. have a window in the door so an operator can look into the room to detect any abnormal conditions.
169
Before an authorized entrant enters a permitted confined space,
a. he or she must don SCUBA gear.
b. the internal atmosphere of the space must be tested to measure oxygen content, presence of flammable gasses and vapors, and potentially toxic air contaminants.
c. verify the availability of rescue services.
d. ensure there is adequate lighting in the space to conduct the necessary work.
b. the internal atmosphere of the space must be tested to measure oxygen content, presence of flammable gasses or vapors, and potentially toxic air contaminants.
170
If a substantial chlorine leak incident occurs, which agency should be called for the actual hands-on assistance?
a. The Occupational Safety and Health Administration (OSHA)
b. The Chemical Transportation Emergency Center (ChemTEC)
c. The Transportation Emergency Institute.
d. The Chlorine Institute
b. The Chemical Transportation Emergency Center (ChemTEC)
171
Sites are required to do a site assessment under the Process Safety Management (PSM) regulations (OSHA) if the facility in a single process has more than how many pounds of chlorine?
a. 1,000 lbs
b. 1,500 lbs
c. 2,000 lbs
d. 4,000 lbs
b. 1,500 lbs
172
Which organization issued the Risk Management Rule on July 20, 1996, in an effort to protect public health and safety?
a. AWWA
b. NIOSH
c. OSHA
d. USEPA
d. USEPA
173
Chlorine cylinders must be stored
a. lying on a flat surface.
b. in a temperature-controlled area.
c. with at least 10 ft (1.5 m) of space on all sides.
d. in an area above 160 degrees F (71 degrees C) to ensure chemicals do not settle.
b. in a temperature-controlled area.
174
Which individual in a confined-space operation is responsible for knowing the conditions within the confined space, verifying that all equipment and procedures are in place prior to entry, verifying the availability of rescue services and the means of summoning them, terminating entries and canceling permits, and determining that acceptable conditions as specified in the permit continue for the duration of the entry?
The Entry Supervisor
175
The Department of Homeland Security has partnered with all public and private stakeholders to be better prepared to prevent, detect, respond to, and recover from terrorist attacks and other intentional acts, in addition to natural disasters. What is the term for this effort?
The all-hazards approach.
176
A Material Safety Data Sheet (MSDS) should exist for what type of chemicals?
Every chemical that is used at a water treatment plant
177
What is the rationale for establishing the tree categories of public water systems?
a. Billing purposes
b. Federal funding
c. State and local funding
d. Exposure differences to contaminants
d. Exposure differences to contaminants
178
The American Water Works Association (AWWA) recommends water treatment chemicals be purchased in quantities that maintain a minimum supply at all times for at least
a. 14 days.
b. 15 days.
c. 20 days.
d. 30 days.
d. 30 days.
179
The Partnership for Safe Water suggests that the _____ (and particle count, if available) in each sedimentation basin be recorded periodically (daily, every 4 hours, or hourly).
a. turbidity performance
b. floc count
c. sludge ratio
d. aeration efficiency
a. turbidity performance
180
In general, compliance testing results must be reported no later than _____ after the end of the month in which they were accumulated.
a. 24 hours
b. 1 week
c. 10 days
d. 1 month
c. 10 days
181
Most state regulatory agencies require water plant reporting according to what schedule?
Monthly reports are most often required and immediate notice for Tier 1 violations.
182
After repairing a small chlorine gas leak, what should be your next action?
- Review the situation and determine the cause.
- Establish procedures to prevent reoccurrence.
- Notify utility management so that it can be determined if health authorities should be notified.
183
Filter performance can be determined by reviewing what reports?
- Filter run length
- Turbidity profiles
- Head-loss trends
184
How often must treatment plants record the results of solids retention analysis before and after backwash and the results of sieve analysis of the media?
Every year
185
In communicating with the media, what is the best policy?
- Don't, unless you have to
- Give a brief explanation and offer no more information
186
What are three objectives of responding to customer complaints?
- Address the customer's concern(s)
- Gather information that can be used to identify system problems
- Catalog data that can be used to assess long-term system performance goals
187
What is the water table?
The level of the water surface in an aquifer
188
What are the advantages of a confined aquifer for a water supply?
- Better protected from contamination
- Probably under pressure, so less pumping costs
189
What is a disadvantage of using a confined aquifer for a water supply?
- May be easily depleted
190
Is rain water pure?
No, it main contain pollutants from the air
191
What is the multiple-barrier approach used for at most surface water treatment systems?
A series of treatment steps that are redundant in their ability to remove contaminants
192
What processes are used to remove particles from surface water?
- Coagulation
- Sedimentation
- Filtration
193
Which term refers to the level of the water surface in an aquifer?
a. Runoff
b. Water table
c. Channel flow
d. Watershed
b. Water table
194
What is a key disadvantage of using a confined aquifer for a water supply?
a. It may be easily depleted
b. It is under pressure, making pumping costs excessive
c. It is not protected from contamination
d. It cannot be used in conjunction with other aquifers to supply a well
a. It may be easily depleted
195
Should rainwater be considered pure?
a. No, it may contain pollutants from the air
b. Yes, it is free of pollutants until reaching the ground
c. It depends on the proximity to a major city
d. It depends on weather conditions.
a. No, it may contain pollutants from the air
196
What term refers to a series of treatment steps that are redundant in their ability to remove contaminants?
a. Air stripping
b. Flocculation
c. Ion exchange
d. Multiple-barrier approach
d. Multiple-barrier approach
197
which of the following is NOT a process used to remove particles from surface water?
a. Coagulation
b. Percolation
c. Sedimentation
d. Filtration
b. Percolation
198
Immediately below the water table is the
a. piezometric surface.
b. capillary zone.
c. saturated zone.
d. recharge zone
c. saturated zone.
199
Which type of wells are commonly used near the shore of a lake or near a river?
a. Monitoring wells
b. Bedrock wells
c. Gravel wells
d. Radial wells
d. Radial wells
200
Many streams would dry up after a rain if it were not for
a. human construction influences.
b. surface runoff.
c. capillary action.
d. groundwater flow.
d. groundwater flow.
201
An artesian well could occur in a(n)
a. confined aquifer.
b. unconfined aquifer.
c. water table aquifer.
d. shale formation.
a. confined aquifer.
202
Bored wells, constructed with an auger driven into the earth, are limited in depth to approximately
a. 20 feet
b. 30 feet
c. 50 feet
d. 60 feet
d. 60 feet
203
Because harmful bacteria do not penetrate very far into the soil, wells are generally free of harmful organisms if they are
a. exposed to direct sunlight.
b. more than 50 feet (15 m) deep.
c. connected to multiple aquifers.
d. insulated with limestone.
b. more than 50 feet (15 m) deep.
204
At the surface, all wells should have a sanitary seal, which prevents contamination from entering the
a. well casing.
b. surrounding ground.
c. well slab.
d. submersible pump.
a. well casing.
205
What term refers to the water surface in the well when no water is being taken from the aquifer?
a. Pumping level
b. Drawdown
c. Static water level
d. Water table
c. Static water level
206
Which type of well is commonly used near the shore of a lake or near a river to obtain a large amount of relatively good-quality water from adjacent sand or gravel beds?
a. Radial well
b. Natural well
c. Bedrock well
d. Rotary well
a. Radial well
207
Which of the following is NOT a method by which an aquifer's performance can be evaluated?
a. Drawdown
b. Sequestration
c. Specific-capacity
d. Recovery
b. Sequestration
208
Which type of algae would most likely be found in nutrient-rich waters?
a. Blue-green algae
b. Green algae
c. Diatoms
d. Brown algae
a. Blue-green algae
209
The quantity of dissolved oxygen in water is a function of
a. pH, alkalinity, temperature, and total dissolved solids.
b. temperature and alkalinity.
c. pH and temperature.
d. temperature, pressure, and salinity.
d. temperature, pressure, and salinity.
210
At which temperature does the maximum density of water occur?
a. -4 degrees C (24.8 degrees F)
b. 0.0 degrees C (32 degrees F)
c. 0.4 degrees C (32.72 degrees F)
d. 4.0 degrees C (39.2 degrees F)
d. 4.0 degrees C (39.2 degrees F)
211
Destratification of a lake will often reduce
a. turbidity.
b. nutrients.
c. fish.
d. algae.
d. algae
212
Zebra mussels multiply and spread so fast because
a. the female produces over 250,000 eggs in a single season.
b. the larvae are free swimming for 2 or 3 months before attaching themselves.
c. the commonly adhere to boats, so they move around and disperse eggs.
d. they can live out of water for as long as 3 months.
c. they commonly adhere to boats so they move around and disperse eggs.
213
Which of the following is NOT a principal factor affecting how rapidly surface water runs off the land?
a. Rainfall intensity
b. Soil moisture
c. Vegetative cover
d. The water's pH
d. The water's pH
214
water is drawn into a water supply system from a surface impoundment or stream through
a. a diverted aqueduct.
b. a natural lake.
c. a backwash discharge.
d. an intake structure.
d. an intake structure.
215
A circumstance in which it is more economical or practical to provide treatment at the source, versus in a water treatment facility, is referred to as
a. destratification.
b. recharging.
c. in situ treatment.
d. biological infusion.
c. in situ treatment.
216
Which of the following is NOT a problem commonly associated with algae?
a. Taste and odor
b. Filter clogging
c. Supply shortage
d. Toxicity
c. Supply shortage
217
Division of water into three layers, each of a different temperature, is referred to as
a. salinization.
b. siltation.
c. infiltration.
d. stratification.
d. stratification.
