1. business and industrial
2. energy
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Sample Quiz Questions for A and B
Certification Examination
Florida Rural Water Association
September 2005
Table of Contents
CHLORINATION AND DISINFECTION ................................................................................ 3
DISINFECTION BY-PRODUCTS ........................................................................................... 10
LIME SOFTENING ................................................................................................................... 12
ION EXCHANGE SOFTENING .............................................................................................. 20
REVERSE OSMOSIS ................................................................................................................ 23
WATER STABILIZATION ...................................................................................................... 25
IRON AND MANGANESE REMOVAL ................................................................................. 30
TASTE AND ODOR REMOVAL............................................................................................. 32
FILTRATION ............................................................................................................................. 35
SEDIMENTATION .................................................................................................................... 39
COAGULATION AND FLOCCULATION............................................................................. 41
WATER CHEMISTRY.............................................................................................................. 46
2
Chlorination and Disinfection
1.
The limit of chlorine gas withdrawal for a ton cylinder in a 24 hour period is about
a.
b.
c.
d.
2.
85 % of the cylinder’s volume
40 pounds/day
8 pounds/day per degree fahrenheit
17 % volume/hr. per degree Celsius
In the event of a chlorine leak, the effected area should be diked with what chemicals to
contain and neutralize the chlorine
a.
b.
c.
d.
NaOH, CaO, Ca(OH)2, Na2CO3
NaPO4, NaCL, CaCO3, A12(SO4)3
KMnO4. NaCL, CaCO3, A12(SO4)3
NaCLO2, Ca(P04)2, Ca(OH)2. Na2CO3
3. Hypochlorite is being feed with a hypochlorinator at a set rate of 66gals/day and uses a 7 %
available free chlorine solution. What is the dose at a rate of 2.4 MGD?
a.
b.
c.
d.
1.5 mg/L
11.1 mg/L
1.9 mg/L
3.0 mg/L
Math Applications
Section
4: The disinfecting power of chlorine diminishes when
A:
B:
C:
D:
temperature decreases, OCL ion predominates
temperature increases, OCL ion predominates
temperature increases, HOCL acid predominates
temperature increases. OCL ion and HOCL acid are equal
5 On a gas chlorinator, the Injector vacuum reading is low. Injector water supply is 70 PSI.
What Is the probable cause ?
A:
B:
C:
D;
Insufficient water pressure at the orifice
CPRV (chlorine pressure regulating valve)
injector orifice needs adjustment
flow restricted though the Injector orifice
TROUBLESHOOTING
GUIDE
Section
3
6: Chlorine dioxide reacts with water to form ______
A: CL O2 ions and Cl O3 ions
B: CL O2 and NaCL O2
C: CL- ions and Na ions
D; H Cl ions and NH2Cl
7: Identify the proper fiat of diseases that may be transmitted by water.
A:
B:
C:
D:
encephalitis, amoebic dysentery, common cold, pneumonia
small pox, botulism. spotted fever, enterotoxigenic
chicken pox, giardiasis. whopping cough, measles
giardiasis, typhoid fever, dysentery, hepatitis A
8: The Pressure gauge from the chlorine cylinder reads 90 psi. The gauge on the chlorinator
reads 8 psi. The chlorine residual is dropping. What is the probable cause?
A:
B:
C:
D:
faulty injector (no vacuum)
restriction in supply system
chlorine cylinder is going empty
CPRV is dirty and plugged
TROUBLESHOOTING
GUIDE
9. What is the corrective action to be taken in the previous question?
A: change out orifice
B: adjust injector orifice
C: Clean CPRV with acid
D: Increase water pressure to Injector
TROUBLESHOOTING
GUIDE
10: The Chlorine/ammonia compound with the most effective bactericide power is
A:
B:
C:
D:
dichbromethane
dlchlorlamine
monochloramine
trichloramine
4
11: Calculate the chlorinator setting in pounds of chlorine per 24 hours.
Flow rate: 0.785 MGD
Cl2 demand: 1.95 mg/l
Cl2 residual: 0.30 mg/I.
A:
B:
C:
D:
MATH APPLICATION
SECTION
6.38 lbs
14.5 bs
12.5 lbs
16.3 lbs
12. Select the mg/l of chlorine that it takes to theoretically takes to oxidize 1 mg/l of hydrogen
sulfide to elemental sulfur.
A:
B:
C:
D:
4.00
6.50
2.08
8.32
mg/l.
mg/l.
mg/l.
mg/l
MATH APPLICATION
Section
13. Which one of the following is true with regards to the use of chlorine as a disinfectant ?
A:
B:
C:
D:
14:
chloride ions (Cl- ) increase the disinfection power of Chlorine
sodium hypochlorite will tower the pH of the water
chloramines form when the water contains hydrogen sulfide
chlorine gas will lower the pH of the water
What Is the amount of chlorine required to treat 5 million gallons of water to provide a
0.8 mg/L residual and satisfy a 2.4 mg/l. chlorine demand?
A.
B:
C.
C:
33.0 lbs
66.7 lbs
133.4 lbs
167.7 lbs
MATH APPLICATION
Section
15. The operating vacuum in a ‘gas chlorinator is provided by a hydraulic
injector which utilizes___________ to maintain the vacuum on the system.
A:
B:
C;
D.
a rotameter
a heater
a check valve
water pressure
5
16. At higher chlorine withdrawal rates the chlorine gas is removed from the cylinder faster than
the liquid chlorine is being converted to the gas.
This can lead to:
A:
B:
C:
D:
17.
freezing of the valve
the formation of chlorine dioxide
a leaking lead washer
over feeding of the chlorine
In waters with a high pH, why is free chlorine hard to achieve?
A:
B.
C:
D.
The remaining hydrochloric acid has no disinfecting qualities left
The hypochloric acid disassociates at high pH
The hypochlorous acid disassociates at high pH
none of the above
18. On a gas chlorinator, the injector vacuum reading is low. The injector water supply is 70
psi, the probable cause is?
A:
B:
C:
D:
excessive back pressure al the application point
CPRV (chlorine pressure regulating valve dirty
wrong orifice in the injector
flow restricted through the injector orifice
TROUBLESHOOTING
GUIDE
19. What Is the corrective action to be taken in the question above?
A:
B:
C:
D:
change out orifice
adjust injector orifice
clean the CPRV with acid
decrease water pressure to Injector
MATH APPLICATION
Section
6
20. Pressure in the chlorine header reads 110 lbs. The gauge on the chlorinator reads 5 lbs.
Chlorine residual is dropping. What Is the probable cause?
A:
B:
C:
D:
Injector throat is plugged ( no vacuum)
restriction in water supply system
pig tail on the chlorine cylinder is froze up
CPRV is plugged
TROUBLESHOOTING
GUIDE
Section
21: A liquid chlorine spill can be controlled with?
A:
B:
C:
D:
22:
Ca (OH)2
NaOH
H2O
H2 SO4
TROUBLESHOOTING
GUIDE
Section
A major Limitation of using chloramine residuals is the fact that
chloramines:
A:
B:
C:
D:
are not effective as a disinfectant as free chlorine
form trihalomethanes
increases contact time required
alter the pH of the water
23: The pH of the water being disinfected can alter the efficiency of disinfectants. Chlorine for
example disinfects water (complete the sentence):
A:
B:
C:
D:
24:
much better at a pH of 8.0 than at a pH of 6.0
much faster at a pH of 7.0 than at a pH over 8
the same regardless of pH
much faster at an alkaline pH than at an acidic pH
In establishing a breakpoint curve for a particular water, when chlorine is first added It
Immediately oxidizes iron, manganese, and nitrite. As more chlorine is added, enough to
react with ________ and _________ chlororganics and chloramines are formed.
A:
B:
C:
D:
hydrogen sulfide / sulfur
trihalomethanes / VOC s
chlorine dioxide / sodium chlorite
organics / ammonia
7
25:
Which one of the following is true with regards to the use of chlorine as a disinfectant?
A:
B:
C:
D:
26:
chloride ions (Cl) increase the disinfection power of chlorine
sodium hypochlorite will the lower the pH of the water
chloramines to form when the water contains hydrogen sulfide
chlorine gas will lower the pH of the water
The most effective in-plant destruction of bacteria with chlorine is best accomplished by:
A:
B:
C:
D:
a low concentration ant short contact time
a low concentration and high pH
a low temperature and a high pH
a high concentration and long contact time
27: The following reaction is influenced by the pH of the water being disinfected:
HOCI = H+ + OCl- : The lower the pH, the greater the percentage of —— which will be
present, thus yielding better disinfection action.
A:
B:
C:
D:
H+
OClHOCl
HCl
28. When a chlorinator will feed OK at maximum output, but will not control at low rates, the
most probable cause is:
A:
B:
C:
D:
the vacuum regulator valve is closed or stuck
the flow of water is too low
clogged throat
plugged restrictor
29: A purpose of adding ammonia to potable water is to:
A:
B:
C:
D:
adjust pH
form combined chlorine residual
remove turbidity
protect teeth
30: Carbonate scale may be removed from a hypochlorinator by using:
A:
B:
C:
D:
sulfuric acid
nitric acid
muriatic acid
sodium hydroxide
8
31. Seven pounds of HTH (65% chlorine ) are added to 90 gallons of water and used as a dosing
solution. At the end of the day, only 82 gallons of the solution were used. How many
pounds of chlorine were actually fed?
A:
B:
C:
D:
6.4
8.9
4.2
10.5
MATH APPLICATION
Section
9
Disinfection By-Products
1: Trihalomethane precursors can be defined as:
A:
B:
C:
D:
naturally occurring inorganic compounds
naturally occurring metal cations
naturally occurring oxidizing compounds
naturally occurring organic compounds
2: Samples for THM levels are collected and reported:
A:
B:
C:
D:
weekly
monthly
quarterly
annually
3: Trihalomethanes are formed by the combination of:
A:
B:
C:
D:
free chlorine and Inorganic compounds
free chlorine and natural hydrocarbons
chlorine dioxide and natural tannic acids
all primary disinfectants and natural organics
4: Which one of the following would lead to the least amount of trihalomethane
formation ?
A:
B:
C:
D:
5.
A minimum of how many samples per quarter for THM analysis must be taken
a.
b.
c.
d.
6.
a high concentration of natural organics
a high water temperature
high pH
low pH
2
4
6
number of samples is based on population
What treatment techniques removes THM precursors and bivalent ions?
a.
b.
c.
d.
aeration
ozone treatment
potassium permanganate addition
lime softening
10
7. You have a minor THM problem and decide to add ammonia to the filter effluent. You
are concerned about taste and odor problems. Therefore you should add ammonia at a
ratio, which will produce which compounds?
a.
b.
c.
d.
e.
Monochloromines
Dichloromines
Dichloromines
Chlorophenols
Haloacetic Acids
TROUBLESHOOTING
GUIDE
11
Lime Softening
1.
Minimum hardness that lime soda ash softening can achieve is
a.
b.
c.
d.
Zero
30 to 40 mg/l
80 mg/I
80 to 90 mg/i.
2. The purpose of adding carbon dioxide to softened water ís to:
a.
a.
b.
d.
3.
Lime sludge may be dewatered by
a.
b.
b.
c.
4:
reduce lime usage
Increase finished water pH
restore the methyl alkalinity
restore the carbonate balance
ponds
solar lagoons
solids contact units
sludge collectors
Non-carbonate hardness can only be reduced by which of the following processes?
A:
B:
C:
D:
Ca(OH)2, ion exchange. RO. electrodialysis, NaOH
lime soltening , coagulation, filtration, disinfection
Na2 CO3, ion exchange, membrane separation, NaOH
reverse osmosis, chlorine dioxide, CaO, oxidation
5: Complete the following statement: Selective carbonate removal is
A:
B:
C;
D:
removal of calcium bicarbonate hardness at pH of 9.6
removal of magnesium bicarbonate hardness at pH 10.6
removal of non-carbonate hardness at pH 10.0
removal of calcium sulfate hardness at pH 10.6
12
6:
Using the chemical analyses below, calculate the correct results.
Total Hardness: 180 mg/L
Phenolphthalein Alkalinity: 50 mg/L
A:
B:
C:
D:
Total Alkalinity: 90 mg/l
HCO3: 10 mg/l, CaCO3: 100 mg/l, OH:0, NCH 90 mg/l
HCO3: 100 mg/l, CaCO3 10 mg/l, OH 0 mg/l, NCH 0 mg/l
HCO3: 0 mg/l, CaCO3 80 mg/l, OH 10 mg/l, NCH 90 mg/l
HCO3: 10 mg/l, CaCO3 0 mg/l, OH 80 mg/l, NCH 0 mg/l
MATH
APPLICATION
7: When is noncarbonate hardness is present in water?
A:
B:
C:
D:
when the total hardness is greater than total alkalinity
when the total hardness equals total alkalinity
when the total alkalinity is greater than total hardness
when the total alkalinity is twice the total hardness
8. Select the correct statement.
A:
B:
C:
D:
Ion exchange softening will remove non carbonate hardness
Lime. Softening will increase the calcium content of the water
Lime Softening will reduce the hardness to near zero
Ion exchange softening will reduce the Na content of the treated H20
9: Non-carbonate hardness can be removed by which of the following processes?
A:
B:
C:
D:
Ca(OH)2, ion exchange, oxidation, RO
lime softening. coagulation, filtration, disinfection
Na2CO3, NaOH precipitation, Ion exchange
reverse osmosis, chlorine dioxide, CaO, oxidation
10: Complete the following statement: Selective carbonate, removal is
A:
B;
C:
D:
removal of calcium bicarbonate hardness at pH 9.6
removal of magnesium bicarbonate hardness at pH 10.6
removal of non-carbonate hardness at pH 10.0
removal of calcium sulfate hardness at pH 10.6
13
11. Using the analyses below, calculate the lime dose needed in mg/l as CaO.
Atomic Weights: Ca:40, Mg: 24, H:1, C:12, O: 16, Na:23, F:19
C02: 10 mg/l, Ca:2l8 mg/l, Mg:32 mg/l, TA: 180mg/l, Temp. 78 F
A:
B:
C:
D:
393 mg/l
250 mg/l
189 mg/l
222 mg/l
MATH APPLICATION
Section
12. Using the dosage from the previous question, calculate the lime demand.
Lime 92% pure, flow 3.250 MGD, excess = 7%
A:
B:
C:
D:
6998 pounds of lime
5959 pounds of lime
811 pounds of lime
7881 pounds of lime
MATH APPLICATION
Section
13: Using the following data, calculate the Na2CO3 demand.
Raw Water: Ca: 265 mg/l. Mg: 32mg/l, T ALK:16Omg/l CO2: 12 mg/l
Fin. Water: Ca: 165 mg/l. Mg: 32 mg/I, T ALK: 130 mg/l. C02: 106 mg/l
Flow 865,000 gallons, Na2CO3: 98 % pure
A:
B:
C:
D:
546 pounds of soda ash
5l5 pounds of soda ash
1069 pounds of soda ash
297 pounds of soda ash
MATH APPLICATION
Section
14: When is MgCO3 hardness present in water?
A:
B:
C:
D:
when the total hardness is greater than total alkalinity
when the total hardness equals total alkalinity
when the total alkalinity is greater than total hardness
when the total alkalinity is twice the total hardness
15: Which of the following constituents cause non-carbonate hardness?
A:
B:
C:
D:
CaSO4, CaCO3. MgCL2, NaOH & Sr(HCO3)2
CaSO4. CaCO3, MgCL2. NaOH & MnSiO3
MgSO4, MgCO3, NaCL.2, Ca(OH)2, Fe(HCO3)2
CaSO4, CaCL2, MgCL2, MgSO4, & SrSO4
14
16: Selective Carbonate hardness removal requires the use of:
A:
B:
C:
D:
soda ash
carbon dioxide
lime
lime and soda ash
17. The softening process samples indicate the following data:
T Alkalinity: 90 mg/l. P Alkalinity 40 mg/l.
Treatment parameters call for a treatment range of +2 to +5 hydroxide alkalinity. From
the analysis what action should you take?
A:
B:
C:
D:
decrease Lime feed
increase carbon dioxide feed
decrease carbon dioxide feed
increase lime feed
18: You are operating a lime softening plant where magnesium removal is necessary. The
process includes lime addition, recarbonation and filtration. How could you maintain the
quality of treatment and also save on operating costs?
A:
B:
C:
D:
eliminate recarbonation and use split treatment to lower the pH and save on lime
add calcium carbonate to saturate the softened water
feed lea lime and more soda ash
recarbonate after filtration
19: You are operating a lime softening plant which produces a finished water with a total
hardness of 80 mg/l as Ca CO3, and a Langelier Index of +0.6.
What is the problem?
A:
B:
C:
D:
the finished Water is aggressive
too much CO2 was added
the finished water hardness is too low
the finished water will be scale forming
20: What caused the problem in the question above?
A:
B
C:
D:
the pH was too low
the excessive CO2 increased the L. I.
too much blending
excessive calcium carbonate
15
21:
In spilt treatment, a portion of the water, about ____ is treated
with an excess amount of lime to remove the ____ pH of over ____.
A:
B:
C:
D:
22:
20%; calcium; 7
90%; calcium; 8.3
20%; magnesium; 7
90%; magnesium; 11.1
The determination of total hydroxide alkalinity is an important control test used in the
lime softening process. What is the correct method of determining this number?
A:
B:
C:
D:
T.H.-T. Alk.
2T - P
2 P - T.H.
2P–T
23. Soda ash is commonly used in water treatment to:
A: remove temporary hardness
B: remove all hardness
C: remove permanent hardness
D: lower the pH
24: Calculate the dosage in mg/l hydrated lime Ca(OH)2 required to
soften the water with the characteristics given.
/
Parameter
CO2
Total Alkalinity
Total Hardness
Mg
PH
Lime Purity
A:
B:
C:
D:
188 mg/L
256 mg/L
287 mg/L
174 mg/L
12 mg/ l
202 mg/l
230 mg/l
10 mg/l
7.2
90%
0 mg/l
30 mg/l
50 mg/l
2 mg/l
9.0
MATH APPLICATION
Section
16
25. Calculate the amount of soda ash Na2CO3 required to remove the noncarbonate hardness in
the above problem
A:
B:
C:
D:
30 mg/l
45 mg/l
60 mg/l
125 mg/l
MATH APPLICATION
Section
26: in spit treatment excess lime is added to a portion of the water to remove:
A:
B:
C:
D:
calcium
Iron
magnesium
manganese.
27. What chemical is used to remove non-carbonate hardness in chemical
precipitation softening?
A.
B:
C:
D:
carbon dioxide
calcium sulfate
sodium carbonate
calcium hydroxide
28. Split treatment can eliminate the need for:
A:
B:
C:
D:
lime softening
recarbonation
soda ash
filtration
29. You are using pH to determine lime addition in a lime softening plant. The pH meter
indicates a pH of 10 but after you have added lime you determine that the dose was
excessive. What is the most probable cause?
a.
b.
c.
d.
e.
TROUBLESHOOTING
The water contained an excessive amount of pH
GUIDE
PH was actually 9
The water contained excessive alkalinity
The meter read 10 when it was actually much higher
The lime slaker has malfunctioned
17
30. What will the dosage rate be for a softening plant using 7O% hydrated lime to apply a lime
dosage of 45 mg/l to a flow of 3.2 MGD.
a.
b.
c.
d.
1816 lbs./d
1716 lbs./d
1616 lbs./d
1516 lbs./d
MATH APPLICATION
Section
31. The following are alkalinity titration results and expected conditions:
P = Phenolphthalein Alkalinity
T = Total Alkalinity
O = Not Present
Titration Result
Bicarbonate
P=0
P<½T
P=½T
P>½T
P=T
T
T – 2P
0
0
0
MATH APPLICATION
Section
Carbonate
Hydroxide
0
0
0
2P –T
T
Which is the correct set of data for the Carbonate Conditions?
a.
b.
c.
d.
e.
O, P, 2P, 2T –2P. O
O, 2P, 2P, 2T –2P, O
O, 2P, P, 2T –2P, O
O, 2P, 2P, T –P, O
O, 2P, 2P, 2T –2P, O .
32. When alkalinity (as CaCO3) is greater than the total hardness and the pH is 9.0 you must
____ to soften the water.
a.
b.
c.
d.
e.
Raise the pH to 9.3
Reduce only the Carbonates
Increase the P alkalinity
Precipitate noncarbonate (permanent) hardness
Precipitate Hydroxides
18
33. You have added excess lime to your raw to ensure complete softening reactions, Now you
have scaling problems in the water distribution system and need to convert the carbonate ions
into soluble forms. It would be best for you to:
a. Use Hydrochloric Acid to precipitate calcium carbonate
b. Assure that the following reaction occurs: Mg(HCO3)2 + 2 NaOH >
Mg(OH)2 + 2 Na2CO3 + 2 H2O
c. Lower the pH using recarbonation
d. Add additional lime to increase precipitant in clarifier and force the reactions to
completion
e. Add Soda Ash to decrease non-carbonate scale
34. You have increasingly corrosive water in a lime softening plant. The calcium hardness times
the alkalinity has been near 100 for some time. Now the product is 95. What additional
chemical may be required?
a.
b.
c.
d.
e.
35.
Caustic Soda (Na OH)
Carbon Dioxide
Soda Ash
Potassium Permanganate
Hexametaphosphate
The first step in the softening process is
a
b.
c.
d.
The conversion of carbon dioxide to calcium carbonate
The conversion of magnesium bicarbonate to calcium carbonate.
The conversion of magnesium carbonate to calcium carbonate.
The conversion of calcium bicarbonate to calcium carbonate
36. The minerals that cause hardness in water are precipitated out of the water as
a.
b.
c.
d.
calcium carbonate
magnesium carbonate
calcium carbonate and magnesium carbonate
calcium carbonate and magnesium hydroxide
19
Ion Exchange Softening
1.
Minimum hardness that Ion exchange softening can achieve is
a.
b.
c.
d.
2.
When hard water is softened by ion-exchange, which substance is exchanged for calcium
and magnesium and will appear in the product water
a.
a.
b.
c.
3.
zero hardness
30 to 40 mg/l
80 mg/I.
80 to 90 mg/l
calcium carbonate
sulfates
chloride
sodium
Which of the following. is not affected by passing through a ion-exchange unit.
a.
b.
c.
d.
sodium
manganese ( when present at less than 0.2 mg/l)
magnesium
pH
The following 6 questions are based on the data given below:
Ion exchange softeners:
Exchange capacity:
Salt requirements:
Brine specific gravity:
Flow:
Raw hardness:
Finish hardness:
4 each @ 28.5 ft diameter x 7 ft. media depth
25 kilograms / cubic foot
0.4 lbs/kgr.
1.25
MATH
8, 640,000 gallons per day
513 mg/L
APPLICATION
85 mg/L
4: How many GPM are being softened assuming the daily flow is continuous for 24 hours ?
A: 5006 GPM
B: 994 GPM
C: 6000 GPM
D 36,000 GPM
MATH APPLICATION
Section
20
5: How many kilograms can be removed by all of the softeners ?
6:
A:
B:
111, 583
223, 164
C:
D:
446, 331
62. 643
kgr
kgr
kgr
kgr
MATH APPLICATION
Section
If all the ion exchange units were started at the same time and operated until their exchange
was exhausted, how many gallons would have been softened to near zero hardness?
A: 3,719, 433 gals
B: 2,088,100 gals
C: 7, 438. 800 gals
D: 14, 877, 666 gals
MATH APPLICATION
Section
7. In the question above, how many hours and minutes would have elapsed?
A:
B:
C:
D:
49 hrs. and
41 hrs. and
12 hrs. and
24 hrs. and
32
19
23
46
min
min.
MATH APPLICATION
mm.
min.
Section
8: How many pounds of salt are required to regenerate each softener ?
A:
B:
C:
D:
78, 532
44, 633
25, 057
278, 958
lbs
lbs
lbs
lbs
MATH APPLICATION
Section
9: How many gallons of saturated brine are required for each regeneration?
A:
B:
C:
D:
21, 407
85, 629
11, 989
133. 473
MATH APPLICATION
Section
10. If the finished water from an ion exchange unit has a salty taste, a probable cause for the
problem may be:
A:
B:
C:
D:
too much lime was fed
the rinse stage was unsuccessful
too much zeolite was applied to the media
too much chlorine was present
11. The primary cause of resin breakdown in ion exchange softening is:
A:
B:
C:
D:
oxidation by permanganate
excessive backwashing
iron fouling
the presence of high chlorine residuals
21
12.
The third stage in the ion exchange process is
a.
b.
c.
d.
service
backwash
brine
rinse
13. In Ion exchange softening, if Iron in the ferric form is found in the water
what will occur in the softening unit?
A:
B:
C:
D:
the resin will remove the Iron
the unit act as a filter
nothing will change
the unit will automatically shutdown
14. In Ion exchange softening a high chlorine residual will:
A:
B:
C:
D:
have no effect
regenerate the resin
damage the resin
short circuit the unit
22
Reverse Osmosis
1.
The cause of lower than normal product water flow rates and higher than normal salt
rejection in an R0 plant is
a.
b.
c.
d.
2.
TROUBLESHOOTING
GUIDE
The solution to the problem in question 117 is
a.
b.
c.
d.
3.
membrane hydrolysis
membrane fouling
membrane compaction
membrane failure
replace element
clean element
colloidal injection
all of the above
TROUBLESHOOTING
GUIDE SECTION
Reverse Osmosis increasing the flux rate
a.
b.
c.
d.
will cause an increase in salt concentration
will not affect the salt concentration
will reduce the salt concentration
will cause salt build up and polarization
4. Constituents affecting the RO include all but which of the following:
a.
b.
c.
d.
e.
pH
Temperature
Suspended Solids
Microbrial Concentration
Conductivity
5. Fouling in RO systems is typically caused by:
a.
b
c.
d.
e.
Backwash Frequency
Service on Membranes
High Water Pressure
Bacteria
Concentration of Calcium in Rinse Water
23
6. Polarization in an RO system is caused by:
a.
b
c.
d.
e.
Fouling caused by high hardness
Fouling of the Anode or Cathode
Brine or Regeneration concentration that is too high
Mineral Deposits along the edge of a membrane
Plugging of Membrane inner surfaces
7. Reverse Osmosis Systems
a.
b.
c.
d.
do not require pretreatment to remove colloidal material.
are designed to remove minerals and colloidal material
require pretreatment to remove colloidal material
can remove colloidal material only if coagulants are added to reject
8. RO systems are best operated with all units
1.
2.
3.
4.
9.
in series to gain maximum removal rates
in parallel to gain maximum throughput
staggered with gradually decreasing number of modules
staggered with gradually increasing number of modules
The reserve osmosis elements should be cleaned when the operator observes
a.
b.
c.
d.
e.
Higher differential pressures
Higher operating pressures
Higher suspended solids in product water
Lower product water flow rate
Lower salt rejection
10. If a salty taste is noted in an RO process what is the most probable cause:
a.
b
c.
d.
e.
Polarization is occurring
Service rate us too low
Brine or Regeneration Rate should be increased
Recycle Stream is too high
Rinse Rate should be increased
24
Water Stabilization
1.
Removal of hydrogen sulfide from water with a pH of 9.4 can be accomplished by
a.
b.
c.
d.
2.
Corrosion resulting from contact between two dissimilar metals is called
a.
b.
c.
d.
3.
tuberculation corrosion
erosion corrosion
pitting corrosion
galvanic corrosion
Turbulence tends to increase which type of corrosion
a.
b.
c.
d.
6.
tuberculation corrosion
erosion corrosion
pitting corrosion
galvanic corrosion
Chlorides tend to increase which type of corrosion
a.
b.
c.
d.
5.
tuberculation corrosion
erosion corrosion
pitting corrosion
galvanic corrosion
Corrosion that forms mounds of iron oxide next to the anode is called
d.
e.
c.
d.
4.
increasing coagulant chemicals
lowering the PH
increasing aeration and lowering pH
increasing aeration
tuberculation corrosion
erosion corrosion
pitting corrosion
galvanic corrosion
Black water complaints may be caused by
a.
b.
c.
d.
corrosion of copper lines
corrosion of ductile iron pipes
sulfide corrosion of iron lines
microbial activity
TROUBLESHOOTING
GUIDE
(SEE TABLE)
25
7.
The primary source of household plumbing problems is
a.
b.
c.
d.
8.
tuberculation corrosion
erosion corrosion
pitting corrosion
galvanic corrosion
TROUBLESHOOTING
GUIDE SECTION
If a pH of a finished water is 8.0 and has high levels of carbon dioxide and dissolved
oxygen, the water is
a.
b.
c.
d.
noncorrosive
corrosive
scale forming
saturated
9: In order for Ca CO3 film to form, one of the following conditions must be
met.
A:
B:
C:
D
no HCO3 ions must be present
pH values must be In excess of 10
the water must be undersaturated with OH Ions
The. Langlier Index must be zero
10: Identify the correct reaction that will form a calcium carbonate film.
A:
B:
C:
D:
11.
Ca2+ + HCO3 + OH > CaCO3 + H20
Ca2+ + CaCO3 + OH> HCO3 + H2O
CaCO3 + CO3 + H2O > Ca2 + 2 HCO3
2 HC03 + CO3 + H20 > Ca2 + CaC03
Which one of the following is not one of the indices that can be used to determine
calcium carbonate saturation of a water?
A:
B;
C;
D:
driving force index
Langelier index
Rossum index
aggressive index
TROUBLESHOOTING
GUIDE SECTION
26
12:
From the results of the MARBLE TESTS below, which sample would be corrosive to a
water system over a long period of time?
Sample
pH
Alk.
Hardness
1
1
before CaCO3 8.3
after CaCO3 8.3
84
84
117
117
2
2
before CsCO3 8.3
After CaCO3 8.1
90
88
118
115
3
before CaCO3 7.8
After CaCO3 8.2
88
94
140
148
4
4
before CaCO3 7.9
after CaCO3 8.0
90
89
138
133
A:
B:
C:
D
sample 1
sample 2
sample 3
sample 4
TROUBLESHOOTING
GUIDE SECTION
13: positive Langlier Index is an indicator that the water is
A:
B:
C:
D:
corrosive
scale forming
stable
equilibrium
TROUBLESHOOTING
GUIDE SECTION
14: The metabolic process that consumes oxygen and releases carbon dioxide is called?
A:
B:
C:
D
E.
respiration
photosynthesis
eutrophication
sterilization
hydrolosis
15: Low pH and the absence of oxygen in a section of the distribution system may result in
A:
B:
C:
D:
the formation of phenol-misted odors
The de-zincification of ductile pipe
formation of hydrogen sulfide
conditions ideal for the growth of aerobic bacteria
27
16. A Langlier Index 0 or a Driving Force Index of 1 indicates the water is
A;
B:
C:
D:
supersaturated
saturated
undersaturated
corrosive
TROUBLESHOOTING
GUIDE SECTION
17. The parameters necessary to calculate the Driving Force Index are?
A:
B:
C:
D:
temperature, CaCO3, pH, Oxygen, K’ sp for CaCO3
temperature, pH, Mg, Free CO2, total alkalinity
temperature, pH, Salinity, Hardness, CO32-, mg/l as CaCO3
temperature, TDS, Ca hardness, CO32-, mg/l as CaCO3, K’ sp for CaCO3
18. Electrolysis is the result of ______.
A;
B:
C:
D:
19:
20:
From the following water analysis, which corrosion control chemicals would be best to
select?
Ca2+
hardness: 40 mg/L
A
B:
C:
D:
line or sodium carbonate
lime or caustic soda
lime and carbon dioxide
caustic soda or soda ash
Total Alkalinity: 11 mg/L
TDS: 137
When a galvanic cell occurs as a result of two dissimilar metals. It is important to know
that corrosion will always occur at the:
A:
B:
C:
D:
21:
a corrosive oxygen cell
a corrosive galvanic cell
breakdown of Cathodic protection
stray electric current
neutral electrode
cathode
potentiometric surface
anode
_______ Inhibits corrosion by forming a film on the interior of water pipes.
A:
B:
C:
D
turbercules
DO
calcium carbonate
salinity
28
22: Scaling is a problem in hot water systems because _____ is less
soluble in hot water than In cold water.
A:
B:
C:
D:
23:
Iron
dissolved oxygen
chlorine
calcium carbonate
Test results indicate a pHs value of 8.7 and a pH value of 8.8 for treated water. What
does this mean?
A:
B:
C:
D:
24:
the water is corrosive
the Langleir index is between -0.2 and .0.2
the pH should be increased to 9.5
the water is undersaturated with calcium
In selecting corrosion control chemicals, If the product from multiplying the calcium
hardness by the alkalinity is 80, this indicates that:
A:
B:
C:
D:
either lime or soda ash would be satisfactory
both lime and carbon dioxide may be required
soda ash will be ruled out because of expense
the water is stable and requires no calcium
25. gram of calcium carbonate is added to a filtered water sample giving the following results;
determine the calcium carbonate precipitation potential.
Initial pH =
Final pH =
Initial Hardness =
Final Hardness =
Initial Alkalinity =
Final Alkalinity =
8.7
9.1
34 mg/l
38 mg/l
24 mg/l
27 mg/l.
a. 0.4
b. –3
c. –4
d. 3
e. 4
29
Iron and Manganese Removal
1.
The mineral other than iron, that may occur in low concentrations and causes staining
problems on laundry is
a.
b.
c.
d.
2.
ferric
magnesium
rust
manganese
The most effective PH range for iron removal
a.
b.
c.
d.
6 or less
7 to 8
8 to 9
9 or higher
3. In the greensand process, what chemical is necessary for the process to be
effective?
A:
B:
C:
D:
chlorine
lime
potassium permanganate
sodium carbonate
4: When using aeration, the rate of oxidation of Iron to form Insoluble ferric can be increased by:
A:
B:
C:
D:
decreassing the temperature
raising the pH of the water
decreasing the detention time
lowering the pH of the water
5: Chemical doses being added to control Iron and /or manganese are inadequate if:
A:
B:
C:
D:
analysis of treated water shows the presence of Iron
there is incomplete conversion of ferric iron to ionic iron
customers complain of rusty water
all of the above
30
6: Which one of the following is not a chemical oxidant which could be used to control taste and
odor in water supplies?
A:
B:
C:
D:
chlorine
chlorine dioxide
ozone
sulfur
31
Taste and Odor Removal
1.
The first warning the supplier has of possible contaminants from a
cross connection are complaints of taste and odors of:
A:
B:
C
D;
2:
Aeration normally does not provide enough oxidant to attack:
A:
B:
C:
D:
3:
one pound per gallon of Water
one pound per pound of water
one pound per 100 pounds of water
one pound per million pounds of water
Which of the following dosages is considered to be a typical or average load rate for
control of TOC with potassium permanganate?
A:
B:
C
D:
5:
the taste and odor producing organics
organic compounds which are relatively volatile
reduce forms of ferrous Iron and manganous manganese
The reduced inorganic compounds
Powdered activated carbon slurry tanks are normally loaded at a rate of:
A:
B:
C:
D:
4:
septic or musty
chemical, gasoline, or pesticide
rotten egg or sulfur
fishy or swampy
0.10
1.0
0.30
1.3
to
to
to
to
0.50 mg/l
3.0 mg/l
0.50 mg/l
1.7 mg/l
You have a taste and odor problem which requires you to superchlorinate the water going
through your p1ant. How would you dechlorinate this water prior to distributing it?
A.
B.
C:
D:
use calcium carbonate
use hydrogen sulfide
GAC or PAC
use thiosulfate
32
6. What treatment process would best treat a water containing 250 mg/l of hardness, 100 CU’s of
color and a turbidity of 2 NTU’s.
a.
b.
c.
d.
Conventional lime softening
Ion exchange
RO
Chlorination and filtration only
TROUBLESHOOTING
GUIDE SECTION
7. Which treatment process would best treat a water containing 80 mg/l of hardness, 1.0 CU’s of
color and a turbidity of .2 NTU’s.
a.
b.
c.
d.
8.
Conventional lime softening
Ion exchange
RO
Chlorination and filtration only
TROUBLESHOOTING
GUIDE SECTION
Which treatment process would best treat a water containing 350 mg/l of hardness, 10
CU’s of color, 30 mg/I of total organic carbon and a turbidity of 2 NTU’s.
a.
b.
c.
d.
Conventional lime softening
Ion exchange
RO
Chlorination and filtration only
TROUBLESHOOTING
GUIDE SECTION
9. Which treatment process would best treat a water containing 250 mg/l of hardness, 10 CU’s of
color and a turbidity of 2 NTU’s. The plant’s only customer requires a finished water
containing zero hardness.
a.
b.
c.
d.
10.
Conventional lime softening
Ion exchange
RO
Chlorination and filtration only
TROUBLESHOOTING
GUIDE SECTION
Which treatment process would best treat a water containing 350 mg/l of hardness, 10
CU’s of color, 3 mg/l of total organic carbon and a turbidity of 2 NTU ‘s.
a.
b.
c.
d.
Conventional lime softening
Ion exchange
RO
Chlorination and filtration only
TROUBLESHOOTING
GUIDE SECTION
33
Problem: Marshy, or woody odor. Use this to answer questions 11. 12, and 13.
11.
a.
b.
c.
12.
increase in organisms in water supply
increase in Actinomycetes in water supply
bacteria and/or algae increase
Required check
a.
b.
c.
d.
13.
TROUBLESHOOTING
GUIDE SECTION
Possible cause
check for nitrates
check for coliform
check for organisms
check for algae
TROUBLESHOOTING
GUIDE SECTION
Possible solution
a.
b.
c.
d.
increase chlorination
add activated carbon
apply algaecide
apply potassium permanganate
TROUBLESHOOTING
GUIDE SECTION
34
Filtration
1.
Persistent filter blinding may be overcome by
a.
b.
c.
d.
2.
changing media
changing or adjusting coagulant
improving backwash
using filter aids
Mud ball formation in a filter bed may be caused by
a.
b.
c.
d.
3.
TROUBLESHOOTING
GUIDE SECTION
more greensand
ion resin
potassium permanganate
sand
As a plant supervisor, two of our most important concerns are:
a.
b.
c.
d.
e.
5.
low surface scour rates
improper coagulation
sludge removal rates
rapid mix speed
Greensand is regenerated with
b.
c.
d.
e.
4.
TROUBLESHOOTING
GUIDE SECTION
Chemical and pathogen free drinking water
Clean and inexpensive drinking water
To provide consumers with drinking water of suitable quality and sufficient
quantity
Employee harmony and efficiency
Safe working conditions and pure water.
If you had to choose a single, easily run test which would give the best indication
Of water quality, you would choose which test?
a.
b.
c.
d.
e.
Hydrogen sulfide
Turbidity
THM
TDS
Color
35
6.
What should you do if test results indicate a filter mud ball volume of 2.6%
a.
b.
c.
d.
e.
Nothing, this is good
Add a polymer
Reduce the coagulant dose
“Bump” the filter gravel
Extend the backwash duration.
TROUBLESHOOTING
GUIDE SECTION
7. The design head loss in your filter is 10 feet. Your loss of head is 8 feet, the turbidity is
0.4 NTUs and the elapsed run time is 24 hours. It would be best to:
a.
b.
c.
d.
“Bump” the filter to delay backwashing
TROUBLESHOOTING
Slow the flow to the filter
GUIDE SECTION
Backwash the filter first thing next morning
Increase the polymer dose
8. When a filter wash is uneven, the spots violently over washed might result in which of the following?
a.
Damage to sludge removal equipment
a. Cause the sand grains in this area to cement together.
TROUBLESHOOTING
b. Cause an increase in the sand effective size.
GUIDE SECTION
c. Overturn the gravel layer, allowing sand to displace it.
9. When cold water starts to warm up, a condition that can occur in the media of a filter is called
a. Mudballing
b. Jet action
TROUBLESHOOTING
c. Bed shrinking
GUIDE SECTION
d. Air binding
10. Air binding of a filter can be caused by
a. The reduction of pressure resulting from operating under a negative head
a. An increase in the temperature of the water during filtration
b. The release of oxygen by algae collected within the filter
TROUBLESHOOTING
c. All of the above
GUIDE SECTION
11. Some idea of the amount of filter media growth can be indicated by
a. Periodic sieve analysis of the media
b. Periodic measurements of the distance from the top of the clean filter to the trough weir
c. Periodic determinations of the percent solubility of the media in hydrochloric acid
d. All of the above
TROUBLESHOOTING
GUIDE SECTION
36
12. Three items are missing in the information provided, Which one of the sets of data below
are the correct entries for the missing information for both filters?
Filter Operating Record
No,
1
2
Time
Start
Stop
6/15
8:30
6/12
6/18
11:30
6/18
Hours Operated
Today Previous Total
Head Loss
Start
Stop
Wash
Min
M. Gal
11:30
63.7
75.0
0.50
6.00
6
0.14
18:00
82.0
100.0
0.50
5.50
5
0.14
Average Run Hours =
_________
Total Wash Water (MG) = _________
Ave. Time of Wash =
_________
e.
f.
g.
h.
i.
13.
87.5 hrs; 0.28 MG and 5.5 min.
72.65 hrs, 0.28 MG and 6 min.
72.65 hrs, 0.28 MG and 5.5 min.
75 hrs, 0.14 MG and 5 min
100 hrs, 0.14 MG and 5.5 min
Mixed media filters
a.
b.
c.
d.
Use anthracite coal over sand
May require a secondary coagulant applied ahead of the filters.
Sometimes uses pressure to achieve higher filtration rates.
All of the above
37
14. All but one of the choices below are disadvantages of Aeration. Which is the most
important advantage?
Aeration can:
a.
b.
c.
d.
e.
Lead to bacterial contamination
Remove THMs after they have been formed
Remove volatile organic compounds
Perform as a reducing agent
Perform best a low pH.
15. Your plant has a source water of consistent quality and the plant has a good performance
record. Lately the filter turbidity removal efficiency has decreased. What is the most urgent
check to perform?
a.
b.
c.
d.
Raw water quality
Condition of flocculation basin
Coagulant dosage
Color content of water
38
Sedimentation
1.
Sedimentation is improved by
a.
b.
c.
d.
2.
A lime sludge collection device should
a.
b.
c.
d.
3.
reducing detention time
short circuiting
installing tube settlers
all of the above
move very slowly
move rapidly to collect as much sludge as possible
be turned on at regular intervals for a short time
be turned on only when enough sludge is available to warrant use
Preventive maintenance on an upflow clarifier includes
a.
b.
c.
d.
leveling a weir to correct short circuits
rebuilding the drive unit motor
replacing scraper blades
cleaning walkways
4. You operate a surface water plant that uses an up-flow clarifier, has a raw water pH of 7.4
and an alkalinity of 260 mg/l. Each spring as the weather changes, you have a severe taste
and odor problem. What change might you consider for the clarifier to minimize this
problem?
a.
b.
c.
d.
e.
5.
Add additional coagulant and polymer
Increase the amount of activated carbon in the slurry
Change the through-put rate to the Clarifier
Increase the sludge blanket depth
TROUBLESHOOTING
Increase the amount of prechlorination
GUIDE SECTION
In and up-flow clarifier, when you want to increase the depth of the slurry, without
increasing its volume or density, what would you do?
a.
b.
c.
d.
e.
Increase the rising rate
Raise the weirs
Slowly decrease the flow rate to the Clarifier
Rapidly increase the flow rate to the Clarifier
Rapidly increase the overflow rate
TROUBLESHOOTING
GUIDE SECTION
39
6. It is in the middle of the summer and you are having a breakdown in the coagulation
process in our up-flow clarifier due to algae, this problem occurs only in the late
afternoon, with periods of good operation before and after this problem period. What
changes should you make during the problem periods to improve the finished water
quality?
a.
b.
c.
d.
e.
Allow the Sludge blanket to build
Increase the amount of activated carbon in the slurry
Increase the slurry level
Increase the sludge blanket depth
TROUBLESHOOTING
Reduce the sludge blanket depth
GUIDE SECTION
40
Coagulation and Flocculation
1.
Pin point floc is a condition associated with
a.
b.
c.
d.
2.
Operators are concerned primarily with particles in water that usually carry a
a.
b.
c.
d.
3.
negative electrical charge
positive electrical charge
both positive and electrical charge
charge depends on location of plant
The main purpose of flocculation is to
a.
b.
c.
d.
4.
flash mixing
detention time
poor filtration
low turbidity
allow chemicals to mix thoroughly
produce floc
bring together micro floc
improve settling
An inspection of your Coagulation/Flocculation filtration plant yielded the following
problems. Match the corrective action for each condition cited.
Observed Conditions (match with number below)
1.
2.
3.
4.
Floc as it enters the basin is large and sheared
Water has a milky appearance with a bluish tint
Floc size increases in the flocculation basin then starts to break up.
Floc rapidly settles in the first part of the sedimentation basin.
Corrective Actions
a.
b.
c.
d.
a.
b.
c.
d.
d,b,a,c
a.c.d.b
c.d.a.b
d,c,a,b
Mixing intensity of the downstream flocculator is too high
Excessive Coagulant dosage
Excessive alum dosage
Flash mixer is set too high
TROUBLESHOOTING
GUIDE SECTION
41
5. Your feed rate scale for Flocculation chemicals is in pre-set (with a range of 100%) and
is set at a maximum feed rate of 15%. You have determined that the best feed rate for the
Flocculator is 3 GPH. What should the feeder be set on?
a.
b.
c.
d.
e.
5%
12%
20%
30%
45%
MATH APPLICATION
SECTION
6. You suspect a problem with your chemical feeder. From the following data, determine
the proper chemical feed rate.
Starting Level of container pumped from
Level of chemical after pumping
Feed Time
a.
b.
c.
d.
e.
1.25 ml/min
26.7 ml/min
200 ml/min
260.7 ml/min
1600 ml/min
= 1000 ml
= 800 ml
= 30 sec.
MATH APPLICATION
SECTION
7. The inorganic compounds (i.e. iron) are effectively removed from your raw water using
aeration. Tests indicate an increasing taste and odor problem due to volatile organic
compounds. Which action below would be best for these circumstances?
a.
b.
c.
d.
e.
Reduce the aeration rate
Increase detention period to allow more organics to burn off
Increase blower pressure
Add a reducing agent
Add an oxidizing agent
42
8. A random listing of procedures used to start up a coagulation flocculation process is
listed below. Place the procedure in the proper order.
1.
2.
3.
4.
5.
6.
7.
8.
a.
b.
c.
d.
e.
Start chemical feed system
Run a jar test on the raw water
Turn flash mixer on
Start sampling pumps
Open raw water inlet gate
Check condition of all mechanical equipment
Begin disinfection
Observe floc formation
5, 2, 1, 7, 3, 4, 8, 6
6, 2, 5, 1, 7, 3, 4, 8
5, 6, 2, 1, 7, 3, 4, 8
6, 5, 1, 2, 7, 3, 4, 8
6, 2, 5, 1, 4, 7, 3, 8
9. You have adverse changes in the raw water temperature. It would be best to adjust the
flash mixer but this is not possible in your plant. Which action below would be the most
appropriate?
a.
b.
c.
d.
e.
Reduce the amount of coagulant chemical
Increase the amount of coagulant chemical
Increase the pH with soda ash
Add an ionic filter aid chemical polymer
Adjust the mixing intensity of the flocculator
TROUBLESHOOTING
GUIDE SECTION
10. You have observed that the floc as it enters the flocculation basin is not well dispersed
throughout the flow. What is the most likely problem?
a.
b.
c.
d.
e.
No problem, it will ix as it gets to the sedimentation basin
Flash mixer too slow
Coagulant dose too high
TROUBLESHOOTING
Feed rate too high
GUIDE SECTION
Polymer addition needs to be increased
43
11. You are considering the addition of alum to your up-flow clarifier. You determine that 12
mg/l of alum is correct. The raw pH is 8.0 and the alkalinity is 230 mg/l. You know that
it takes an excess of 21 mg/l of alkalinity per mg/l of alum for precipitation to occur.
What would be the best selection in this situation?
a.
b.
c.
d.
e.
Go ahead and slowly start adding the Alum
Add additional alum to increase the alkalinity
Add lime or soda ash to increase the alkalinity
Add carbon dioxide to decrease the alkalinity
Adjust the mixing intensity of the flocculator
12. You use alum as a coagulant. Here would it be best to take a sample of the water for a jar
test in order to set a target pH?
a.
b.
c.
d.
e.
Between the flocculation and the sedimentation basin
Before chlorination of the finished water
Just past the raw water inlet gate
After the flash mixer
In the mixing zone of the sediment basin
13. You raw water alkalinity increased from 230 mg/l to 235 mg/l and the pH to 7.9. Your
chlorine residual then dropped below acceptable limits. What is the most likely cause of
this condition?
TROUBLESHOOTING
a. Excess alkalinity reacted with the chlorine
GUIDE SECTION
b. Chlorine has been converted to hypochlorous acid
c. Chlorine has reacted with mineral compounds that raised the pH
d. There has been an increase in hypochlorite
14.
Alum usually
a.
b.
c.
d.
15.
has an optimum PH of 5.5 to 6.8
is effective on highly colored waters at pH’s below 5.5
effective with high mineral waters at PH as high as 7.5
all of the above
Sodium Aluminate
a.
b.
c.
d.
TROUBLESHOOTING
GUIDE SECTION
TROUBLESHOOTING
GUIDE SECTION
acidic
very corrosive
reduces both carbonate and noncarbonate hardness
all of the above
44
16.
Proper coagulation results in
a.
b.
c.
d.
17.
reduction in turbidity
pH adjustment
increase in filter runs
all of the above
The optimum pH range for ferric sulfate usage is
a.
b.
c.
d.
3.5 to 5.5 and above 9
below 4.2 and above 8.2
above 8.3
above 9.6
18. Sodium Aluminate is
a.
b.
c.
e.
19.
TROUBLESHOOTING
GUIDE SECTION
The influent into the plant has a high color and a turbidity of .05 NTU. What can be done
to improve coagulation.
a.
b.
c.
d.
20.
Alkaline
Acidic
not expensive
has a pH of 7
add alum
add lime
add Bentonite clay
A or B and C
TROUBLESHOOTING
GUIDE SECTION
Polymers are:
a.
b.
c.
d.
coagulants
coagulant aids
used for removing color
corrosive inhibitors
45
Water Chemistry
1.
Which of the following is not a correct statement for the specific conductance test?
a.
b.
c.
d.
e.
2.
pH is a measure of the
a.
b.
c.
d.
3.
carbonate and bicarbonate ions
carbonate ions
bicarbonate ions
sulfates
Alkalinity can also be called
a.
b.
c.
d.
6.
alkalinity
calcium
bicarbonate ions
sulfates
Carbonate hardness is caused by
a.
b.
c.
d.
5.
amount of acid
strength of an acid
acidity
alkalinity
Noncarbonate hardness is caused by
a.
c.
c.
d.
4.
Specific conductance is measured in microhmos per centimeter
Specific conductance is the water’s ability to conduct current
Organic matter such as sucrose will increase the specific conductance
Specific conductance can be used to estimate dissolved solids concentrations in the
water
Specific conductance is affected by temperature
carbonate hardness
noncarbonate hardness
phenolophthalein alkalinity
methyl alkalinity
Alkalinity is expressed as
a.
b.
c.
d.
mg/l phenolophthalein alkalinity
mg/l of methyl alkalinity
mg/l of calcium carbonate
total alkalinity
46
7.
A shorthand name for a chemical element is
a.
b.
c.
d.
8.
Organisms that can make their own food from strictly inorganic matter are called
a.
b.
c.
d.
9.
confirm that safety guards are in place
examine all fittings and drains for leaks
flush out solution lines
inspect all equipment for binding and rubbing
Free chlorine residual refers to
a.
b.
c.
d.
12.
aerobic organisms
plants
algae
facultative organism.
When shutting down a fluoride system operators should
a.
b.
c.
d.
11.
autotrophic
parasitic
heterotrophic
aerobic
Oxygen bound up in such compounds as sulfates and nitrates may serve as Oxygen
sources for
a.
d.
c.
d.
10.
chemical compound
chemical formula
scientific notation
chemical symbol
dichloramirie
hypochlorination
trichloramine
total chlorine
Which chemical is used to oxidize iron and manganese
a.
b.
c.
d.
alum
monochloramine
calcium oxide
potassium permanganate
47
13.
Health authorities encourage use of reclaimed water for
a.
b.
c.
d.
14.
Which of the following affect the efficiency of copper sulfate
a.
b.
c.
d.
15.
check for toxic conditions
check for dissolved oxygen
check for algae
check or organics
Possible solution
a.
b.
c.
d.
17.
dissolved oxygen
organic carbon
iron
temperature
Possible Checks
a.
b.
c.
d.
16.
drinking water supply
municipal swimming pools
deep well injection
landscape impoundment’s
ensure adequate chlorination
increase calcium oxide dose
apply ferric chloride
apply copper sulfate
You are conducting a pH test with a meter which does not have a slope knob. You must
use the temperature knob to reach pH 10. Which action should you take?
a.
b.
c.
d.
e.
Add more pH to buffer solution
Allow more time for the CO2 to doissapate
Replace the electrodes
Allow more time for the temperature to stabilize
Change the buffer solution to a pH 10 to 11.
48
18.
Flow recorders
a.
b.
c.
d.
19.
Samples taken for PH measurement should be
a.
b.
c.
d.
20.
correcting process operational problems
correcting equipment operational problems
identifying problems, causes, and solutions
preventing process problems
Oxygen transfer rate is dependent on
a.
b.
c.
d.
23.
less chance of error
probe and meter need little preparation
allow measurements to be made directly in the stream
all of the above
Troubleshooting is a technique for
a.
b.
c.
d.
22.
refrigerated
tested within one hour
allowed to warm to room temperature
measured for temperature
Advantages of using a dissolved oxygen probe and meter include.
a.
b.
c.
d.
21.
record the rate of flow at a given time
record the total flow through the plant
function similar to an odometer
record raw water flow
size of air bubbles
size of aerator motor
total area of liquid exposed to air
rate of flow
Hypochlorite tends to
a.
b.
c.
d.
Increase pH
Decrease pH
have no effect on PH
decrease alkalinity
49
24.
A well water has a pH of 6.2, alkalinity 540, total hardness 320, calcium hardness 120,
turbidity 5, color 300, TDS 100, TOC 35. Which treatment process should be used
a.
b.
c.
d.
e.
f.
25.
When using a pH meter the deterioration in the electrode must be corrected by
a.
b.
c.
d.
26.
pressure gauge
hydrometer
rotameter
manometer
Which of the following statements is true regarding ground water movement
a.
b.
c.
d.
29.
amperometric titration
color comparison
DPD
orthotolidine
A glass tube partially filled with liquid that measures gas pressure is called a
a.
b.
c.
d.
28.
adjusting the temp control
slope control adjustment
storing the electrode in pH buffer 7
all of the above
The chlorine residual method that is the standard for regulatory purposes is
a.
b.
c.
d.
27.
disinfection/filtration
lime—soda ash
conventional lime softening
Ion exchange
R0
Electrodialysis
Preésure differences between the areas of recharge and discharge have little effect
on rate of flow.
The zone of capillary fringe increases the flow by draining water into the aquifer.
Ground water moves continually, even though the movement may be slow.
Seasonal variations have little effect on the slope of the water table.
The negative electrode where reduction occurs is called
a.
b.
c.
d.
anion
anode
cathode
cation
50
30.
A utility that serves a population of 25001 to 28000 must pick up the following number
of coliform samples per month
a.
b.
c.
d.
31.
An example of a cation is
a.
b.
c.
d.
32.
increase alkalinity
remove noncarbonate hardness
remove carbon dioxide
remove carbonate hardness
Coagulants normally used in water treatment release
a.
b.
c.
d.
34.
chloride
sulfate
bicarbonate
sodium
The principal reason for using soda ash is to
a.
b.
c.
d.
33.
20
40
50
60
negatively charged ions.
ions having more than one positive charge
multivalent negative Ions
monovalent positive ions
Nonsettlable solids are classified into 3 categories
a.
b.
c.
d.
suspended, colloidal, dissolved
colloidal, dissolved, total dissolved
coarse, fine, very fine
colloidal, suspended. settleable
51
35.
Zeta potential is not
a.
b.
c.
e.
36.
Packing glands on most centrifugal pumps should be
a.
b.
c.
d.
37.
pH
total solids
dissolved solids
suspended solids
Water with a dissolved solids concentration of 1500 ppm
may be classified as
a.
b.
c.
d.
40.
fluoride
nitrate
calcium carbonate
bicarbonate
Specific conductance is an Indirect measure of
a.
b.
c.
d.
39.
not allowed to leak
allowed to leak slightly
allowed to leak 5.5 MGD
allowed to leak .10 GPM
The anion usually found in highest concentrations in natural waters is
a.
b.
c.
d.
38.
an electrical charge between particles
an attracting force between particles
a repelling force between particles
a force opposite the van der wald force
slightly saline
moderately saline
very saline
brine
Which of the following Inorganic substances exceeds the MCL
a.
b.
c.
d.
arsenic 0.01 mg/l
nitrate 15.00 mg/l
barium 0.07 mg/l
silver 0.05 mg/l
52
41.
When coliform occurs in 3 of the 5 ten ml portions of a single standard sample
a.
b.
c.
d.
daily samples must be collected until two consecutive
satisfactory samples are obtained
the water main must be chlorinated
public notification is required
all of the above
53