AWWA Water Operator Certification
Exam Prep
What is the most common disinfection by product when adding chlorine to water
containing natural and inorganic matter? - Answer-Chloroform
/.What will most probably cause taste and odors, slime, and filter clogging? - Answer-
Blue-green Algae
/.Why can rapid sand filters handle higher filtration rates compared to slow sand filters?
- Answer-Coarser sand
/.Iron bacteria can interfere with ___________ because the bacteria produce
_____________that prevents the stabilization chemicals from reaching the pipe surface.
- Answer-stabilization, a slime layer
/.Hypochlorous acid is favored over hypochlorite ion when the pH is _____________and
the temperature is ___________. - Answer-low, low
/.What filter has an unstratified media distribution? - Answer-slow sand filters
/.What is (are) the combine chlorine residual(s) at pH values ranging from 6.5 to 8.5? -
Answer-Monochloramine and dichloramine
/.When iron alone is treated using manganese greensand filters, the chlorine feed rate
should be about _________________. - Answer-1.0 to 1.2 times the iron concentration
/.chlorination of water that has high concentrations of natural organic matter will produce
- Answer-THMs
/.When disinfecting with chloramines, when can the ammonia be added to the process?
- Answer-Before, same time as, or after the chlorine
/.What will settle out of the water in a short period of time? - Answer-Very fine silt
/.Point-of-use activated carbon filters are most effective for removing
_________________. - Answer-Chlorine
/.Potassium permanganate is used as an oxidant for control of
____________________. - Answer-Iron and manganese, organic precursors, and taste
and odors
,/.What must an operator periodically check regarding the cyclone separator system? -
Answer-Storage bin or hopper to empty of sand and grit
/.These types of chemicals chemically tie up scale-forming ions and are eventually
ingested by consumers. - Answer-Sequestering agents
/.An operator should record filter ______________ measurements, condition, and depth
of media on a ________ basis. - Answer-bed expansion, quarterly
/.Lime will precipitate noncarbonate hardness from the water, but it also orms
noncarbonate salts that cause noncarbonate hardness. What are these salts? - Answer-
CaSO4 and CaCl2
/.What are absolute ratings based on with regard to membranes? - Answer-Largest pore
opening
/.How ar manganese greensand beds regenerated? - Answer-Backwashed with
permanganate solution
/.The most effective process for removing radon gas, when considering cost and
footprint, would be ____________. - Answer-packed tower aeration
/.What is the primary advantage of placing a properly sized anthracite coal layer over
manganese greensand? - Answer-Longer filter run times
/.What factor will cause problems for chlorination? - Answer-Foreign substances
/.In the lime-soda ash softening process, smaller plants find that ________ is less
expensive to purchase; regardless of the size of the plant, ___________ needs to be
mixed long enough because it dissolves rather slowly. - Answer-calcium hydroxide, lime
/.What does the optimal pH establish when applied to iron and manganese oxidation? -
Answer-Detention time
/.A water plant using chloramines as a disinfectant has allowed sizable amounts of
turbidity to enter the distribution system. If this occurs over a period of years, what will
occur at the far end of the distribution system? - Answer-Taste and odor will develop,
Bacterial growth will be supported, and Nitrification
/.The reduction of color would most likely occur after - Answer-coagulation, flocculation,
and sedimentation
/.To eliminate hydrogen sulfide (H2S), the pH of the water should be lowered to
____________ or less before beginning aeration. - Answer-6.0
/.Permanganate reactions are largely dependent on ___________. - Answer-pH
,/.What are the primary reasons that more small water stems are installing pressure
filters? - Answer-Because installation and operating costs are low
/.Because lime slurries have a _________ and a ___________ in water, calcium
carbonate will ____________ on anything the slurry touches. - Answer-high pH, low
solubility, preciptate
/.It is recommended that the free chlorine residual at a customer's tap should be at least
________. - Answer-0.2 mg/L
/.Microfiltration is considered to be intermediate between ___________ based on pore
size. - Answer-ultrafiltration and multimedia granular filtration
/.After microscreening, there should be a significant reduction in ______________. -
Answer-Turbidity
/.How can the problem of poorly formed floc be solved? - Answer-Use of coagulant aid
/.What chemical used in corrosion control gives off large quantities of CO2 when it
comes in contact with an acid? - Answer-Soda ash
/.Alum requires _____________ to be present naturally or added fro proper coagulation,
and about _____________ is required for each milligram of alum added per liter. -
Answer-alkalinity, 0.5 mg/L
/.A cloudy appearance in the last flocculation chamber is usually caused by
____________. - Answer-inadequate coagulant dosage
/.What type of meter is most commonly use for customer metering? - Answer-Positive-
displacement meters
/.In general, the size of floc that has been found to be optimal for settling efficiency is
____________________. - Answer-pinhead-size floc
/.In a pulsator clarifier, what is the purpose of the pulses and how often are pulses
generated? - Answer-To maintain a uniform sludge layer; 40-50 sec
/.UV application will - Answer-inhibit bacterial growth and replication
/.Calcium hypochlorite used in water treatment disinfection ranges in percentage
strength of available chlorine from _______________. - Answer-65% to 70%
/.Manganese greensand filters remove iron and manganese by a combination of both
_________. - Answer-Adsorption and oxidation
, /.After water has been softened, it is close to pH 11; thus, it needs to be stabilized by a
process known as recarbonation. What small amount of hardness chemical is formed
and what is precipitated in the process? - Answer-Calcium bicarbonate, magnesium
carbonate
/.UV is used as a disinfectant because it is effective in the inactivation of _____ and
because it _______. - Answer-Cryptosporidium, does not produce DBPs
/.A common problem with hypochlorinators is ____________. - Answer-broken
diaphragm
/.If algae or slime growth in sedimentation basins are a problem, drain the basin and
apply a solution of _______ per liter of water using a brush to remove the growth. -
Answer-10g of copper sulfate and 10 g of lime
/.What two major problems will improperly stabilized softened water cause? - Answer-
scale deposits or corrosive water
/.Coagulation and flocculation are _____ processes. - Answer-Chemical and
mechanical
/.The C x T value is calculated using most or part of the treatment plant, some
distribution piping and to the _______. - Answer-first customer
/.The most important reason to control corrosion and scaling in the distribution system is
to _______. - Answer-protect public health
/.A bacterial slime layer prevents the deposition of _____, and when the slime
occasionally gets sloughed away, the slime carries away _______ and leaves the pipe
surface bare. - Answer-calcium carbonate, calcium carbonate
/.What is the major advantage of GAC over anthracite? - Answer-Better adsorption of
organics
/.The success of the conventional treatment design is primarily due to the ___________
process. - Answer-Coagulation, sedimentation, filtration (All of the above)
/.How is hardness expressed in the ion exchange process? - Answer-grains/gal
/.Manganese will produce _______ water. - Answer-brown or black
/.Air binding is caused by pressure in the filters __________ than atmospheric pressure,
and it can cause _______ flow. - Answer-lower, resistance to
/.What filter types would be best for direct filtration? - Answer-monomedium filters
Exam Prep
What is the most common disinfection by product when adding chlorine to water
containing natural and inorganic matter? - Answer-Chloroform
/.What will most probably cause taste and odors, slime, and filter clogging? - Answer-
Blue-green Algae
/.Why can rapid sand filters handle higher filtration rates compared to slow sand filters?
- Answer-Coarser sand
/.Iron bacteria can interfere with ___________ because the bacteria produce
_____________that prevents the stabilization chemicals from reaching the pipe surface.
- Answer-stabilization, a slime layer
/.Hypochlorous acid is favored over hypochlorite ion when the pH is _____________and
the temperature is ___________. - Answer-low, low
/.What filter has an unstratified media distribution? - Answer-slow sand filters
/.What is (are) the combine chlorine residual(s) at pH values ranging from 6.5 to 8.5? -
Answer-Monochloramine and dichloramine
/.When iron alone is treated using manganese greensand filters, the chlorine feed rate
should be about _________________. - Answer-1.0 to 1.2 times the iron concentration
/.chlorination of water that has high concentrations of natural organic matter will produce
- Answer-THMs
/.When disinfecting with chloramines, when can the ammonia be added to the process?
- Answer-Before, same time as, or after the chlorine
/.What will settle out of the water in a short period of time? - Answer-Very fine silt
/.Point-of-use activated carbon filters are most effective for removing
_________________. - Answer-Chlorine
/.Potassium permanganate is used as an oxidant for control of
____________________. - Answer-Iron and manganese, organic precursors, and taste
and odors
,/.What must an operator periodically check regarding the cyclone separator system? -
Answer-Storage bin or hopper to empty of sand and grit
/.These types of chemicals chemically tie up scale-forming ions and are eventually
ingested by consumers. - Answer-Sequestering agents
/.An operator should record filter ______________ measurements, condition, and depth
of media on a ________ basis. - Answer-bed expansion, quarterly
/.Lime will precipitate noncarbonate hardness from the water, but it also orms
noncarbonate salts that cause noncarbonate hardness. What are these salts? - Answer-
CaSO4 and CaCl2
/.What are absolute ratings based on with regard to membranes? - Answer-Largest pore
opening
/.How ar manganese greensand beds regenerated? - Answer-Backwashed with
permanganate solution
/.The most effective process for removing radon gas, when considering cost and
footprint, would be ____________. - Answer-packed tower aeration
/.What is the primary advantage of placing a properly sized anthracite coal layer over
manganese greensand? - Answer-Longer filter run times
/.What factor will cause problems for chlorination? - Answer-Foreign substances
/.In the lime-soda ash softening process, smaller plants find that ________ is less
expensive to purchase; regardless of the size of the plant, ___________ needs to be
mixed long enough because it dissolves rather slowly. - Answer-calcium hydroxide, lime
/.What does the optimal pH establish when applied to iron and manganese oxidation? -
Answer-Detention time
/.A water plant using chloramines as a disinfectant has allowed sizable amounts of
turbidity to enter the distribution system. If this occurs over a period of years, what will
occur at the far end of the distribution system? - Answer-Taste and odor will develop,
Bacterial growth will be supported, and Nitrification
/.The reduction of color would most likely occur after - Answer-coagulation, flocculation,
and sedimentation
/.To eliminate hydrogen sulfide (H2S), the pH of the water should be lowered to
____________ or less before beginning aeration. - Answer-6.0
/.Permanganate reactions are largely dependent on ___________. - Answer-pH
,/.What are the primary reasons that more small water stems are installing pressure
filters? - Answer-Because installation and operating costs are low
/.Because lime slurries have a _________ and a ___________ in water, calcium
carbonate will ____________ on anything the slurry touches. - Answer-high pH, low
solubility, preciptate
/.It is recommended that the free chlorine residual at a customer's tap should be at least
________. - Answer-0.2 mg/L
/.Microfiltration is considered to be intermediate between ___________ based on pore
size. - Answer-ultrafiltration and multimedia granular filtration
/.After microscreening, there should be a significant reduction in ______________. -
Answer-Turbidity
/.How can the problem of poorly formed floc be solved? - Answer-Use of coagulant aid
/.What chemical used in corrosion control gives off large quantities of CO2 when it
comes in contact with an acid? - Answer-Soda ash
/.Alum requires _____________ to be present naturally or added fro proper coagulation,
and about _____________ is required for each milligram of alum added per liter. -
Answer-alkalinity, 0.5 mg/L
/.A cloudy appearance in the last flocculation chamber is usually caused by
____________. - Answer-inadequate coagulant dosage
/.What type of meter is most commonly use for customer metering? - Answer-Positive-
displacement meters
/.In general, the size of floc that has been found to be optimal for settling efficiency is
____________________. - Answer-pinhead-size floc
/.In a pulsator clarifier, what is the purpose of the pulses and how often are pulses
generated? - Answer-To maintain a uniform sludge layer; 40-50 sec
/.UV application will - Answer-inhibit bacterial growth and replication
/.Calcium hypochlorite used in water treatment disinfection ranges in percentage
strength of available chlorine from _______________. - Answer-65% to 70%
/.Manganese greensand filters remove iron and manganese by a combination of both
_________. - Answer-Adsorption and oxidation
, /.After water has been softened, it is close to pH 11; thus, it needs to be stabilized by a
process known as recarbonation. What small amount of hardness chemical is formed
and what is precipitated in the process? - Answer-Calcium bicarbonate, magnesium
carbonate
/.UV is used as a disinfectant because it is effective in the inactivation of _____ and
because it _______. - Answer-Cryptosporidium, does not produce DBPs
/.A common problem with hypochlorinators is ____________. - Answer-broken
diaphragm
/.If algae or slime growth in sedimentation basins are a problem, drain the basin and
apply a solution of _______ per liter of water using a brush to remove the growth. -
Answer-10g of copper sulfate and 10 g of lime
/.What two major problems will improperly stabilized softened water cause? - Answer-
scale deposits or corrosive water
/.Coagulation and flocculation are _____ processes. - Answer-Chemical and
mechanical
/.The C x T value is calculated using most or part of the treatment plant, some
distribution piping and to the _______. - Answer-first customer
/.The most important reason to control corrosion and scaling in the distribution system is
to _______. - Answer-protect public health
/.A bacterial slime layer prevents the deposition of _____, and when the slime
occasionally gets sloughed away, the slime carries away _______ and leaves the pipe
surface bare. - Answer-calcium carbonate, calcium carbonate
/.What is the major advantage of GAC over anthracite? - Answer-Better adsorption of
organics
/.The success of the conventional treatment design is primarily due to the ___________
process. - Answer-Coagulation, sedimentation, filtration (All of the above)
/.How is hardness expressed in the ion exchange process? - Answer-grains/gal
/.Manganese will produce _______ water. - Answer-brown or black
/.Air binding is caused by pressure in the filters __________ than atmospheric pressure,
and it can cause _______ flow. - Answer-lower, resistance to
/.What filter types would be best for direct filtration? - Answer-monomedium filters
