Wastewater Treatment Operator Certification
Test #2 – Exam Questions and 100% Verified
Solutions
What impact does temperature have on the reaction rate of microorganisms in
wastewater?
A) Reaction rate doubles with every 18 degree Fahrenheit increase in temperature
until higher temperature inhibits biological activity
B) Reaction rate decreases by 20% with every 10 degree Fahrenheit increase in
temperature
C) Reaction rate of microorganism is not impacted by temperature
D) Reaction rate goes to zero - ANSWER -A) Reaction rate doubles with every 18
degree Fahrenheit increase in temperature until higher
What is commonly used to control the odor of hydrogen sulfide?
A) Carbon Dioxide
B) Methane
C) Chlorine
D) Hydrogen - ANSWER -C) Chlorine (v.1 pg 398)
What is used to determine the amount of microorganisms in the aeration tank?
A) Mixed Liquor Suspended Solids (MLSS)
B) Influent TSS
C) BOD
D) Mixed Liquor Volatile Suspended Solids (MLVSS) - ANSWER -D) Mixed
Liquor Volatile Suspended Solids (MLVSS) (v.2 pg 58)
What could happen if the sludge line is isolated by closing the valves on each end
for several days?
A) It could result in water hammer
B) Cavitation
C) Gas production could increase the internal pressure and cause the line to fail
,D) The aerobic condition will cause Zoolgleal mass to grow in large numbers. -
ANSWER -C) Gas production could increase the internal pressure and cause the
line to fail (v.2 pg 152)
Which is true about chlorine gas?
A) It is 2.5 times lighter than air
B) it is 2.5 times heavier than air
C) It is 1.5 times heavier than air
D) It is 1.5 times lighter than air - ANSWER -B) it is 2.5 times heavier than air (v.1
pg 375)
Which of the following is typically treated by biological processes?
A) Roots and rags
B) Sand and eggshells
C) Cinders
D) Dissolved and non settable organic material - ANSWER -D) Dissolved and non
settable organic material (v.1 pg 46)
Which document is a written record that accurately traces the custody of
wastewater samples through all phases of a monitoring program?
A) Wastewater Lab Analysis form
B) NEPA
C) Chain of Custody form
D) Diagnostic form - ANSWER -C) Chain of Custody form (v.2 pg 498)
What could cause a sudden drop in pH of the influent?
A) Acidic chemical in the influent
B) A strong base was dumped into the collection system
C) Ammonia from a factory was discharged into the sewer
D) The influent contained sodium hydroxide - ANSWER -A) Acidic chemical in
the influent (v.2 pg 579)
What is the recommended daily maintenance activity for a clarifier?
A) Dewater the clarifier by draining the wastewater
B) Repaint metal surfaces that have lost their protective coating
, C) Hose down walls, floor and equipment inside the clarifiers
D) Inspect chains, sprockets, and flights. - ANSWER -D) Inspect chains, sprockets,
and flights (v.1 pg 118)
Which of the following could be the cause of ponding in a trickling filter?
A) Hydraulic loading is too low
B) Clogging of distributor orifices
C) Excessive organic loading
D) Denitrification - ANSWER -C) Excessive organic loading (v.1 pg 192)
What could happen if the dissolved oxygen content in the aeration tank is too low?
A) Pinpoint floc will develop
B) Filamentous organisms could thrive and prevent the sludge sludge floc from
settling properly in the secondary clarifier
C) Settling will improve in the secondary clarifier
D) Sludge bulking will be eliminated - ANSWER -B) Filamentous organisms
could thrive and prevent the sludge sludge floc from settling properly in the
secondary clarifier (v.1 pg 254)
What is the expected BOD removal efficiency in a facultative pond?
A) Mostly between 40 to 50%
B) Mostly between 30 to 40%
C) Mostly between 20 to 30%
D) Mostly between 70 to 80% - ANSWER -D) Mostly between 70 to 80% (v.1 pg
317)
What is a chloramine?
A) Free chlorine
B) A chemical that is formed when chlorine reacts with iron
C) Combined chlorine- a chemical that is formed when chlorine reacts with
ammonia
D) A chemical that is formed when chlorine reacts with air. - ANSWER -C)
Combined chlorine- a chemical that is formed when chlorine reacts with ammonia
(v.1 pg 350)
What is sludge bulking in an activated sludge process?
Test #2 – Exam Questions and 100% Verified
Solutions
What impact does temperature have on the reaction rate of microorganisms in
wastewater?
A) Reaction rate doubles with every 18 degree Fahrenheit increase in temperature
until higher temperature inhibits biological activity
B) Reaction rate decreases by 20% with every 10 degree Fahrenheit increase in
temperature
C) Reaction rate of microorganism is not impacted by temperature
D) Reaction rate goes to zero - ANSWER -A) Reaction rate doubles with every 18
degree Fahrenheit increase in temperature until higher
What is commonly used to control the odor of hydrogen sulfide?
A) Carbon Dioxide
B) Methane
C) Chlorine
D) Hydrogen - ANSWER -C) Chlorine (v.1 pg 398)
What is used to determine the amount of microorganisms in the aeration tank?
A) Mixed Liquor Suspended Solids (MLSS)
B) Influent TSS
C) BOD
D) Mixed Liquor Volatile Suspended Solids (MLVSS) - ANSWER -D) Mixed
Liquor Volatile Suspended Solids (MLVSS) (v.2 pg 58)
What could happen if the sludge line is isolated by closing the valves on each end
for several days?
A) It could result in water hammer
B) Cavitation
C) Gas production could increase the internal pressure and cause the line to fail
,D) The aerobic condition will cause Zoolgleal mass to grow in large numbers. -
ANSWER -C) Gas production could increase the internal pressure and cause the
line to fail (v.2 pg 152)
Which is true about chlorine gas?
A) It is 2.5 times lighter than air
B) it is 2.5 times heavier than air
C) It is 1.5 times heavier than air
D) It is 1.5 times lighter than air - ANSWER -B) it is 2.5 times heavier than air (v.1
pg 375)
Which of the following is typically treated by biological processes?
A) Roots and rags
B) Sand and eggshells
C) Cinders
D) Dissolved and non settable organic material - ANSWER -D) Dissolved and non
settable organic material (v.1 pg 46)
Which document is a written record that accurately traces the custody of
wastewater samples through all phases of a monitoring program?
A) Wastewater Lab Analysis form
B) NEPA
C) Chain of Custody form
D) Diagnostic form - ANSWER -C) Chain of Custody form (v.2 pg 498)
What could cause a sudden drop in pH of the influent?
A) Acidic chemical in the influent
B) A strong base was dumped into the collection system
C) Ammonia from a factory was discharged into the sewer
D) The influent contained sodium hydroxide - ANSWER -A) Acidic chemical in
the influent (v.2 pg 579)
What is the recommended daily maintenance activity for a clarifier?
A) Dewater the clarifier by draining the wastewater
B) Repaint metal surfaces that have lost their protective coating
, C) Hose down walls, floor and equipment inside the clarifiers
D) Inspect chains, sprockets, and flights. - ANSWER -D) Inspect chains, sprockets,
and flights (v.1 pg 118)
Which of the following could be the cause of ponding in a trickling filter?
A) Hydraulic loading is too low
B) Clogging of distributor orifices
C) Excessive organic loading
D) Denitrification - ANSWER -C) Excessive organic loading (v.1 pg 192)
What could happen if the dissolved oxygen content in the aeration tank is too low?
A) Pinpoint floc will develop
B) Filamentous organisms could thrive and prevent the sludge sludge floc from
settling properly in the secondary clarifier
C) Settling will improve in the secondary clarifier
D) Sludge bulking will be eliminated - ANSWER -B) Filamentous organisms
could thrive and prevent the sludge sludge floc from settling properly in the
secondary clarifier (v.1 pg 254)
What is the expected BOD removal efficiency in a facultative pond?
A) Mostly between 40 to 50%
B) Mostly between 30 to 40%
C) Mostly between 20 to 30%
D) Mostly between 70 to 80% - ANSWER -D) Mostly between 70 to 80% (v.1 pg
317)
What is a chloramine?
A) Free chlorine
B) A chemical that is formed when chlorine reacts with iron
C) Combined chlorine- a chemical that is formed when chlorine reacts with
ammonia
D) A chemical that is formed when chlorine reacts with air. - ANSWER -C)
Combined chlorine- a chemical that is formed when chlorine reacts with ammonia
(v.1 pg 350)
What is sludge bulking in an activated sludge process?
