Wastewater Treatment Operator Certification
Test #2 – Exam Questions and 100% Verified
Solutions
What is the carbon dioxide content of a properly functioning anaerobic digester?
A) 65 to 70% by volume
B) 1 to 2% by volume
C) 30 to 35% by volume
D) 40 to 60% by volume - ANSWER -C) 30 to 35% by volume (v.2 pg 158)
Which of the following is a collection of individual samples obtained at regular
intervals?
A) Grab
B) Culmination
C) Comprehensive
D) Composite - ANSWER -D) Composite (v.2 pg 499)
What is the most common piece of laboratory equipment, which is used mainly to
mix chemicals and measure approximate volumes?
A) Beaker
B) Graduated cylinder
C) Pipet
D) Flask - ANSWER -A) Beaker(v.2 pg 479)
What are colloids?
A) Solids that settle rapidly
B) Dissolved solids
C) Solids found in the grit channel
D) Very small, finely divided solids that remain dispersed in a liquid for a long
time - ANSWER -D) Very small, finely divided solids that remain dispersed in a
liquid for a long time (v.1 pg 22,144)
What is the most common type of grit collector?
,A) Deflectors
B) Weirs
C) Chain driven scrapers called "flights"
D) Parshall flume - ANSWER -C) Chain driven scrapers called "flights" (v.1 pg
87)
What is true about surface loading and detention time?
A) They stay fairly constant throughout the day
B) They are impacted by the influent BOD
C) They are indirectly related to flow
D) They are directly related to flow - ANSWER -D) They are directly related to
flow (v.1 pg 118)
What is the slime growth on a trickling filter called?
A) Filamentous bacteria
B) Zoogleal film
C) Stalked ciliate
D) Acid formers - ANSWER -B) Zoogleal film (v.1 pg 169)
What should be done if you observe a small, steady stream of water leakage from
the pump packings?
A) tighten the packings until they are water tight
B) Replace the packing
C) Do nothing. The leakage is required to cool and lubricate the dynamic surface
D) Replace the pump - ANSWER -C) Do nothing. The leakage is required to cool
and lubricate the dynamic surface (v.2 pg 344)
What should be done if the SVI is high and there is an excess of normal
filamentous microorganisms in the activated sludge process?
A) Inject hydrogen peroxide in the secondary effluent
B) Make sure DO levels is very low in the aeration tank
C) Decrease MLSS and sludge age
D) Chlorinate the return activated sludge - ANSWER -D) Chlorinate the return
activated sludge (v.2 pg 60)
When is confined space considered oxygen deficient?
, A) In atmosphere where oxygen content is less than 19.5% by volume
B) In atmosphere where oxygen content is less than 23.5% by volume
C) In atmosphere where oxygen content is less more than 23.5% by volume
D) In atmosphere where oxygen content is less than 29.5% by volume - ANSWER
-A) In atmosphere where oxygen content is less than 19.5% by volume (v.2 pg
267)
Which of the following is not true about chlorine gas?
A) 2.5 times heavier than air
B) Extremely toxic
C) Common chlorine gas concentration at the treatment plants is 12.5%
D) Corrosive in moist atmosphere - ANSWER -C) Common chlorine gas
concentration at the treatment plants is 12.5% (v.1 pg 375)
What is a "dead spot" in an activated sludge process?
A) An area in the secondary clarifier with rising sludge
B) An area in the aeration tank that has insufficient mixing
C) An area in the aeration tank that has high concentration of DO
D) An area in the secondary clarifier with may dead viruses - ANSWER -B) An
area in the aeration tank that has insufficient mixing
Which of the following is an improper way to control an anaerobic digester?
A) Control the loading rate or food supply
B) Control the volatile acid/alkalinity relationship
C) Control mixing
D) Control the acid formation so that it is larger than the methane formation -
ANSWER -D) Control the acid formation so that it is larger than the methane
formation (v.2 pg 148)
Which of the following is not true about permitted confined space entry?
A) Wear an approved harness with an attached line
B) If the entry is made through a top opening, use a hoisting device with a harness
that suspends a person in an upright position
C) Testing for atmospheric hazards is not required as long as a blower is in use
Test #2 – Exam Questions and 100% Verified
Solutions
What is the carbon dioxide content of a properly functioning anaerobic digester?
A) 65 to 70% by volume
B) 1 to 2% by volume
C) 30 to 35% by volume
D) 40 to 60% by volume - ANSWER -C) 30 to 35% by volume (v.2 pg 158)
Which of the following is a collection of individual samples obtained at regular
intervals?
A) Grab
B) Culmination
C) Comprehensive
D) Composite - ANSWER -D) Composite (v.2 pg 499)
What is the most common piece of laboratory equipment, which is used mainly to
mix chemicals and measure approximate volumes?
A) Beaker
B) Graduated cylinder
C) Pipet
D) Flask - ANSWER -A) Beaker(v.2 pg 479)
What are colloids?
A) Solids that settle rapidly
B) Dissolved solids
C) Solids found in the grit channel
D) Very small, finely divided solids that remain dispersed in a liquid for a long
time - ANSWER -D) Very small, finely divided solids that remain dispersed in a
liquid for a long time (v.1 pg 22,144)
What is the most common type of grit collector?
,A) Deflectors
B) Weirs
C) Chain driven scrapers called "flights"
D) Parshall flume - ANSWER -C) Chain driven scrapers called "flights" (v.1 pg
87)
What is true about surface loading and detention time?
A) They stay fairly constant throughout the day
B) They are impacted by the influent BOD
C) They are indirectly related to flow
D) They are directly related to flow - ANSWER -D) They are directly related to
flow (v.1 pg 118)
What is the slime growth on a trickling filter called?
A) Filamentous bacteria
B) Zoogleal film
C) Stalked ciliate
D) Acid formers - ANSWER -B) Zoogleal film (v.1 pg 169)
What should be done if you observe a small, steady stream of water leakage from
the pump packings?
A) tighten the packings until they are water tight
B) Replace the packing
C) Do nothing. The leakage is required to cool and lubricate the dynamic surface
D) Replace the pump - ANSWER -C) Do nothing. The leakage is required to cool
and lubricate the dynamic surface (v.2 pg 344)
What should be done if the SVI is high and there is an excess of normal
filamentous microorganisms in the activated sludge process?
A) Inject hydrogen peroxide in the secondary effluent
B) Make sure DO levels is very low in the aeration tank
C) Decrease MLSS and sludge age
D) Chlorinate the return activated sludge - ANSWER -D) Chlorinate the return
activated sludge (v.2 pg 60)
When is confined space considered oxygen deficient?
, A) In atmosphere where oxygen content is less than 19.5% by volume
B) In atmosphere where oxygen content is less than 23.5% by volume
C) In atmosphere where oxygen content is less more than 23.5% by volume
D) In atmosphere where oxygen content is less than 29.5% by volume - ANSWER
-A) In atmosphere where oxygen content is less than 19.5% by volume (v.2 pg
267)
Which of the following is not true about chlorine gas?
A) 2.5 times heavier than air
B) Extremely toxic
C) Common chlorine gas concentration at the treatment plants is 12.5%
D) Corrosive in moist atmosphere - ANSWER -C) Common chlorine gas
concentration at the treatment plants is 12.5% (v.1 pg 375)
What is a "dead spot" in an activated sludge process?
A) An area in the secondary clarifier with rising sludge
B) An area in the aeration tank that has insufficient mixing
C) An area in the aeration tank that has high concentration of DO
D) An area in the secondary clarifier with may dead viruses - ANSWER -B) An
area in the aeration tank that has insufficient mixing
Which of the following is an improper way to control an anaerobic digester?
A) Control the loading rate or food supply
B) Control the volatile acid/alkalinity relationship
C) Control mixing
D) Control the acid formation so that it is larger than the methane formation -
ANSWER -D) Control the acid formation so that it is larger than the methane
formation (v.2 pg 148)
Which of the following is not true about permitted confined space entry?
A) Wear an approved harness with an attached line
B) If the entry is made through a top opening, use a hoisting device with a harness
that suspends a person in an upright position
C) Testing for atmospheric hazards is not required as long as a blower is in use
