1|Page
Colorado Wastewater Treatment Operator Class A
Exam ACTUAL VERIFIED EXAM COMPLETE
QUESTIONS AND CORRECT ANSWERS LATEST
UPDATE.pdf
If fine-bubble diffusers are used to introduce air into a
biological reactor, the surface of the tank will typically have
what type of appearance? - Answer-Mildly agitated,
partially covered with light foam
In an anoxic activated sludge process, oxygen for
facultative bacteria is provided by...? - Answer-Nitrate,
NO3
A small area of dark gray/black sludge in an aeration tank
can be due to aeration equipment failure or ____. -
Answer-The introduction of a septic sidestream
When doing a 30-minute activated sludge settleability test,
a 1000ml Imhoff cone should be used. - Answer-FALSE
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In a conventional activated sludge process, how much
oxygen is required per lb. of BOD removed? - Answer-0.8
to 1.2 lb oxygen /lb BOD
Which of the following conditions would least likely
contribute to rising sludge in secondary clarifiers? -
Answer-Clarifier hydraulic loading
In an activated sludge process bacteria release chemicals
called ________ that break down the food particles that
are adsorbed to the cell wall so that they can be absorbed
by the microorganism. - Answer-Enzymes
Acids should never be added to chlorine solutions
because they - Answer-Cause chlorine gas to be released
Chloramines are ____? - Answer-Combined chlorine
What are the characteristics for chlorine as used in
pollution control? - Answer-Chlorine gas is toxic, corrosive,
and heavier than air
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Chlorine applied minus ____ equals chlorine residual -
Answer-Chlorine demand
Unlike chlorine, UV does not leave what in treated water?
- Answer-A residual
Coliform bacteria are: - Answer-Indicators
A _____ residual is attained after breakpoint chlorination. -
Answer-Free
If you need a chlorine residual of 1 mg/l, how many
pounds of chlorine must be applied each day if the flow is
2.5 mgd and the chlorine demand is 15 mg/l? - Answer-
334 lb/d
A total residual is also referred to as a ______ residual. -
Answer-Combined
Total and fecal coliform are pathogenic. - Answer-FALSE
, 4|Page
_________ = flow, mgd x chlorine dosage, mg/L x 8.34
lb/gal. - Answer-Feed Rate/Dose (lbs/day)
Sodium hypochlorite is manufactured by the reaction of
gaseous or liquid chlorine with a solution of _________
_________ to produce a liquid containing NaOCl. -
Answer-Sodium hypochlorite
At concentrations less than _____, chlorine gas is not
detectable by the human sense of smell. - Answer-1 ppm
A treatment plant uses sulfur dioxide to dechlorinate
effluent. An operator needs to adjust the sulfonator so that
the dosing concentration is 1.5 mg/l more than the chlorine
residual. Based on the following information, what should
the sulfonator feed rate be: design flow = 5 mgd; chlorine
dosage rate = 4 mg/l; chlorine residual = 0.9 mg/l -
Answer-100 lb/day
The UV dose represents the product of the rate of energy
emission (lamp intensity) and the time the organisms are
exposed to the germicidal energy at 254 nm. This can be
expressed by the equation: - Answer-Dose = intensity x
time (d=It)
Colorado Wastewater Treatment Operator Class A
Exam ACTUAL VERIFIED EXAM COMPLETE
QUESTIONS AND CORRECT ANSWERS LATEST
UPDATE.pdf
If fine-bubble diffusers are used to introduce air into a
biological reactor, the surface of the tank will typically have
what type of appearance? - Answer-Mildly agitated,
partially covered with light foam
In an anoxic activated sludge process, oxygen for
facultative bacteria is provided by...? - Answer-Nitrate,
NO3
A small area of dark gray/black sludge in an aeration tank
can be due to aeration equipment failure or ____. -
Answer-The introduction of a septic sidestream
When doing a 30-minute activated sludge settleability test,
a 1000ml Imhoff cone should be used. - Answer-FALSE
,2|Page
In a conventional activated sludge process, how much
oxygen is required per lb. of BOD removed? - Answer-0.8
to 1.2 lb oxygen /lb BOD
Which of the following conditions would least likely
contribute to rising sludge in secondary clarifiers? -
Answer-Clarifier hydraulic loading
In an activated sludge process bacteria release chemicals
called ________ that break down the food particles that
are adsorbed to the cell wall so that they can be absorbed
by the microorganism. - Answer-Enzymes
Acids should never be added to chlorine solutions
because they - Answer-Cause chlorine gas to be released
Chloramines are ____? - Answer-Combined chlorine
What are the characteristics for chlorine as used in
pollution control? - Answer-Chlorine gas is toxic, corrosive,
and heavier than air
,3|Page
Chlorine applied minus ____ equals chlorine residual -
Answer-Chlorine demand
Unlike chlorine, UV does not leave what in treated water?
- Answer-A residual
Coliform bacteria are: - Answer-Indicators
A _____ residual is attained after breakpoint chlorination. -
Answer-Free
If you need a chlorine residual of 1 mg/l, how many
pounds of chlorine must be applied each day if the flow is
2.5 mgd and the chlorine demand is 15 mg/l? - Answer-
334 lb/d
A total residual is also referred to as a ______ residual. -
Answer-Combined
Total and fecal coliform are pathogenic. - Answer-FALSE
, 4|Page
_________ = flow, mgd x chlorine dosage, mg/L x 8.34
lb/gal. - Answer-Feed Rate/Dose (lbs/day)
Sodium hypochlorite is manufactured by the reaction of
gaseous or liquid chlorine with a solution of _________
_________ to produce a liquid containing NaOCl. -
Answer-Sodium hypochlorite
At concentrations less than _____, chlorine gas is not
detectable by the human sense of smell. - Answer-1 ppm
A treatment plant uses sulfur dioxide to dechlorinate
effluent. An operator needs to adjust the sulfonator so that
the dosing concentration is 1.5 mg/l more than the chlorine
residual. Based on the following information, what should
the sulfonator feed rate be: design flow = 5 mgd; chlorine
dosage rate = 4 mg/l; chlorine residual = 0.9 mg/l -
Answer-100 lb/day
The UV dose represents the product of the rate of energy
emission (lamp intensity) and the time the organisms are
exposed to the germicidal energy at 254 nm. This can be
expressed by the equation: - Answer-Dose = intensity x
time (d=It)
