WASTE WATER OPERATOR LV 1 EXAM
PREP WITH DETAILED ANSWERS 2026
In the activated sludge process, some of the activated sludge must be wasted to...
A. Prevent excessive solid buildup
B. Prevent clogging of the sludge return line
C. Prevent overloading of sludge return pumps
D. Increase digester gas production - ANSWERSA. Prevent excessive solid buildup
The best operating strategy for feeding primary sludge to an anaerobic digester is to
feed...
A. Several time a day
B. Large quantities once or twice a day
C. Once a day
D. When the volatile solids drop below 60% - ANSWERSA. Several time a day
Why is scum skimmed from the liquid surface of a primary settling tank?
A. To reduce load on the digester
B. To eliminate interference with sludge removal
C. To allow aeration of the tank contents
D. To reduce odor and insect nuisance - ANSWERSB. To eliminate interference with
sludge removal
Which of the following test would give the fastest indication of toxicity in an activated
sludge process?
A. Oxygen Uptake Rate (OUR)
B. Settleometer
C. MLSS
D. Microscopic Observation - ANSWERSA. Oxygen Uptake Rate (OUR)
Filamentous bulking of activated sludge may be controlled temporarily by...
A. Adding sodium chloride to the aeration tank
B. Spraying water on the aeration tank surface
C. Carefully chlorinating the return sludge and mixed liquor
D. Aerating the final settling tank - ANSWERSC. Carefully chlorinating the return sludge
and mixed liquor
, Since reaction rates are lower during the winter, the operator of an activated sludge
plant will usually...
A. Increase dissolved oxygen levels
B. Decrease MCRT
C. Decrease wasting
D. Increase MCRT - ANSWERSD. Increase MCRT
In a healthy activated sludge process which of the following organisms will most likely
be found in the greatest numbers?
A. Stalked Ciliates
B. Amoebas
C. Free swimming ciliates
D. Nymphs - ANSWERSA. Stalked Ciliates
Alkalinity is a measure of the ability of wastewater to...
A. Neutralize base
B. Neutralize acid
C. Dissolve organics
D. Maintain constant temperature - ANSWERSB. Neutralize acid
What is one advantage of a COD test over a BOD test?
A. Shorter test time
B. More accurate
C. Safer
D. Less chemicals needed - ANSWERSA. Shorter test time
Fecal coliform results are reported as MPN per...
A. 10 mL
B. 50 mL
C. 100 mL
D. 1,000 mL - ANSWERSC. 100 mL
A BOD can be removed from the incubator at 5 days plus of minus...
A. 1 hour
B. 2 hours
C. 3 hours
D. 4 hours - ANSWERSC. 3 hours
When performing an MPN the sample dilution is considered positive when...
PREP WITH DETAILED ANSWERS 2026
In the activated sludge process, some of the activated sludge must be wasted to...
A. Prevent excessive solid buildup
B. Prevent clogging of the sludge return line
C. Prevent overloading of sludge return pumps
D. Increase digester gas production - ANSWERSA. Prevent excessive solid buildup
The best operating strategy for feeding primary sludge to an anaerobic digester is to
feed...
A. Several time a day
B. Large quantities once or twice a day
C. Once a day
D. When the volatile solids drop below 60% - ANSWERSA. Several time a day
Why is scum skimmed from the liquid surface of a primary settling tank?
A. To reduce load on the digester
B. To eliminate interference with sludge removal
C. To allow aeration of the tank contents
D. To reduce odor and insect nuisance - ANSWERSB. To eliminate interference with
sludge removal
Which of the following test would give the fastest indication of toxicity in an activated
sludge process?
A. Oxygen Uptake Rate (OUR)
B. Settleometer
C. MLSS
D. Microscopic Observation - ANSWERSA. Oxygen Uptake Rate (OUR)
Filamentous bulking of activated sludge may be controlled temporarily by...
A. Adding sodium chloride to the aeration tank
B. Spraying water on the aeration tank surface
C. Carefully chlorinating the return sludge and mixed liquor
D. Aerating the final settling tank - ANSWERSC. Carefully chlorinating the return sludge
and mixed liquor
, Since reaction rates are lower during the winter, the operator of an activated sludge
plant will usually...
A. Increase dissolved oxygen levels
B. Decrease MCRT
C. Decrease wasting
D. Increase MCRT - ANSWERSD. Increase MCRT
In a healthy activated sludge process which of the following organisms will most likely
be found in the greatest numbers?
A. Stalked Ciliates
B. Amoebas
C. Free swimming ciliates
D. Nymphs - ANSWERSA. Stalked Ciliates
Alkalinity is a measure of the ability of wastewater to...
A. Neutralize base
B. Neutralize acid
C. Dissolve organics
D. Maintain constant temperature - ANSWERSB. Neutralize acid
What is one advantage of a COD test over a BOD test?
A. Shorter test time
B. More accurate
C. Safer
D. Less chemicals needed - ANSWERSA. Shorter test time
Fecal coliform results are reported as MPN per...
A. 10 mL
B. 50 mL
C. 100 mL
D. 1,000 mL - ANSWERSC. 100 mL
A BOD can be removed from the incubator at 5 days plus of minus...
A. 1 hour
B. 2 hours
C. 3 hours
D. 4 hours - ANSWERSC. 3 hours
When performing an MPN the sample dilution is considered positive when...
