Page 1 of 111
Arizona Wastewater Treatment Operator Grade 1
Exam Questions and Correct Answers with
EXPLANATIONS LATEST THIS YEAR
SUMMARIZED EXAM COVERAGE
The Arizona Grade 1 Wastewater Operator Exam focuses on basic wastewater treatment principles,
including preliminary, primary, and secondary treatment processes, along with simple disinfection
methods. It tests understanding of wastewater characteristics, flow measurement, and basic operator
math. Candidates must also understand basic equipment operation such as pumps and valves, along
with routine maintenance procedures. Safety regulations, including PPE and confined space awareness,
are included. The exam also introduces basic lab testing, process monitoring, and Arizona ADEQ
compliance requirements.
1.
A wastewater operator observes high levels of debris entering the treatment plant. What is the first
treatment process designed to remove this material?
A. Chlorination
B. Screening
C. Sedimentation
D. Aeration
Answer: B
Rationale: Screening removes large debris before further treatment.
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2.
A plant records increasing solids settling in the primary clarifier. What process is primarily occurring
here?
A. Disinfection
B. Sedimentation
C. Aeration
D. Filtration
Answer: B
Rationale: Primary clarifiers rely on settling of solids.
3.
An operator measures influent flow at 2 MGD. What does MGD stand for?
A. Million Gallons Daily
B. Measured Gallons Distribution
C. Million Gallons Discharged
D. Metered Gallons Delivered
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Answer: A
Rationale: MGD means million gallons per day.
4.
A wastewater sample shows high Biochemical Oxygen Demand (BOD). What does this indicate?
A. Low organic pollution
B. High organic pollution
C. No contamination
D. Excess chlorine presence
Answer: B
Rationale: High BOD means high organic waste load.
5.
A centrifugal pump stops delivering flow suddenly. What is a likely cause?
A. Increased oxygen levels
B. Loss of prime
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C. Excess sludge removal
D. High chlorine dose
Answer: B
Rationale: Pumps lose efficiency when not primed.
6.
An operator is required to disinfect treated wastewater. What is the most common method used?
A. Sedimentation
B. Chlorination
C. Screening
D. Grinding
Answer: B
Rationale: Chlorine is widely used for disinfection.
7.
A wastewater plant experiences foul odors in the primary clarifier. What is the most likely cause?
Arizona Wastewater Treatment Operator Grade 1
Exam Questions and Correct Answers with
EXPLANATIONS LATEST THIS YEAR
SUMMARIZED EXAM COVERAGE
The Arizona Grade 1 Wastewater Operator Exam focuses on basic wastewater treatment principles,
including preliminary, primary, and secondary treatment processes, along with simple disinfection
methods. It tests understanding of wastewater characteristics, flow measurement, and basic operator
math. Candidates must also understand basic equipment operation such as pumps and valves, along
with routine maintenance procedures. Safety regulations, including PPE and confined space awareness,
are included. The exam also introduces basic lab testing, process monitoring, and Arizona ADEQ
compliance requirements.
1.
A wastewater operator observes high levels of debris entering the treatment plant. What is the first
treatment process designed to remove this material?
A. Chlorination
B. Screening
C. Sedimentation
D. Aeration
Answer: B
Rationale: Screening removes large debris before further treatment.
, Page 2 of 111
2.
A plant records increasing solids settling in the primary clarifier. What process is primarily occurring
here?
A. Disinfection
B. Sedimentation
C. Aeration
D. Filtration
Answer: B
Rationale: Primary clarifiers rely on settling of solids.
3.
An operator measures influent flow at 2 MGD. What does MGD stand for?
A. Million Gallons Daily
B. Measured Gallons Distribution
C. Million Gallons Discharged
D. Metered Gallons Delivered
, Page 3 of 111
Answer: A
Rationale: MGD means million gallons per day.
4.
A wastewater sample shows high Biochemical Oxygen Demand (BOD). What does this indicate?
A. Low organic pollution
B. High organic pollution
C. No contamination
D. Excess chlorine presence
Answer: B
Rationale: High BOD means high organic waste load.
5.
A centrifugal pump stops delivering flow suddenly. What is a likely cause?
A. Increased oxygen levels
B. Loss of prime
, Page 4 of 111
C. Excess sludge removal
D. High chlorine dose
Answer: B
Rationale: Pumps lose efficiency when not primed.
6.
An operator is required to disinfect treated wastewater. What is the most common method used?
A. Sedimentation
B. Chlorination
C. Screening
D. Grinding
Answer: B
Rationale: Chlorine is widely used for disinfection.
7.
A wastewater plant experiences foul odors in the primary clarifier. What is the most likely cause?
