CA GRADE 2 WASTEWATER TREATMENT
OPERATOR EXAM 1
75+ (2026 Full Exam Kit) Solved Q&A | Correct & Verified Answers
100% Guarantee Pass
📋 DOCUMENT OVERVIEW 79 Qs
This document, "Ca Grade 2 Wastewater Treatment Operator Exam 1," covers various specific topics in
wastewater treatment, including anaerobic digestion, primary and secondary treatment processes,
aeration tank operations, activated sludge systems, and trickling filters. The document provides 79
questions with correct answers and detailed explanations, serving as a comprehensive review and study
guide for wastewater treatment operators to understand key concepts, identify knowledge gaps, and
reinforce their understanding of the subject matter. By utilizing this document, students can effectively
study and review critical concepts to prepare for wastewater treatment operator exams.
✓ Verified Answers ✓ Exam Ready ✓ Study Guide
Trusted by thousands of students and professionals worldwide
EXAM QUESTIONS
QUESTION 1
Which of the following best describes the methane content in a properly operating anaerobic
digester?
A) 40 to 50% by volume
B) 50 to 60% by volume
C) 65 to 70% by volume
D) 80 to 90% by volume
CORRECT ANSWER
C) 65 to 70% by volume
RATIONALE: A properly operating anaerobic digester has a methane content of 65 to 70% by volume, indicating
efficient digestion.
QUESTION 2
Trusted by thousands of students and professionals worldwide Page 1 of 26
, What is the primary purpose of adding chlorine gas to wastewater in terms of pH levels?
A) Increase the pH
B) Decrease the pH
C) Stabilize the pH
D) Neutralize the pH
CORRECT ANSWER
B) Decrease the pH
RATIONALE: Chlorine gas decreases the pH of wastewater, while options A, C, and D are incorrect as they do not
accurately describe the effect of chlorine gas on pH levels.
QUESTION 3
A candidate should identify that the primary function of a Parshall Flume is to
A) Regulate water pressure
B) Measure the flow rate
C) Treat wastewater
D) Remove sediment
CORRECT ANSWER
B) Measure the flow rate
RATIONALE: A Parshall Flume measures flow rate, while other options are unrelated to its primary function.
QUESTION 4
Which of the following is a characteristic of primary clarifiers in wastewater treatment?
A) 50-60% removal of settleable solids
B) 70-80% removal of dissolved solids
C) 95-99% removal of settleable solids
D) 40-50% removal of total suspended solids
CORRECT ANSWER
C) 95-99% removal of settleable solids
RATIONALE: Primary clarifiers typically achieve 95-99% removal of settleable solids, making option C correct. Options
A, B, and D are incorrect due to lower removal efficiencies or incorrect types of solids.
QUESTION 5
What is the difference between pumping scum from a primary clarifier and other substances at a
wastewater treatment plant?
A) Scum is less likely to clog pipes
Trusted by thousands of students and professionals worldwide Page 2 of 26
, B) Scum requires less pumping energy
C) Scum causes more piping problems
D) Scum is easier to handle
CORRECT ANSWER
C) Scum causes more piping problems
RATIONALE: Scum causes more piping problems due to its sticky nature and tendency to clog pipes.
QUESTION 6
Which of the following is an example of a condition that may cause excessive foaming in an aeration
tank?
A) High MLSS concentration
B) Low MLSS concentration
C) Insufficient aeration time
D) Inadequate tank mixing
CORRECT ANSWER
B) Low MLSS concentration
RATIONALE: Low MLSS concentration can lead to excess foaming, while high MLSS, insufficient aeration, and
inadequate mixing are not primary causes.
QUESTION 7
A professional should recognize that the M in F/M ratio represents
A) Mixed liquor fixed suspended solids
B) Microorganisms in the aeration tank
C) Mixed liquor volatile suspended solids
D) Mechanical equipment in the treatment process
CORRECT ANSWER
C) Mixed liquor volatile suspended solids
RATIONALE: The M in F/M ratio stands for mixed liquor volatile suspended solids, a key parameter in wastewater
treatment.
QUESTION 8
Which of the following correctly explains the effect of warmer temperatures on the settling rate of
solids in a clarifier?
A) Decrease the settling rate
B) Increase the settling rate
Trusted by thousands of students and professionals worldwide Page 3 of 26
OPERATOR EXAM 1
75+ (2026 Full Exam Kit) Solved Q&A | Correct & Verified Answers
100% Guarantee Pass
📋 DOCUMENT OVERVIEW 79 Qs
This document, "Ca Grade 2 Wastewater Treatment Operator Exam 1," covers various specific topics in
wastewater treatment, including anaerobic digestion, primary and secondary treatment processes,
aeration tank operations, activated sludge systems, and trickling filters. The document provides 79
questions with correct answers and detailed explanations, serving as a comprehensive review and study
guide for wastewater treatment operators to understand key concepts, identify knowledge gaps, and
reinforce their understanding of the subject matter. By utilizing this document, students can effectively
study and review critical concepts to prepare for wastewater treatment operator exams.
✓ Verified Answers ✓ Exam Ready ✓ Study Guide
Trusted by thousands of students and professionals worldwide
EXAM QUESTIONS
QUESTION 1
Which of the following best describes the methane content in a properly operating anaerobic
digester?
A) 40 to 50% by volume
B) 50 to 60% by volume
C) 65 to 70% by volume
D) 80 to 90% by volume
CORRECT ANSWER
C) 65 to 70% by volume
RATIONALE: A properly operating anaerobic digester has a methane content of 65 to 70% by volume, indicating
efficient digestion.
QUESTION 2
Trusted by thousands of students and professionals worldwide Page 1 of 26
, What is the primary purpose of adding chlorine gas to wastewater in terms of pH levels?
A) Increase the pH
B) Decrease the pH
C) Stabilize the pH
D) Neutralize the pH
CORRECT ANSWER
B) Decrease the pH
RATIONALE: Chlorine gas decreases the pH of wastewater, while options A, C, and D are incorrect as they do not
accurately describe the effect of chlorine gas on pH levels.
QUESTION 3
A candidate should identify that the primary function of a Parshall Flume is to
A) Regulate water pressure
B) Measure the flow rate
C) Treat wastewater
D) Remove sediment
CORRECT ANSWER
B) Measure the flow rate
RATIONALE: A Parshall Flume measures flow rate, while other options are unrelated to its primary function.
QUESTION 4
Which of the following is a characteristic of primary clarifiers in wastewater treatment?
A) 50-60% removal of settleable solids
B) 70-80% removal of dissolved solids
C) 95-99% removal of settleable solids
D) 40-50% removal of total suspended solids
CORRECT ANSWER
C) 95-99% removal of settleable solids
RATIONALE: Primary clarifiers typically achieve 95-99% removal of settleable solids, making option C correct. Options
A, B, and D are incorrect due to lower removal efficiencies or incorrect types of solids.
QUESTION 5
What is the difference between pumping scum from a primary clarifier and other substances at a
wastewater treatment plant?
A) Scum is less likely to clog pipes
Trusted by thousands of students and professionals worldwide Page 2 of 26
, B) Scum requires less pumping energy
C) Scum causes more piping problems
D) Scum is easier to handle
CORRECT ANSWER
C) Scum causes more piping problems
RATIONALE: Scum causes more piping problems due to its sticky nature and tendency to clog pipes.
QUESTION 6
Which of the following is an example of a condition that may cause excessive foaming in an aeration
tank?
A) High MLSS concentration
B) Low MLSS concentration
C) Insufficient aeration time
D) Inadequate tank mixing
CORRECT ANSWER
B) Low MLSS concentration
RATIONALE: Low MLSS concentration can lead to excess foaming, while high MLSS, insufficient aeration, and
inadequate mixing are not primary causes.
QUESTION 7
A professional should recognize that the M in F/M ratio represents
A) Mixed liquor fixed suspended solids
B) Microorganisms in the aeration tank
C) Mixed liquor volatile suspended solids
D) Mechanical equipment in the treatment process
CORRECT ANSWER
C) Mixed liquor volatile suspended solids
RATIONALE: The M in F/M ratio stands for mixed liquor volatile suspended solids, a key parameter in wastewater
treatment.
QUESTION 8
Which of the following correctly explains the effect of warmer temperatures on the settling rate of
solids in a clarifier?
A) Decrease the settling rate
B) Increase the settling rate
Trusted by thousands of students and professionals worldwide Page 3 of 26
