Specialist Exam Practice Questions And

Wisconsin Wastewater Operator Specialist Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• Which of the following processes is primarily responsible for the

removal of organic matter in wastewater?

• Filtration
• Activated sludge
• Chlorination
• Sedimentation

Rationale: Activated sludge uses microorganisms to biologically

degrade organic matter in wastewater.

• What is the primary purpose of a grit chamber?
• Remove organic solids 1 / 4

• Remove heavy inorganic solids
• Remove pathogens
• Reduce nutrients

Rationale: Grit chambers remove sand, gravel, and other heavy

inorganic particles that can damage equipment.

• What does BOD stand for in wastewater analysis?
• Biological Oxidation Demand
• Biochemical Oxygen Demand
• Basic Oxidation Difference
• Biotic Oxygen Depletion

Rationale: BOD measures the amount of oxygen microorganisms

consume to decompose organic matter in water.

• Which of the following is the primary disinfectant used in wastewater

treatment?

• Ozone
• Chlorine
• UV light
• Hydrogen peroxide

Rationale: Chlorine is widely used due to its effectiveness and ease of

application.

• Which unit process is used to separate solids from liquid by gravity?
• Filtration
• Aeration 2 / 4

• Sedimentation
• Coagulation

Rationale: Sedimentation allows solids to settle naturally under the

influence of gravity.

• What is the main function of an aeration tank?
• Remove nutrients
• Provide oxygen for microorganisms
• Settle sludge
• Remove grit

Rationale: Aeration tanks supply oxygen to support the growth of

microorganisms that digest organic matter.

• Which of the following pH levels is considered neutral?
• 3
• 5
• 7
• 9

Rationale: A pH of 7 is neutral; values below 7 are acidic, and above

• are basic.
• What is the first step in wastewater treatment?
• Secondary treatment
• Preliminary treatment
• Tertiary treatment
• Disinfection 3 / 4

Rationale: Preliminary treatment removes large solids, debris, and

grit before biological treatment.

• Which of the following microorganisms is most commonly used in the

activated sludge process?

• Viruses
• Protozoa
• Bacteria
• Algae

Rationale: Bacteria are the primary decomposers of organic matter

in activated sludge systems.

10. Sludge volume index (SVI) is a measure of:

• Nutrient concentration
• Settling characteristics of sludge
• Oxygen demand
• Chlorine demand

Rationale: SVI evaluates how well sludge settles in secondary

clarifiers.

• Which of the following describes nitrification?
• Conversion of nitrogen gas to ammonia
• Conversion of ammonia to nitrate
• Conversion of nitrate to nitrogen gas
• Denitrification of organic matter
• / 4