Practice Exam Questions And Correct

Montana Wastewater Operator Class 1 Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a wastewater treatment plant?
• Generate electricity
• Protect public health and the environment
• Provide drinking water
• Reduce stormwater flow

Rationale: The main goal of a wastewater treatment plant is to

remove pollutants from sewage to protect public health and prevent environmental contamination.

• Which of the following is a characteristic of domestic wastewater?
• High industrial chemicals 1 / 4

• Contains human waste, food waste, and household detergents
• Pure water with minor impurities
• Only stormwater runoff

Rationale: Domestic wastewater primarily comes from households

and contains organic matter, nutrients, and some chemicals from household products.

• Which unit process is typically used to remove large solids from

wastewater?

• Aeration
• Screening
• Chlorination
• Filtration

Rationale: Screening physically removes large debris like sticks, rags,

and plastics to prevent damage to downstream equipment.

• What is the purpose of a grit chamber?
• Remove fats and oils
• Remove dissolved chemicals
• Remove sand, gravel, and other heavy particles
• Neutralize pH

Rationale: Grit chambers slow the flow of wastewater, allowing

heavier particles to settle and protecting pumps and pipes from abrasion. 2 / 4

• Which microorganism is commonly used in the activated sludge

process?

• Algae
• Viruses
• Bacteria
• Protozoa

Rationale: Bacteria metabolize organic matter in the wastewater,

breaking it down into simpler compounds in the activated sludge process.

• What is the purpose of primary sedimentation?
• Chlorinate water
• Aerate wastewater
• Remove settleable solids
• Add nutrients

Rationale: Primary sedimentation tanks allow solids to settle by

gravity, reducing the load on secondary treatment processes.

• Which factor most affects the rate of settling in a sedimentation tank?
• Color of wastewater
• Particle size and density
• Temperature alone
• pH only

Rationale: Larger and denser particles settle faster due to gravity;

smaller or lighter particles may remain suspended. 3 / 4

• What is BOD a measure of in wastewater?
• Chemical composition
• Amount of oxygen required by microorganisms to decompose

organic matter

• pH level
• Heavy metal concentration

Rationale: Biochemical Oxygen Demand (BOD) indicates the organic

pollution level by measuring the oxygen microorganisms consume to decompose it.

• What does TSS stand for in wastewater analysis?
• Total Soluble Solids
• Total Saturated Salts
• Total Suspended Solids
• Total Sewage Sample

Rationale: TSS measures particles suspended in wastewater,

indicating the amount of solids that may cause settling or treatment issues.

• Which chemical is commonly used for disinfection in wastewater

treatment?

• Ammonia
• Chlorine
• Lime
• Fluoride
• / 4