Treatment Operator Level 1 Practice Exam

Newfoundland and Labrador Wastewater Treatment Operator Level 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
• Produce drinking water
• Remove pollutants from wastewater
• Store wastewater

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

remove pollutants to protect public health and the environment.

• Which of the following is a physical method of wastewater treatment?
• Biological treatment
• Sedimentation
• Chlorination 1 / 4

• Nitrification

Rationale: Sedimentation is a physical process where solids settle out

from wastewater due to gravity.

• What is the typical first step in wastewater treatment?
• Biological treatment
• Screening
• Disinfection
• Sludge digestion

Rationale: Screening removes large debris such as sticks, rags, and

plastics from wastewater.

• Which type of wastewater contains mostly domestic sewage?
• Industrial wastewater
• Stormwater runoff
• Sanitary wastewater
• Groundwater

Rationale: Sanitary wastewater originates from households and

contains typical domestic sewage.

• What is the purpose of grit removal?
• Remove bacteria
• Reduce odor
• Prevent damage to equipment
• Increase pH 2 / 4

Rationale: Grit removal protects pumps and other mechanical

equipment from abrasion by sand and small stones.

• What is the typical unit used to measure flow in wastewater

treatment?

• Liters
• Cubic meters per day
• Kilograms
• Milligrams per liter

Rationale: Flow in treatment plants is usually measured in cubic

meters per day (m³/d).

• Which of the following is considered a secondary treatment process?
• Screening
• Activated sludge
• Grit removal
• Chlorination

Rationale: Activated sludge is a biological process that removes

dissolved and suspended organic matter.

• What is the function of aeration in wastewater treatment?
• Remove grit
• Promote biological oxidation of organic matter
• Clarify solids
• Filter water 3 / 4

Rationale: Aeration supplies oxygen to microorganisms, enabling

them to break down organic pollutants.

• Which of the following best describes BOD?
• Biochemical Oxygen Demand
• Biological Organic Detergent
• Basic Oxygen Dosage
• Biochemical Oxidation Depth

Rationale: BOD measures the amount of oxygen required by

microorganisms to decompose organic matter.

10. A high BOD in wastewater indicates:

• Low pollution
• Clear water
• High organic pollution
• Low microbial activity

Rationale: High BOD shows a large amount of organic matter, which

can deplete oxygen in receiving waters.

• What is the main purpose of primary sedimentation?
• Aerate wastewater
• Remove dissolved nutrients
• Remove settleable solids
• Disinfect wastewater

Rationale: Primary sedimentation allows solids to settle out by

gravity before biological treatment.

• / 4