Exam Practice Questions And Correct

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

• Which of the following is the primary purpose of a wastewater

treatment plant?

• Increase water temperature
• Reduce water flow
• Remove pollutants from wastewater
• Store water for future use

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

remove pollutants from wastewater to protect public health and the environment. 1 / 4

2. The Clean Water Act (CWA) is designed to:

• Promote groundwater contamination
• Regulate discharges of pollutants into waters of the United States
• Control air pollution
• Manage hazardous waste only

Rationale: The CWA regulates pollutant discharges into surface

waters and ensures water quality standards are met.

• Which microorganism is primarily responsible for breaking down

organic matter in wastewater?

• Viruses
• Bacteria
• Protozoa
• Algae

Rationale: Bacteria are the primary decomposers in wastewater

treatment, breaking down organic compounds.

• What is the function of a grit chamber in wastewater treatment?
• Remove oils and grease
• Remove sand, gravel, and heavy solids
• Filter microorganisms
• Disinfect water

Rationale: Grit chambers remove heavy, inorganic solids to prevent

damage to pumps and other equipment. 2 / 4

• Which of the following is considered a primary treatment process?
• Activated sludge
• Trickling filter
• Sedimentation
• Chlorination

Rationale: Sedimentation removes settleable solids and is a key

component of primary treatment.

6. BOD stands for:

• Biological Oxygen Demand
• Biochemical Oxidation Density
• Biochemical Oxygen Demand
• Basic Organic Decomposition

Rationale: BOD measures the amount of oxygen microorganisms

require to decompose organic matter in water.

7. A Class C wastewater operator is primarily responsible for:

• Supervising all Class A operators
• Operating a small wastewater treatment plant or a specific

process unit under supervision

• Designing treatment plants
• Inspecting municipal drinking water systems

Rationale: Class C operators typically handle small plants or operate

specific units under supervision. 3 / 4

• Which of the following best describes anaerobic digestion?
• Digestion in the presence of oxygen
• Digestion in the absence of oxygen
• A chemical oxidation process
• Filtration through sand

Rationale: Anaerobic digestion uses bacteria that function without

oxygen to break down organic matter.

9. The primary purpose of chlorine in wastewater treatment is to:

• Remove grit
• Increase BOD
• Disinfect and kill pathogens
• Remove suspended solids

Rationale: Chlorine is used to disinfect treated wastewater before

discharge to prevent disease.

10. Sludge that has been thickened and dewatered is typically:

• Returned to the headworks
• Disposed of or further treated
• Sent to aeration tanks
• Used to disinfect effluent

Rationale: Dewatered sludge is usually disposed of or treated further

to reduce volume and stabilize organic matter.

• What is the typical pH range for municipal wastewater?
• 2–4
• / 4