Level I Practice Exam Questions And

Wyoming Wastewater Treatment Operator Level I 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?
• Produce drinking water
• Remove pollutants from wastewater before discharge
• Generate electricity
• Store sewage for future use

Rationale: The main purpose of wastewater treatment is to remove

pollutants and protect public health and the environment.

• Which of the following is a physical method of wastewater treatment?
• Screening
• Activated sludge
• Trickling filter 1 / 4

• Chlorination

Rationale: Screening is a physical process used to remove large solids

from wastewater.

• What is the typical pH range of influent wastewater?
• 2.0–4.0
• 6.5–8.5
• 9.0–11.0
• 12.0–14.0

Rationale: Most municipal wastewater has a pH between 6.5 and

8.5.

• Which process uses microorganisms to break down organic matter in

wastewater?

• Filtration
• Biological treatment
• Sedimentation
• Chlorination

Rationale: Biological treatment relies on microorganisms to degrade

organic pollutants.

5. The term BOD stands for:

• Biochemical Oxidation Demand
• Biochemical Oxygen Demand
• Basic Oxygen Determination
• Biological Oxidation Degree 2 / 4

Rationale: BOD measures the amount of dissolved oxygen required

by microorganisms to decompose organic material in water.

6. A high BOD in wastewater indicates:

• Low organic pollution
• High organic pollution
• High dissolved oxygen
• Low microbial activity

Rationale: BOD reflects the organic load; higher BOD means more

organic matter present.

• Which unit process is used to remove settleable solids from

wastewater?

• Aeration
• Sedimentation
• Filtration
• Chlorination

Rationale: Sedimentation allows heavier solids to settle out by

gravity.

• What is the main purpose of chlorination in wastewater treatment?
• Remove solids
• Reduce BOD
• Disinfect wastewater
• Neutralize pH

Rationale: Chlorination kills or inactivates pathogenic organisms. 3 / 4

• Which of the following is a typical characteristic of primary sludge?
• High solids content
• High oxygen demand
• High nitrates
• High alkalinity

Rationale: Primary sludge is composed of settled solids, which are

concentrated and have a high solids content.

• The process of removing nitrogen from wastewater biologically

is called:

• Sedimentation
• Nitrification-denitrification
• Coagulation
• Chlorination

Rationale: Biological nitrogen removal occurs through nitrification

(ammonia to nitrate) and denitrification (nitrate to nitrogen gas).

• Which safety equipment is required when handling chlorine gas?
• Earplugs
• Safety goggles only
• Respirator and full protective clothing
• Hard hat only

Rationale: Chlorine gas is toxic; proper PPE includes respirators and

protective clothing.

• / 4