Treatment Operator Exam Level II Practice

British Columbia ROWP Wastewater Treatment Operator Exam Level II Practice Exam 100 Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of secondary treatment in a wastewater

system?

• Remove grit
• Disinfect pathogens
• Reduce BOD and suspended solids
• Separate sand and debris

Rationale: Secondary treatment focuses on biological reduction of BOD

and TSS using microbial processes.

• Which biological process is most commonly used in secondary

wastewater treatment? 1 / 4

• Chemical coagulation
• Activated sludge
• Membrane distillation
• Chlorination

Rationale: Activated sludge is the most widely used biological process for

secondary treatment.

3. In an aeration basin, low dissolved oxygen typically results in:

• Increased nitrification
• Filamentous bacteria growth
• Reduced sludge age
• Lower MLSS

Rationale: Low DO favours filamentous organisms, which can cause

bulking.

• What is the primary purpose of a clarifier in a biological treatment

system?

• Add oxygen
• Remove pathogens
• Settle solids
• Remove grit 2 / 4

Rationale: Clarifiers allow biological solids to settle for recycling or

wasting.

5. A high F/M ratio typically results in:

• Old sludge
• Young sludge
• High SRT
• Nitrifying conditions

Rationale: High F/M means more food per microorganism, leading to

young, rapidly growing biomass.

• What does SRT measure?
• Flow rate
• Solids loading
• Average time solids remain in system
• Clarifier retention time

Rationale: SRT indicates how long biomass stays in the system and controls

microbial populations.

• Which parameter best indicates organic loading to a treatment plant? 3 / 4

A. TSS

• pH

C. BOD

• Temperature

Rationale: BOD reflects the biodegradable organic load entering the plant.

8. A sludge bulking condition is most likely due to:

• High DO
• Low DO
• High alkalinity
• Low temperature

Rationale: Low DO often promotes filamentous bacteria causing bulking.

• What is the main purpose of chlorination?
• Reduce TSS
• Remove BOD
• Disinfection
• Remove nutrients

Rationale: Chlorination is primarily used to kill or inactivate pathogens.

• Which measurement is most commonly used to determine biomass

concentration in activated sludge?

• / 4