Treatment Operator Exam Level IV Practice

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

• What is the primary objective of advanced biological nutrient removal

(BNR) in Level IV wastewater treatment?

• Reduce solids production
• Improve disinfection performance
• Remove nitrogen and phosphorus
• Increase alkalinity

Rationale: Advanced BNR specifically targets nutrient reduction, especially

N and P, to protect receiving waters.

• In an anoxic zone, which biochemical process is responsible for nitrogen

removal? 1 / 4

• Nitrification
• Denitrification
• Fermentation
• Methanogenesis

Rationale: Denitrifying bacteria convert nitrate to nitrogen gas under

anoxic conditions.

• Which parameter is most commonly used to control aerobic digestion?
• pH
• Mean cell residence time (MCRT)
• Chlorine residual
• Alkalinity

Rationale: Aerobic digesters rely on maintaining proper MCRT for volatile

solids breakdown.

• In membrane bioreactors (MBRs), what typically limits flux through the

membrane?

• Temperature
• pH imbalance
• Fouling layer accumulation
• Excess alkalinity

Rationale: Membrane fouling increases resistance and reduces flux. 2 / 4

• Which chemical is commonly used for phosphorus precipitation?
• Sodium hypochlorite
• Sodium hydroxide
• Ferric chloride
• Hydrogen peroxide

Rationale: Ferric salts bind with phosphate to form insoluble precipitates.

• What is the primary purpose of equalization tanks in advanced

treatment systems?

• Increase alkalinity
• Buffer flow and load variations
• Enhance disinfection
• Boost DO concentration

Rationale: Equalization mitigates hydraulic and organic fluctuations to

protect downstream processes.

• In a nitrifying system, what happens when pH drops below 6.5?
• Nitrification accelerates
• Nitrification slows or stops
• Denitrification increases 3 / 4

• Aeration demand decreases

Rationale: Nitrifiers are pH-sensitive and become inhibited at low pH.

• Which type of pump is most suitable for moving sludge with high solids

content?

• Centrifugal pump
• Progressive cavity pump
• Turbine pump
• Vertical inline pump

Rationale: Progressive cavity pumps handle viscous, high-solids sludge

well.

• What is the key operational issue associated with anaerobic digestion?
• Excess aeration
• High alkalinity
• Foaming and scum accumulation
• Oxidation of methane

Rationale: Anaerobic digesters often struggle with foam caused by FOG or

filamentous organisms.

• The F/M ratio in advanced biological treatment primarily influences:
• / 4