Practice Exam 100 Practice Questions

Maine Wastewater Operator Grade V Practice Exam 100 Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

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

Grade V facility?

• Remove large debris
• Reduce odors
• Improve effluent aesthetics
• Remove nutrients and remaining contaminants

Rationale: Advanced facilities focus on nutrient and high-level

contaminant removal beyond secondary treatment.

• Which process is most commonly used for biological nitrogen removal?
• Chlorination
• Sedimentation 1 / 3

• Nitrification–denitrification
• Filtration

Rationale: Nitrogen removal requires converting ammonia to nitrate, then

nitrate to nitrogen gas.

• The activated sludge process relies heavily on maintaining which

parameter?

• Chlorine residual
• Sludge drying time
• Mixed liquor suspended solids (MLSS)
• Grit load

Rationale: MLSS determines the biological population responsible for

treatment.

• Excessive filamentous bacteria in activated sludge cause what

condition?

• Rising sludge
• Bulking
• Struvite buildup
• Cavitation

Rationale: Filaments interfere with settling, causing bulking.

• Which parameter is essential for measuring oxygen uptake by

microorganisms? 2 / 3

A. TSS

B. BOD

• Alkalinity
• Hardness

Rationale: BOD measures the oxygen microorganisms consume to break

down organics.

• A low sludge age typically results in what condition?
• High nitrification
• Low F/M ratio
• Poor settling / pin floc
• Excess alkalinity

Rationale: Young sludge produces small, poorly settling floc.

• What gas is commonly produced during anaerobic digestion?
• Oxygen
• Nitrogen
• Methane
• Ozone

Rationale: Methane is a major by-product of anaerobic decomposition.

• Chlorine reacts with ammonia to form what compound?
• Hypochlorite
• Chloramines
• Free radicals
• / 3