Math
Detention Time Calculation with Extraneous Data
Practice calculating detention time for an aeration basin. Exam-style question with unit conversion traps, worked solution, and all answer choices explained.
Sample Wastewater Exam Questions with Explanations
Free wastewater treatment operator exam questions with detailed explanations for every answer choice. See how we explain all four options — not just the correct one.
Math
Math
Pounds Formula: BOD Removal Calculation
Calculate BOD removal in lbs/day using the pounds formula. Includes gpm-to-MGD conversion trap, step-by-step solution, and all answer choices explained.
Math
F:M Ratio with MLVSS Derivation
Calculate the F:M ratio when you must derive MLVSS from MLSS and VSS%. Multi-step problem with primary effluent BOD, dual basins, and extraneous data.
Math
Surface Overflow Rate (SOR) for a Circular Clarifier
Calculate clarifier surface overflow rate from diameter and flow. Common trap: using diameter instead of radius. Full worked solution included.
Math
SVI Calculation from Settleometer and MLSS
Calculate the Sludge Volume Index from a 30-minute settleometer test. Covers the SVI formula, unit conversion trap (mL vs L), and interpretation.
Pumping
Activated Sludge
Activated Sludge
Rising Sludge in Secondary Clarifier (Denitrification)
Diagnose and correct rising sludge caused by denitrification in the secondary clarifier. Troubleshooting scenario with all answer choices explained.
Activated Sludge
SVI Interpretation and Filamentous Bulking Control
Interpret a high SVI with filamentous organisms and choose the correct operational response. Covers RAS chlorination and F:M adjustment.
Disinfection
Disinfection
Chlorine Demand vs Dosage vs Residual
Distinguish between chlorine dosage, demand, and residual. Essential disinfection concept with calculation and all answer choices explained.
Disinfection
Breakpoint Chlorination Curve Interpretation
Interpret the breakpoint chlorination curve phases: demand, combined residual, breakpoint dip, and free residual. Exam question with full explanation.
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