Assess learners' ability to apply mass-balance principles to industrial wastewater treatment problems by setting up and solving steady-state and batch/continuous mass balances for flows, pollutant concentrations (BOD/COD/solids), reaction/removal rates, recycle/sludge streams, and chemical dosing; include unit conversions, clear assumptions, and troubleshooting of unit operations (e.g., equalization, reactors, clarifiers, adsorption) to compute unknown flow rates, concentrations, mass removal efficiencies, and sludge generation.