Modelling the advanced oxidation of the pharmaceutical compound metronidazole in single- and multi-lamp tubular photoreactors

A model was developed to predict the removal of metronidazole utilizing the UV/H₂O₂ AOP. The rate constant for the reaction between metronidazole and the hydroxyl radical was determined ... The model was able to predict an optimal initial H₂O₂ dose, and the inhibitory effects of high H₂O₂ doses and bicarbonate ions in the aqueous solution. Simulations were run for three reactors, at various influent H₂O₂ doses and reactor radii ... 4.9% to 13% removal was predicted for the single-lamp photoreactors, while 14% to 41% was predicted for the multi-lamp photoreactor. Selection of a reactor radius for maximum metronidazole removal varied with influent H₂O₂ concentration. The lowest operational cost of $0.05 per mmol removed was projected for the multi-lamp photoreactor. Operationlly, it was cost effective to utilize higher UV lamp output (36W), while keeping influent H₂O₂ concentration low (25mg/L).