Process Simulation of Fenton Oxidation for Ibuprofen Degradation in Wastewater Using Aspen Plus: Iron Recovery and Techno-Economic Evaluation

Ibuprofen is one of the most consumed pharmaceutical and is only partially removed by conventional wastewater treatment. Fenton oxidation can degrade it, but reagent use, ferric sledge and residual iron limit its application. A steady-state Aspen Plus V11 flowsheet (acidification, Fenton oxidation, neutralization, iron oxidation/precipitation, and solid–liquid separation) was developed for a concentrated ibuprofen stream (150 mg/L; 50 m3/d). Because the kinetics were not calibrated experimentally, the model was verified with an independent mass balance, and its sensitivity to oxidant and catalyst dose, oxidant utilization and by-product pathway was quantified. At the design H2O2 dose (0.86 times the stoichiometric demand), ibuprofen conversion was 86.0%, an oxidant limited upper bound; oxidant utilization efficiencies of 0.50–0.75 gave 43–64%. After correcting for undissolved oxygen, COD and TOC removals were 46.8% and 39.6%, and the effluent retained 76.3 mg/L benzoic acid and 134 mg/L dissolved iron, far above the 1–2 mg/L guideline values for iron. Reagent cost was 0.956 USD/m3 (90% interval: 0.773–1.15 USD/m3), or 5.31 USD per kg COD removed. The framework can be transferred to similar wastewaters after recalibration, and the results define the experiments required.