Addressing the Challenge of Wastewater Upcycling Through Cavitation-Plasma Synergy: From Pilot to Semi-Industrial Scale.

Pharmaceutical residues, especially non-steroidal anti-inflammatory drugs (NSAIDs), are emerging contaminants that hinder sustainable water management and limit wastewater upcycling. In this work, we address the challenge of wastewater upcycling via the scale-up of a hybrid advanced oxidation process (AOP) that couples hydrodynamic cavitation (HC) and non-thermal electrical discharge (ED) plasma, and that will enable the in situ generation of ROS. In order to demonstrate process scalability, the hybrid HC/ED plasma system was initially validated at pilot scale (600 L h-1) and subsequently up-scaled to a semi-industrial reactor (3200 L h-1), specifically designed starting from the pilot unit. The effective exploitation of HC/ED plasma synergy led to the process achieving the quantitative degradation of model pollutants, specifically ibuprofen and diclofenac (10 mg/L), in competitive times (13 passes) and without detectable byproducts, thereby validating the process' robustness and successful scale-up. Although current wastewater treatment plants (WWTPs) recover nutrients from sludge, biologically treated effluents still contain pharmaceutical residues. This work therefore, potentially solves this issue by providing a sustainable strategy for complete wastewater upcycling in WWTPs, delivering safe regenerated water for agricultural and irrigation reuse, while closing the water cycle.