Sustainable Wastewater Reclamation and Industrial Reuse via Integrated Membrane Filtration and Hybrid Hydrodynamic Cavitation: A Process Simulation

Facing increasing water scarcity and climate-related challenges, transitioning from linear consumption to closed-loop water circularity has become essential. This study presents a comprehensive process and energy simulation of a full-scale wastewater reclamation plant treating 1000 m3/h of municipal wastewater designed for high-grade industrial reuse. The multi-barrier treatment train, modeled in SuperPro Designer® v.9.5 and Hydranautics IMSDesignTM v.20.1, integrates activated sludge secondary treatment with microfiltration (MF), a three-stage reverse osmosis unit (RO, 80% recovery), UV photolysis, and a hybrid hydrodynamic cavitation reactor (HC) supplemented with ozone and hydrogen peroxide. The simulation demonstrates an overall clean water recovery of 75.5% (754.6 m3/h of reusable water) with deep organic mineralization: Chemical Oxygen Demand (COD) is reduced from 339.8 to 0.09 mg/L and Total Organic Carbon (TOC) from 115.1 to 0.03 mg/L, complying with quality standards for industrial reuse (Italian D.M. 185/2003) and agronomic Class A limits (Regulation EU 2020/741). The specific energy consumption for the entire plant is 1.98 kWh/m3 (1.55 kWh/m3 for the tertiary reuse section and 1.03 kWh/m3 for secondary treatment), corresponding to an electricity operating cost of approximately 0.66 €/m3 of treated water (at 0.25 €/kWh). This work provides a verified engineering framework demonstrating the technical and energetic feasibility of closed-loop water reclamation.