Integration of hydrodynamic cavitation and preozonation: a physicochemical strategy for effectively addressing intracellular odorants from filamentous cyanobacteria.

This study introduces hydrodynamic cavitation-integrated preozonation (HCPO), a novel physicochemical strategy that synergistically combines hydrodynamic cavitation (HC) with preozonation to eliminate intracellular taste-and-odor compounds, like 2-methylisoborneol (2-MIB) and geosmin (GSM), from filamentous cyanobacteria. Unlike conventional peroxone preozonation, which fails to degrade cell-bound odorants and requires unstable hydrogen peroxide handling, HCPO employs a Venturi-based HC unit to physically enhance the disruption of cyanobacterial cells while upgrading ozone dispersion and radical generation. Rigorous experimentation demonstrated the superiority of HCPO, achieving 86% and 77% removal of intracellular 2-MIB and GSM within 30 minutes, far exceeding those of standalone methods (p < 0.001). Mechanistically, cavitation amplified •OH production by 141% and extended ozone residence time, enabling near-complete oxidation of released odorants. Multidimensional validation via Scanning Electron Microscope (SEM), Excitation-Emission Matrix (EEM) fluorescence spectroscopy, and radical quantification confirmed irreversible cell lysis and enhanced degradation kinetics. Critically, HCPO minimized bromate formation (<10 ppb) through optimized oxidant utilization and reduced ozone dosage (30-50% lower), yielding operational costs of 0.17-0.25 kWh/m3. This innovation resolves a significant limitation in drinking water treatment by concurrently addressing dissolved and cell-bound contaminants, offering a scalable, safety-enhanced alternative that aligns with sustainable water purification frameworks.