Ozonation, advanced oxidation and hydrodynamic cavitation for removal of persistant pollutants

Ozone is commonly used in advanced oxidation processes (AOPs) in combinations with hydrogen peroxide (H2O2) and UV radiation (UV). Hydrodynamic cavitation (HC) has been experimentally proven to result in effects, typical of AOPs. Combinations of AOPs with O3, H2O2 and UV, and HC (with cavitation numbers less than 0.2, generated by various orifice plates and nozzles, with number of passes up to 12) were experimentally assessed on model water, containing organic matter. Various synthetic organic micropollutants (iohexol, diatrizoic acid and metaldehyde with concentrations of 10 μg L–1) were selected as the target compounds. At dosages of O3, H2O2 and UV above 2 mg L–1, 4 mg L–1 and 450 mJ cm–2, respectively, herein applied HC had no beneficial effect on target pollutants removal. At lower dosages of the aforementioned oxidants, HC was able to improve the removal rate of the target pollutants by as much as 15 %. Moreover, in terms of electrical energy consumption, the hybrid process with HC was found to be as efficient per order (90 %) of removal (EEO, kWh m–3 order–1).