Application of Ozonation-Based Processes to Reduce Environmental Impact of Waste Antibiotics

The aim of the work was to determine the efficiency of direct ozonation, ozonation at elevated pH, ozonation at elevated pH with the addition of hydrogen peroxide, catalytic ozonation, photo-catalytic ozonation, ozonation with Fenton oxidation and ozonation with photo-Fenton oxidation for removal of waste Vancomycin from industrial wastewater. Vancomycin belongs to the glycopeptide antibiotics, preventing cell wall synthesis in susceptible bacteria. Batch oxidation experiments were carried out at room and elevated temperatures in a 300 mL laboratory bubble column. Additional toxicity test with Vibrio fischeri was accomplished to determine the environmental toxicity of treated and untreated wastewater. It was confirmed that a two-stage ozonation reaction takes place, more efficient at elevated temperatures. Complete mineralization was not achieved with any type of enhanced ozonation, as the decomposition efficiencies were up to 94%. Based on TOC (Total Organic Carbon) and COD (Chemical Oxygen Demand) determination, ozonation at elevated temperature with photo–Fenton oxidation was the most successful. Toxicity tests revealed significant detoxification of model wastewater in most of the applied oxidation processes. In most of the cases obtained inhibitions that were higher than 10%, while in photo-catalytic ozonation it was reduced below 10%.