Multistage ozone and biological treatment system for real wastewater containing antibiotics

In this study, a multistage treatment system was proposed to treat real pharmaceutical wastewater containing the antibiotic amoxicillin. Ozonation (O-3), and ozonation combined with aerobic biodegradation, were performed. The real pharmaceutical wastewater presented a high concentration of organic matter (TOC: 803 mg C.L-1 and COD: 2775 mg O-2.L-1), significant amoxicillin content (50 mg L-1) and acute ecotoxicity (Aliivibrio fischeri aTU: 48.22). Ozonation proved to be effective for amoxicillin degradation (up to 99%) and the results also indicated the removal of the original colour of the wastewater, with average consumption of 1 g of ozone. However, the ozonation system alone could not achieve complete mineralization. Therefore, a combination of ozonation and biodegradation in a multistage system was proposed in order to improve cost and treatment efficiency. The multistage treatment system presented promising results, achieving degradation of more than 99% of the amoxicillin, more than 98% of the original chemical oxygen demand (COD), and 90% of initial toxicity, with the consumption of approximately 500 mg of ozone. This indicates that this system could prevent dangerous and biorecalcitrant antibiotics from entering water resources. (C) 2016 Elsevier Ltd. All rights reserved.