Removal of azithromycin from wastewater using advanced oxidation processes (UV/H<SUB>2</SUB>O<SUB>2</SUB>) and moving-bed biofilm reactor (MBBR) by the response surface methodology (RSM)

Abstract

Antibiotics are among the major concerns in terms of environmental control due to their cumulative properties, adverse health effects on humans, and development of drug resistance. The present study aimed to investigate the efficiency of the combination of UV/H₂O₂ and moving-bed biofilm reactor (MBBR) systems in the removal of azithromycin from aqueous solutions using the response surface methodology (RSM). In the UV/H₂O₂ process, a low-pressure mercury vapor lamp with the power of eight Watts, wavelength of 254 nanometers, and intensity of 1.02 mw/cm² was used to determine the effects of pH, azithromycin concentration, hydrogen peroxide concentration, and contact time on the removal efficiency of azithromycin. According to the obtained results, the highest removal efficiency in the UV/H₂O₂ process was obtained with the azithromycin concentration of 2 mg/l. Therefore, 2 mg/l of azithromycin was selected as the optimal concentration with the highest removal efficiency. Following that, the optimal concentration of azithromycin was injected into the MBBR reactor. In the combined process of UV/H₂O₂ and MBBR, the highest removal efficiency of azithromycin was 91.2%. Therefore, it could be concluded that the combined system of UV/H₂O₂ and MBBR had the highest efficiency in the removal of azithromycin from aqueous solutions.