Performance of anaerobic sequencing batch reactor in the treatment of pharmaceutical wastewater containing erythromycin and sulfamethoxazole mixture S. Aydin, B. Ince, Z. Cetecioglu, E. G. Ozbayram, A. Shahi, O. Okay, O. Arikan and O. Ince ABSTRACT This study evaluates the joint effects of erythromycinsulfamethoxazole (ES) combinations on anaerobic treatment efciency and the potential for antibiotic degradation during anaerobic sequencing batch reactor operation. The experiments involved two identical anaerobic sequencing batch reactors. One reactor, as control unit, was fed with synthetic wastewater while the other reactor (ES) was fed with a synthetic substrate mixture including ES antibiotic combinations. The inuence of ES antibiotic mixtures on chemical oxygen demand (COD) removal, volatile fatty acid production, antibiotic degradation, biogas production, and composition were investigated. The inuent antibiotic concentration was gradually increased over 10 stages, until the metabolic collapse of the reactors, which occurred at 360 days for the ES reactor. The results suggest that substrate/ COD utilization and biogas/methane generation affect performance of the anaerobic reactors at higher concentration. In addition, an average of 40% erythromycin and 37% sulfamethoxazole reduction was achieved in the ES reactor. These results indicated that these antibiotics were partly biodegradable in the anaerobic reactor system. S. Aydin (corresponding author) Z. Cetecioglu E. G. Ozbayram A. Shahi O. Arikan O. Ince Environmental Engineering Department, Istanbul Technical University, Maslak, Istanbul, Turkey E-mail: sevcan_aydn@hotmail.com B. Ince Institutes of Environmental Sciences, Bogazici University, Bebek, Istanbul, Turkey O. Okay Naval Architecture and Ocean Engineering Department, Istanbul Technical University, Maslak, Istanbul, Turkey Key words | anaerobic reactor, antibiotics, biodegradation, inhibition, pharmaceutical wastewater INTRODUCTION Pharmaceutical companies produce a large variety of pro- ducts that are used in both human and veterinary medicines. The manufacturing processes that prominent pharmaceutical companies use incorporate ve main processes: fermentation, extraction, chemical synthesis, for- mulation, and packaging. Although all of these processes produce some wastewater, it is the fermentation and syn- thesis operations that generate the largest amount of waste product; also, the wastewaters from these processes contain the highest amount of organic load (Sarantopoulos et al. ; Larsson et al. ). These active compounds also cannot be completely metabolized by the human body and cannot be removed completely in sewage treatment systems; they can be found in wastewater (Kümmerer ; Santos et al. ). Although the concentration of these antibiotics is relatively low in raw domestic wastewater, it can be sig- nicantly higher in hospital and pharmaceutical production facilitiesefuents, reaching around the 100500 mg/L level (Kümmerer ; Amin et al. ). This accumulation can adversely affect and change the microbial community that is present in biological waste- water treatment processes (Selvam et al. ; Resende et al. ). Two different biological treatment processes have been used to treat and control the wastewater that is produced as a byproduct of pharmaceutical manufacturing tech- niques: aerobic and anaerobic (Amin et al. ; Fountoulakis et al. ; Cetecioglu et al. ; Dorival- García et al. ). While activated sludge treatment has been used to treat wastewater, this process is unsuitable in situations where the chemical oxygen demand (COD) levels of the water exceed 1,500 mg/L (Chelliapan et al. ; Oktem et al. ). In recent years, research indicates that the high COD concentration of pharmaceutical indus- try wastewater makes anaerobic technology a favorable treatment (Shimada et al. ; Cetecioglu et al. ). This 1625 © IWA Publishing 2014 Water Science & Technology | 70.10 | 2014 doi: 10.2166/wst.2014.418 Downloaded from https://iwaponline.com/wst/article-pdf/70/10/1625/469986/1625.pdf by guest on 30 May 2020