Removal of Emerging Contaminants in a Membrane Bioreactor Coupled with Ozonation: Optimization by Response Surface Methodology (RSM)

摘要

The combination of chemical and biological treatments is an efficient approach for a complete removal of emerging contaminants such as pharma-ceuticals. In this study, the removal of a mixture of anti-inflammatories (naproxen and diclofenac), antibiotics (azithromycin and trimethoprim), and hormones (levonorgestrel and medroxyprogesterone) was investigated using a membrane bioreactor (MBR) coupled with an ozonation system. The results showed complete removal of selected Pharmaceuticals only after 50 days of the experiment in the MBR+O_3 system, while in the MBR system the average removal rate was 35. Response surface methodology (RSM) was also utilized to statistically analyze the effects of process parameters and optimize the experimental conditions. Based on the RSM results, experiment time significantly impacted COD, BOD, and TDS removal. Also, the optimal conditions for ozonation time and ozone dose were determined to be 4 min and 5 mg/l, respectively. Based on the optimization approach achieved by RSM., the final concentrations of 44.3, 12.3, and 51.6 mg/l were obtained for COD, BOD, and TDS, respectively.