analysis of variance results of orthogonal assay experiment are listed in Table 4. In which, the antibiotic removals was notably impacted by flow type for tetracycline in summer, lomefloxacin and roxithromycin in winter, norfloxacin and ofloxacin in both seasons, by substrate for ofloxacin in summer and lomefloxacin in winter, by plant for norfloxacin and erythromycin in winter, ofloxacin and tetracycline in both seasons, by hydraulic loading rate for ofloxacin and ciprofloxacin in summer, norfloxacin, oxytetracycline, and erythromycin in winter.