Occurrence and behavior of pharmaceuticals in sewage treatment plants in eastern China

The occurrence and removal efficiency of seven pharmaceuticals （norfloxacin, trimethoprim, roxithromycin, sulfamethoxazole, ibuprofen, diclofenac and carbamazepine） were determined in three sewage treatment plants （STPs） with anaerobic/anoxic/oxic, anoxic/oxic and oxidation ditches processes in Xuzhou City, Eastern China. The results showed that seven pharmaceuticals were detected in the influent samples with concentrations ranging from 93 to 2540 ng·L^-1. The removal of these substances among the three different STPs varied from 36 to 84%, with the highest performance obtained by the wastewater treatment works with tertiary treatment （sand filtration）. Most of the compounds were removed effectively during biologic treatment while sand filtration treatment also made a contribution to the total elimination of most pharmaceuticals. The efficiency comparison of the three sewage treatment processes showed that the STP which employed anaerobic/anoxic/oxic was more effective to remove pharmaceuticals than the oxidation ditches and anoxic/oxic.