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Abstract
Municipal wastewater treatment plants (WWTPs) are an important source of pharmaceuticals
released into the environment. Understanding how various pharmaceuticals are distributed
and handled in WWTPs is a prerequisite to optimize their abatement. Here we investigated
the spatial distribution and removal efficiencies pharmaceuticals in China's WWTPs.
A total of 35 pharmaceuticals in wastewater samples from 12 WWTPs at different cities
of China were analyzed. Among these detected pharmaceuticals, caffeine showed the
highest concentration (up to 1775.98ngL(-1)) in the WWTP influent. In addition, there
were significant regional differences in pharmaceutical distribution with higher influent
concentrations of total pharmaceuticals detected in WWTPs in the northern cities than
the southern ones. The state-of-the-art treatment processes were generally inefficient
in removing pharmaceuticals. Only 14.3% of pharmaceuticals were removed effectively
(mean removal efficiency>70%), while 51.4% had a removal rate of below 30%. The anaerobic/anoxic/oxic
(AAO)-membrane bioreactor (MBR) integrated process and sequencing batch reactor (SBR)
showed better performance than the AAO and oxidation ditch (OD) processes. Ofloxacin,
erythromycin-H2O, clarithromycin, roxithromycin and sulfamethoxazole in WWTP effluents
exhibited a high or medium ecological risk and deserved special attention.