Typical pharmaceuticals in major WWTPs in Beijing, China: Occurrence, load pattern and calculation reliability.

Pharmaceutically active compounds (PhACs) are recognized as one of the most serious emerging micropollutants. Wastewater treatment plants are the major way through which such contaminants enter the environment. Therefore, an appropriate management of PhACs in these facilities can reduce their release into the environment. In particular, a proper sampling methodology is necessary to identify and quantify micropollutants in wastewater. In this study, 37 pharmaceuticals (including 23 antibiotics) are investigated in eight major wastewater treatment plants in Beijing. An optimized sampling methodology is successfully implemented to monitor bihourly variation of the contaminants, thus averting uncertainties derived from conventional sampling methods. In this way, more accurate pharmaceutical load patterns are determined and discussed. Thanks to the synchronous data on pharmaceutical concentration and wastewater flow, we also compare performances of various treatment processes and optimize different calculation methods for removal efficiency.