Abstract:
Wastewater treatment plants (WWTPs) have been identified as an important source for release of pharmaceuticals into the environment. There are several studies on occurrence of pharmaceuticals at WWTPs across the globe, but in India, negligible work is done in this domain. In this study, the occurrence and seasonal variation of 10 pharmaceuticals in a 46 MGD capacity WWTP located in western part of India was investigated over a period of one year during three seasons: winter, summer and monsoon. The WWTP was operated based on the lagoon treatment system. A multiresidue method was developed using solid phase extraction (SPE) followed by High-Resolution Liquid Chromatography-Tandem Mass Spectrometry (HR-LC/MS/MS). The yearly average influent concentration of pharmaceuticals at the WWTP was found to be 537 ± 5 μg/L. Seasonal variation of pharmaceuticals in the influent was assessed at this WWTP. The highest concentration of pharmaceuticals was observed in winter (666 ± 3 μg/L), followed by summer (520 ± 3 μg/L), while the concentrations were lowest in the monsoon season (426 ± 9 μg/L). Among the detected pharmaceuticals, the highest concentration was observed for azithromycin (303 ± 4 μg/L) in winter season, levofloxacin (155 ± 2 μg/L) and acetaminophen (148 ± 3 μg/L) in summer season, and azithromycin (177 ± 5 μg/L) in monsoon season, respectively. The removal rate of pharmaceuticals was also compared in the three seasons. For total pharmaceuticals, the removal rate remained same for winter (58 ± 3 %) and summer (57 ± 5 %), whereas the removal rate in the monsoon season was higher (70 ± 1 %). The results of this study illustrate the effectiveness of the currently practised wastewater treatment processes and may also be used for assessment of reusability of treated wastewater. This is the first comprehensive study on occurrence and fate of PPCPs in an Indian WWTP.
