Occurrence and removal of ibuprofen and its metabolites in full-scale constructed wetlands treating municipal wastewater

Ibuprofen (IBU) and its major metabolites, hydroxyibuprofen (OH-IBU) and carboxyibuprofen (CA-IBU) were monitored from November 2015 to March 2017 at four full-scale constructed wetlands with horizontal sub-surface flow treating municipal wastewater in the Czech Republic. During the seven sampling campaigns, all three compounds were identified in high concentrations in the inflowing raw wastewater. The average inflow concentrations of IBU, OH-IBU and CA-IBU amounted to 14.6, 18.3 and 36.4 mu g l(-1). The ratio between IBU, OH-IBU and CA-IBU is in agreement with the previously published results indicating that the ibuprofen metabolites occur in higher concentration in the raw wastewater than the parent compound with CA-IBU exhibiting the highest concentrations. The outflow concentrations off studied compounds decreased and removal amounted to 44.7%, 29.3% and 47.5% for IBU, OH-IBU and CA-IBU, respectively. The results are in line with general fact that ibuprofen and its metabolites are not removed with high efficiency in anoxic or anaerobic conditions and that OH-IBU is the least removed compound. The areal loadings of IBU, OH-IBU and CA-IBU averaged 0.425, 0.574 and 0.999 mg m(-2) d(-1), respectively. The annual loads of all forms of ibuprofen varied between 458 and 958 g year(-1) among four studies constructed wetlands.