Elimination of mixed ibuprofen and paracetamol from spiked domestic wastewater via a pilot continuous aerated sub-surface constructed wetland system

Abstract

In this study, we proposed three vegetated constructed wetlands (CWs) together with a non-vegetated CW acting as a control in a continuous sub-surface flow system (CSSFS) designed for the remediation of mixed pharmaceuticals (ibuprofen and paracetamol with concentrations of 600 and 60 μg/L, respectively) spiked in domestic wastewater and operated at three different hydraulic retention times (HRT) for 3, 4, and 5 days. The CWs were vegetated with Scirpus grossus (20 plants per m2) and supplied with a 2.0 L/min constant aeration rate for 21 days. The main results revealed that the highest removals for ibuprofen and paracetamol from contaminated wastewater were 99 and 94 %, respectively, for CW at HRT of 5 days, and 89 and 66 % removal of ibuprofen and paracetamol, respectively, for CW at HRT of 3 days. The bacteria population in the rhizosphere was believed to assist this remediation, since a system with higher colony forming units had degraded higher ibuprofen and paracetamol (CFU in CW with HRT of 5 days was significantly higher at p < 0.05 than HRT of 3 days). While the lowest removal occurred in CW with HRT of 5 days, without the existence of vegetation (54 % for ibuprofen and 63 % for paracetamol), plants had performed a significant role in ibuprofen and paracetamol removal from wastewater. The symbiotic effects of bacteria and plants for biodegradation of ibuprofen and paracetamol would be the key strength of the present study.