Full-scale studies are closer to reality than lab-scale ones: Tertiary treatment constructed wetlands maintain robust removal capability for pharmaceuticals and personal care products in cold weather conditions.

In contrast to previous lab-scale studies, full-scale studies show that low temperatures do not significantly hinder pharmaceutical and personal care product (PPCP) removal in tertiary treatment constructed wetland (CW) systems. This study investigated PPCP removal pathways (substrate adsorption, plant uptake, microbial degradation) in two full-scale CWs, highlighting the differences between full-scale and lab-scale study outcomes. Results demonstrated that low temperatures did not adversely affect PPCP removal in full-scale CWs. Substrate adsorption was minimally impacted at a relevant concentration of 100 ng/L, unlike lab-scale studies with typically higher concentrations (1 mg/L). Plant uptake was not affected, as mature plants in CWs exhibited a lower PPCP uptake capacity compared to seedlings in lab-scale studies. Furthermore, low temperatures did not reduce microbial biodegradation performance. However, low temperatures increased dissolved oxygen concentrations in the influent, supporting aerobic microbial activity. These findings emphasize the value of full-scale CWs for stable PPCP removal under low-temperature conditions.