Occurrence and removal of pharmaceutical and personal care products using subsurface horizontal flow constructed wetlands

Abstract

A significant number of emerging pollutants resulting from point source and diffuse pollution are present in the aquatic environment. These are chemicals that are not commonly monitored, but have the potential to cause adverse effects on human and ecological health. One form of emerging pollutants, pharmaceutical and personal care products (PPCPs), are becoming a serious problem in the discharge of domestic wastewater. Therefore, the aim of this study was to determine their occurrence in wastewater and surface waters, and to evaluate the efficiency of subsurface horizontal flow constructed wetlands (planted in polyculture and unplanted), in removing two pharmaceuticals: carbamazepine (Cbz) and sildenafil (Sil); and a personal care product: methylparaben (Mp), present in domestic wastewater. The mixed PPCPs were added to wetlands, at nominal concentrations of 200 μg / L for each compound. The working flow of the reactors was 15 mL / min and the hydraulic retention time was three days. The physicochemical parameters evaluated were: organic load, dissolved oxygen, temperature, conductivity, redox potential, dissolved solids, pH and PPCPs concentration. The presence of the three compounds became evident in all sampled sites, with concentrations of up to 10.66 μg / L, 7.24 μg / L and 2.64 μg / L for Cbz, Mp and Sil, respectively. In planted wetlands, removal efficiencies of up to 97% were achieved for Sil, while in the unplanted these were 30% lower. Removal efficiencies greater than 97% were achieved for Mp, however, for Cbz they were less than 10%, evaluated in both treatments. The average removal efficiency for organic load was 95%. It was determined that constructed wetlands can efficiently remove simple molecular structure compounds such as Mp, and complex structures such as Sil. However, Cbz remained as a recalcitrant contaminant.