Removal of personal care products (PCPs) in wastewater and sludge treatment and their occurrence in receiving soils

Abstract

Clean water is one of the main resources for key activities such as agriculture, power generation, and public and industrial supplies. However, once wastewater generated by these activities is released into the environment, it may represent a potential risk to ecosystems and even human health depending on the presence of certain types and levels of contaminants. This study is focused on personal care products (PCPs), a class of contaminants of emerging concern (CECs) which includes commonly used cosmetic and personal hygiene products (e.g., fragrances, UV filters, antimicrobials, surfactants, among others), and their comparison with legacy contaminants such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). We have monitored the concentrations of up to 66 target compounds in influent and effluent wastewater, sludge, and compost samples from a wastewater treatment plant (WWTP) at Jerez de la Frontera (SW Spain) over a 1-year period. Almost half of the target compounds (44%) were frequently detected in influent wastewater samples, with prevalence of synthetic fragrances and higher abundance of UV filters during warmer periods. Due to their relatively poor removal efficiencies (<70%), 30 target compounds were always detected in the final effluent. The highest levels here were observed for an UV filter (octocrylene) and three synthetic fragrances (traseolide, OTNE, and galaxolide), showing maximum concentrations of 4–7 μg L−1 and 12–95 μg g−1 in the dissolved and particulate fractions, respectively. Concentrations of these compounds increased in sludge, being up to 365 μg g−1 for some fragrances and showing negligible decrease after anaerobic digestion. Windrow composting of this sludge, however, resulted in an efficient removal (up to 100%) for most analytes. On the other hand, levels between <1 and 651 ng g−1 were measured in soils columns (0–150 cm) at the WWTP gardens irrigated with effluent wastewater. The occurrence of PCPs in these soils seemed to be heavily influenced by temperature, as maximum concentrations were measured in colder months, indicating a higher rate of microbial activity degradation and/or volatilization during warmer months.