The significance of fluorinated compound chain length, treatment technology, and influent composition on per- and polyfluoroalkyl substances removal in worldwide wastewater treatment plants.

Wastewater treatment plants (WWTPs) are deemed major conveyors and point sources of per- and polyfluoroalkyl substances (PFAS) to the environment. This statistical meta-analysis of existing literature from the past 15 years focused on the significance of treatment type for PFAS removal efficiencies and the influence of PFAS sources (domestic vs. industrial) on their removal. Different sampling events, WWTPs across the world, different treatment technologies, configurations, and processes, as well as different PFAS classes and compounds were considered. This study evaluated 13 PFAS analyzed predominantly in 161 WWTPs across the world. The statistical test results revealed that these 13 frequently detected and reported PFAS can be divided into four groups based on their behavior during wastewater treatment, namely (1) C6-10 perfluorocarboxylic acids (PFCAs), (2) C4,5,11,12 PFCAs, (3) C4,6,8 perfluoroalkane sulfonic acids (PFSAs), and (4) C10 PFSA. In this study, biological treatments such as (1) membrane bioreactors, (2) combination of two or more biological treatments, and (3) biofilm processes revealed the highest PFAS removals, although the addition of a tertiary treatment actually had a nonbeneficial effect on PFAS removal. Moreover, a strong statistical correlation was observed between industrial wastewater sources and the presence of high influent PFAS concentrations in the receiving WWTPs. This indicates that industrial sources were the main contributors of the PFAS load in the analyzed WWTPs. Integr Environ Assess Manag 2024;20:59-69. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Impact of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) on secondary sludge microorganisms: removal, potential toxicity, and their implications on existing wastewater treatment regulations in Canada.

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are two of the most commonly researched per- and polyfluoroalkyl substances (PFAS). Globally, many long-chain PFAS compounds including PFOS and PFOA are highly regulated and, in some countries, PFAS use in commercial products is strictly prohibited. Despite the legal regulation of these 'forever chemicals' under the Canadian Environmental Protection Act, PFOA and PFOS compounds are still found in high concentrations in discharges from wastewater treatment plants, both from liquid and sludge streams. Yet, their potential impact on wastewater treatment effectiveness remains poorly understood. The findings of this research show that: (1) PFOS and PFOA might be hindering the overall outcome treatment performance - calling into question the efficacy of Canada's existing wastewater treatment regulatory standard (Wastewater Systems Effluent Regulations, SOR/2012-139), and (2) specific microorganisms from the Thiobacillus and Pseudomonas genera seem capable of adsorbing PFOS and PFOA onto their cell wall and even degrading the chemicals, but it is unclear as to what extent degradation occurs. The results also raise questions whether existing wastewater regulations should be expanded to include the detection and monitoring of PFAS, as well as the establishment of a regulatory wastewater treatment plant discharge standard for PFAS that is protective of human and ecological health.