Formation and fate of perfluoroalkyl acids (PFAAs) in a laboratory-scale urban wastewater system. (1st June 2022)

• Record Type: Journal Article
• Authors: Li, Yijing; Bräunig, Jennifer; Thai, Phong K.; Rebosura, Mario; Mueller, Jochen F.; Yuan, Zhiguo
• Is Part Of: Water research. Volume 216(2022)
• Publication Date: 2022-06-01
• Subjects: Urban wastewater system -- Perfluoroalkyl acids -- Sewer process -- Activated sludge -- Anaerobic digestion; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2022.118295
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Mass balance of 11 PFAAs in a laboratory wastewater system was investigated. Total mass of PFAAs increased by 112% in the system. Mass increase of PFAAs: activated sludge > sewer process > anaerobic digestion. Mass of 11 PFAAs in the effluent was 5 times higher than that in digested sludge. Abstract: The fate and formation of perfluoroalkyl acids (PFAAs) have been investigated during wastewater treatment processes but studies for the entire urban wastewater system comprising the sewage transport and wastewater and sludge treatment processes are scarce. This work performs an integrated assessment of the formation and fate of PFAAs in the urban wastewater system together with their behavior in separate components of the system. To achieve this, PFAAs were monitored over five weeks in a laboratory-scale urban wastewater system comprising sewer reactors, a wastewater treatment reactor, and an anaerobic sludge digester. The system was fed with real domestic wastewater. The total mass of 11 PFAAs flowing out of the laboratory wastewater system significantly ( p < 0.05) increased by 112 ± 14 (mean ± standard error)% compared to that entering the system. Formation of PFAAs was observed in all three biological processes of the system. In anaerobic sewer process, perfluoropentanoic acid (PFPeA), perfluoroheptanoic acid (PFHpA), and perfluorooctane sulfonate (PFOS) exhibited significant formation ( p < 0.05) with the mass flow increased by 79 ± 24%, 109 ± 31%, and 57 ± 17%, respectively. During the wastewater treatment process, perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), and perfluorododecanoic acid (PFDoDA) demonstrated significant increase ( p < 0.05) in their mass flows by 176 ± 56%, 92 ± 21%, and 516 ± 184%, respectively. In contrast, only PFHxA was found to significantly ( p < 0.05) increase by 130 ± 40% during anaerobic digestion process. The total mass of 11 PFAAs discharged through the effluent (201 ± 24 ng day −1 ) was 5 times higher than that through the digested sludge (29 ± 6 ng day −1 ). Graphical abstract: Image, graphical abstract