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Sørmo E, Lade CBM, Zhang J, Asimakopoulos AG, Åsli GW, Hubert M, Goranov AI, Arp HPH, Cornelissen G. Stabilization of PFAS-contaminated soil with sewage sludge- and wood-based biochar sorbents. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 922:170971. [PMID: 38408660 DOI: 10.1016/j.scitotenv.2024.170971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 02/12/2024] [Accepted: 02/12/2024] [Indexed: 02/28/2024]
Abstract
Sustainable and effective remediation technologies for the treatment of soil contaminated with per- and polyfluoroalkyl substances (PFAS) are greatly needed. This study investigated the effects of waste-based biochars on the leaching of PFAS from a sandy soil with a low total organic carbon content (TOC) of 0.57 ± 0.04 % impacted by PFAS from aqueous film forming foam (AFFF) dispersed at a former fire-fighting facility. Six different biochars (pyrolyzed at 700-900 °C) were tested, made from clean wood chips (CWC), waste timber (WT), activated waste timber (aWT), two digested sewage sludges (DSS-1 and DSS-2) and de-watered raw sewage sludge (DWSS). Up-flow column percolation tests (15 days and 16 pore volume replacements) with 1 % biochar indicated that the dominant congener in the soil, perfluorooctane sulphonic acid (PFOS) was retained best by the aWT biochar with a 99.9 % reduction in the leachate concentration, followed by sludge-based DWSS (98.9 %) and DSS-2 and DSS-1 (97.8 % and 91.6 %, respectively). The non-activated wood-based biochars (CWC and WT) on the other hand, reduced leaching by <42.4 %. Extrapolating this to field conditions, 90 % leaching of PFOS would occur after 15 y for unamended soil, and after 1200 y and 12,000 y, respectively, for soil amended with 1 % DWSS-amended and aWT biochar. The high effectiveness of aWT and the three sludge-based biochars in reducing PFAS leaching from the soil was attributed largely to high porosity in a pore size range (>1.5 nm) that can accommodate the large PFAS molecules (>1.02-2.20 nm) combined with a high affinity to the biochar matrix. Other factors like anionic exchange capacity could play a contributing role. Sorbent effectiveness was better for long-chain than for short-chain PFAS, due to weaker, apolar interactions between the biochar and the latter's shorter hydrophobic CF2-tails. The findings were the first to demonstrate that locally sourced activated wood-waste biochars and non-activated sewage sludge biochars could be suitable sorbents for the ex situ stabilization and in situ remediation of PFAS-contaminated soil, bringing this technology one step closer to full-scale field testing.
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Affiliation(s)
- Erlend Sørmo
- Norwegian Geotechnical Institute (NGI), 0484 Oslo, Norway; Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), 1430 Ås, Norway
| | - Clara Benedikte Mader Lade
- Norwegian Geotechnical Institute (NGI), 0484 Oslo, Norway; Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), 1430 Ås, Norway
| | - Junjie Zhang
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7024 Trondheim, Norway
| | | | - Geir Wold Åsli
- Norwegian Geotechnical Institute (NGI), 0484 Oslo, Norway
| | - Michel Hubert
- Norwegian Geotechnical Institute (NGI), 0484 Oslo, Norway
| | - Aleksandar I Goranov
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA, USA
| | - Hans Peter H Arp
- Norwegian Geotechnical Institute (NGI), 0484 Oslo, Norway; Department of Chemistry, Norwegian University of Science and Technology (NTNU), 7024 Trondheim, Norway
| | - Gerard Cornelissen
- Norwegian Geotechnical Institute (NGI), 0484 Oslo, Norway; Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), 1430 Ås, Norway.
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Vistnes H, Sossalla NA, Asimakopoulos AG, Meyn T. Occurrence of traffic related trace elements and organic micropollutants in tunnel wash water. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133498. [PMID: 38232556 DOI: 10.1016/j.jhazmat.2024.133498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/19/2024]
Abstract
Substantially polluted tunnel wash water (TWW) is produced during road tunnel maintenance. Previous literature has reported the presence of trace elements and polycyclic aromatic hydrocarbons (PAHs). However, it was hypothesized that other organic pollutants are present, and more knowledge is needed to prevent environmental harm. This study reveals for the first time the presence of four short- and 17 long-chained per- and polyfluoroalkyl substances (PFASs), three benzothiazoles (BTHs), six benzotriazoles (BTRs), four bisphenols, and four benzophenones in TWW from a Norwegian road tunnel over a period of three years. Concentrations of PAHs, PFASs, BTHs, and BTRs were higher than previously reported in e.g., road runoff and municipal wastewater. Trace elements and PAHs were largely particulate matter associated, while PFASs, BTHs, BTRs, bisphenols, and benzophenones were predominantly dissolved. 26 of the determined contaminants were classified as persistent, mobile, and toxic (PMT) and are of special concern. It was recommended that regulations for TWW quality should be expanded to include PMT contaminants (such as PFPeA, PFBS, BTR, and 4-OH-BzP) and markers of pollution (like 2-M-BTH, 2-OH-BTH, and 2-S-BTH from tire wear particles). These findings highlight the need to treat TWW before discharge into the environment, addressing both, particulate matter associated and dissolved contaminants.
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Affiliation(s)
- Hanne Vistnes
- Department of Civil and Environmental Engineering, Norwegian University of Science and Technology (NTNU), S. P. Andersens veg 5, 7031 Trondheim, Norway
| | - Nadine A Sossalla
- Department of Civil and Environmental Engineering, Norwegian University of Science and Technology (NTNU), S. P. Andersens veg 5, 7031 Trondheim, Norway
| | - Alexandros G Asimakopoulos
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, 7034 Trondheim, Norway
| | - Thomas Meyn
- Department of Civil and Environmental Engineering, Norwegian University of Science and Technology (NTNU), S. P. Andersens veg 5, 7031 Trondheim, Norway.
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Sadia M, Beut LB, Pranić M, Wezel AP, Laak TL. Sorption of per- and poly-fluoroalkyl substances and their precursors on activated carbon under realistic drinking water conditions: Insights into sorbent variability and PFAS structural effects. Heliyon 2024; 10:e25130. [PMID: 38317999 PMCID: PMC10839585 DOI: 10.1016/j.heliyon.2024.e25130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 12/17/2023] [Accepted: 01/21/2024] [Indexed: 02/07/2024] Open
Abstract
Recent stringent drinking water quality standards create challenges for water utilities to meet these standards. Advanced treatment techniques will have to be applied on many drinking water production locations to meet these quality standards. This study investigated the sorption of per- and polyfluorinated-alkyl substances (PFAS) onto granular activated carbon (GAC). The study was performed at environmentally relevant PFAS concentrations and a realistic water-to-GAC ratio, providing a realism often overlooked in existing studies. Three different forms of GAC were evaluated, differing in micropore and mesopore structures. Tap water spiked with 5 ng/L of each of 31 PFAS was used in the sorption experiments, i.e. perfluorocarboxylic acids (C4-C12), perfluorosulfonic acids (PFSA, C5-C10) including linear and branched isomers, and three groups of PFAS precursors (per-/polyfluoroalkyl ether acids, sulfonamides, and sulfonamide acetic acids). The three studied GAC did not exhibit distinct differences in PFAS sorption. The removal of PFAS was below 50 % for most studied PFAS, except for the short-chain PFAS precursors. Sorption was affected by both the carbon chain length and functional groups for PFAS, while this was not observed for PFAS precursors. The presence of ether linkages and sulfonamide groups notably enhanced sorption. Linear and branched PFSA demonstrated similar sorption behavior, whereas branched isomers of the sulfonamide acetic acid precursors exhibited significantly higher sorption. This indicates that sorption was determined by both hydrophobic and electrostatic interactions. Given the relatively low PFAS removal by GAC under environmentally relevant test conditions, further improvements in sorbents are required to ensure that PFAS concentrations in produced drinking water comply with drinking water standards.
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Affiliation(s)
- Mohammad Sadia
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, the Netherlands
| | - Lola Beltrán Beut
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, the Netherlands
| | - Marko Pranić
- Environmental Technology, Wageningen University, Bornse Weilanden 9, 6708WG, Wageningen, the Netherlands
| | - Annemarie P.van Wezel
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, the Netherlands
| | - Thomas L.ter Laak
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, the Netherlands
- KWR Water Research Institute, Groningenhaven 7, 3430BB Nieuwegein, the Netherlands
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Hubert M, Meyn T, Hansen MC, Hale SE, Arp HPH. Per- and polyfluoroalkyl substance (PFAS) removal from soil washing water by coagulation and flocculation. WATER RESEARCH 2024; 249:120888. [PMID: 38039821 DOI: 10.1016/j.watres.2023.120888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/09/2023] [Accepted: 11/15/2023] [Indexed: 12/03/2023]
Abstract
Soil washing is currently attracting attention as a promising remediation strategy for land contaminated with per- and polyfluoroalkyl substances (PFAS). In the soil washing process, the contaminant is transferred from the soil into the liquid phase, producing a PFAS contaminated process water. One way to treat such process water is to use coagulation and flocculation; however, few studies are available on the performance of coagulation and flocculation for removing PFAS from such process water. This study evaluated 6 coagulants and flocculants (polyaluminium chloride (PACl), zirconium oxychloride octahydrate, cationic and anionic polyacrylamide, Polyclay 685 and Perfluor Ad®), for the treatment of a proxy PFAS contaminated washing water, spiked with PFAS concentrations found at typical Aqueous Film Forming Foam (AFFF) contaminated sites. PFAS removal efficiencies (at constant pH) varied greatly depending on the coagulants and flocculants, as well as the dosage used and the targeted PFAS. All tested coagulants and flocculants reduced the turbidity by >95%, depending on the dosage. Perfluor Ad®, a specially designed coagulant, showed the highest removal efficiency for all longer chain (>99%) and shorter chain PFAS (>68%). The cationic polyacrylamide polymer removed longer chain PFAS up to an average of 80%, whereas average shorter chain PFAS removal was lower (<30%). The two metal-based coagulants tested, PACl and zirconium, removed longer chain PFAS by up to an average of 61% and shorter chain PFAS up to 48%. Polyclay 685, a mixture of powdered activated carbon (PAC) and aluminium sulphate, removed longer chain PFAS by 90% and shorter chain PFAS on average by 76%, when very high dosages of the coagulant were used (2,000 mg/L). PFAS removal efficiencies correlated with chain length and headgroup. Shorter chain PFAS removal was dependent on electrostatic interaction with the precipitating flocs, whereas for longer chain PFAS, hydrophobic interactions between apolar functional groups and flocs created by the coagulant/flocculant, dissolved organic matter and suspended solids played a major role. The results of this study showed that by selecting the most efficient coagulant and aqueous conditions, a greater amount of PFAS can be removed from process waters in soil washing facilities, and thus included as part of various treatment trains.
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Affiliation(s)
- Michel Hubert
- Norwegian Geotechnical Institute (NGI), NO-0806 Oslo, Norway; Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
| | - Thomas Meyn
- Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
| | | | - Sarah E Hale
- Norwegian Geotechnical Institute (NGI), NO-0806 Oslo, Norway; DVGW-Technologiezentrum Wasser, 76139 Karsruhe, Germany
| | - Hans Peter H Arp
- Norwegian Geotechnical Institute (NGI), NO-0806 Oslo, Norway; Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
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