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Smallwood TJ, Magnuson JK, Thompson JT, Lin AM, Townsend TG. Insights on volatile metals in landfill gas as determined from advanced treatment media. J Hazard Mater 2024; 462:132777. [PMID: 37856961 DOI: 10.1016/j.jhazmat.2023.132777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 10/03/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023]
Abstract
This study analyzed spent activated carbon (AC) from a landfill gas (LFG) treatment system for an expanded suite of lesser studied volatile metals, revealing elevated levels of As and Sb in the LFG, exceeding those previously reported, with minimum average concentrations of 640 µg m-3 and 590 µg m-3, respectively. The annual release of As and Sb through landfill gas was found to be significant, surpassing leachate emissions by an order of magnitude. Extrapolating these findings to all US landfills suggests that the release of As and Sb through landfill gas could be a major, previously overlooked source of these metals in global emission estimates, underscoring the need to include them when developing future inventories. The spent AC was further found to exceed US toxicity limits established for As, classifying it as hazardous waste under US regulations. However, findings suggest that the AC scrubber employed at the landfill effectively prevented substantial releases of As and Sb. This research emphasizes that landfill gas is a primary contributor to environmental release of As and Sb from landfills, even more so than leachate, highlighting the significance of implementing effective LFG treatment measures to mitigate the release of volatile metal emissions.
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Affiliation(s)
- Thomas J Smallwood
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Jordan K Magnuson
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Jake T Thompson
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Ashley M Lin
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA
| | - Timothy G Townsend
- Department of Environmental Engineering Sciences, University of Florida, P. O. Box 116450, Gainesville, FL 32611-6450, USA.
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Smallwood TJ, Robey NM, Liu Y, Bowden JA, Tolaymat TM, Solo-Gabriele HM, Townsend TG. Per- and polyfluoroalkyl substances (PFAS) distribution in landfill gas collection systems: leachate and gas condensate partitioning. J Hazard Mater 2023; 448:130926. [PMID: 36764258 PMCID: PMC10641829 DOI: 10.1016/j.jhazmat.2023.130926] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/06/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
While per- and polyfluoroalkyl substances (PFAS) have been reported extensively in municipal solid waste (MSW) landfill leachate,they have rarely been quantified in landfill gas or in discrete landfill liquids such as landfill gas condensate (LGC), and the potential for PFAS to partition to the condensate has not been reported. LGC and leachate collected from within gas wells known as gas well pump-out (GWP) from three MSW landfills underwent physical-chemical characterization and PFAS analysis to improve understanding of the conditions under which these liquids form and to illuminate PFAS behavior within landfills. LGC was observed to be clear liquid containing ammonia and alkalinity while GWP strongly resembled leachate - dark in color, high in chloride and ammonia. Notably, arsenic and antimony were found in concentrations exceeding regulatory thresholds by over two orders of magnitude in many LGC samples. LGC contained a lower average concentration of ΣPFAS (19,000 ng L) compared to GWP (56,000 ng L); however, LGC contained more diversity of PFAS, with 53 quantified compared to 44 in GWP. LGC contained proportionally more precursor PFAS than GWP, including more semi-volatile PFAS which are rarely measured in water matrices, such as fluorotelomer alcohols and perfluoroalkane sulfonamido ethanols. This study provides the first detailed comparison of these matrices to inform timely leachate management decisions.
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Affiliation(s)
- Thomas J Smallwood
- University of Florida, Department of Environmental Engineering Sciences, College of Engineering, Gainesville, FL 32611, USA
| | - Nicole M Robey
- University of Florida, Department of Environmental Engineering Sciences, College of Engineering, Gainesville, FL 32611, USA
| | - Yalan Liu
- University of Florida, Department of Environmental Engineering Sciences, College of Engineering, Gainesville, FL 32611, USA
| | - John A Bowden
- University of Florida, Department of Environmental Engineering Sciences, College of Engineering, Gainesville, FL 32611, USA; University of Florida, Center for Environmental and Human Toxicology, Department of Physiological Sciences, College of Veterinary Medicine, Gainesville, FL 32610, USA
| | - Thabet M Tolaymat
- US Environmental Protection Agency, Office of Research and Development, Center for Environmental Solutions and Emergency Response, Cincinnati, OH 45268, USA
| | - Helena M Solo-Gabriele
- University of Miami, Department of Chemical, Environmental and Materials Engineering, Coral Gables, FL 33146, USA
| | - Timothy G Townsend
- University of Florida, Department of Environmental Engineering Sciences, College of Engineering, Gainesville, FL 32611, USA.
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de Oliveira FDG, Robey NM, Smallwood TJ, Spreadbury CJ, Townsend TG. Landfill gas as a source of anthropogenic antimony and arsenic release. Chemosphere 2022; 307:135739. [PMID: 35850227 DOI: 10.1016/j.chemosphere.2022.135739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/27/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
Antimony is used extensively in consumer goods, including single use plastic bottles, electronics, textiles and automobile brakes, which are disposed of in landfills at the end of their service lives. As a result, Sb is a constituent of concern in landfill emissions. Previous research has focused on leachate (liquid) and waste incineration flue gas emissions; however, Sb has the potential to volatilize through chemical and microbial processes within a landfill. In this study, iron-amended granular activated carbon was used to adsorb volatile metals directly from gas in a full-scale landfill gas collection system. Metals were quantified using acid digestion and ICP-AES analysis. Antimony concentrations far exceeded those previously reported, at up to 733 μg m-3 (mean: 254 μg m-3). In addition to Sb, As was also measured at high levels compared to previous research, as high as 740 μg m-3 (mean: 178 μg m-3). Using US EPA landfill and landfill gas databases, total Sb emissions via landfill gas are estimated to be approximately 27.3 kg day-1 in the US. Based on other estimates of national and global Sb emissions, this corresponds to approximately 4.5% of total US atmospheric emissions of Sb and 0.42% of global atmospheric emissions. Sb mass release via landfill gas is approximately 3.9 times higher than via leachate emissions. Although gas emissions are higher than expected, the vast majority (99.9%) of Sb present in landfilled MSW remains within the waste mass indefinitely. In addition to these mass release estimates, this experiment suggests that iron-amended activated carbon may offer significant metals removal from LFG, especially in the first months of new well operation.
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Affiliation(s)
- Fernando D G de Oliveira
- Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, PO Box 116450, Gainesville, FL, 32611, USA
| | - Nicole M Robey
- Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, PO Box 116450, Gainesville, FL, 32611, USA
| | - Thomas J Smallwood
- Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, PO Box 116450, Gainesville, FL, 32611, USA
| | - Chad J Spreadbury
- Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, PO Box 116450, Gainesville, FL, 32611, USA
| | - Timothy G Townsend
- Department of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructure and Environment, University of Florida, PO Box 116450, Gainesville, FL, 32611, USA.
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