Grantee Research Project Results
Occurrence, fate, transport, and treatment of per- and polyfluoroalkyl substances (PFASs) in landfill leachate
EPA Grant Number: R839670Title: Occurrence, fate, transport, and treatment of per- and polyfluoroalkyl substances (PFASs) in landfill leachate
Investigators: Guelfo, Jennifer
Institution: Texas Tech University
EPA Project Officer: Hahn, Intaek
Project Period: August 1, 2019 through July 31, 2022 (Extended to July 31, 2024)
Project Amount: $500,000
RFA: Practical Methods to Analyze and Treat Emerging Contaminants (PFAS) in Solid Waste, Landfills, Wastewater/Leachates, Soils, and Groundwater to Protect Human Health and the Environment (2018) RFA Text | Recipients Lists
Research Category: Drinking Water , Water Quality , Human Health , PFAS Treatment , Water
Objective:
An estimated 61.1 million m3yr-1 of leachate is generated in the United States. Studies suggest that most leachates contain per- and polyfluoroalkyl substances (PFASs) that may pose a risk to human health and/or the environment following release of raw or treated leachate. This project has three primary objectives: 1) optimize strategies for analysis of total PFAS composition and concentrations in field-collected landfill leachate using a combination of analytical techniques; 2) assess sorption, desorption, and diffusion of a select set of PFASs in representative flexible membrane and clay liner materials and evaluate impacts of solution chemistry on these processes; and 3) evaluate the impacts of leachate conditions on the rate and efficacy of total PFAS degradation using ultrasound treatment and determine optimal reactor configuration and operational parameters based on landfill conditions and treatment goals.
This project will evaluate the following hypotheses: 1) landfill leachate will contain unique mixtures of perfluoroalkyl acids (PFAAs), precursors, and newly identified PFASs; 2) analysis using liquid chromatography high resolution mass spectrometry (LC-HRMS) plus the total oxidizable precursor assay (TOP), total organic fluorine (TOF)-combustion ion chromatography (CIC), and extractable organic fluorine (EOF)-CIC will each yield different estimates of total PFASs in leachate; 3) the diffusion of PFASs through flexible membrane liners (FMLs) will be dependent on both compound structure and solution chemistry; 4) PFAS diffusion through the clay liner will be greatest for anionic PFASs and in materials with low organic carbon (foc) and lowest for cationic and zwitterionic PFASs and in materials with high foc; 5) PFAS retention in the clay liner will be influenced by solution chemistry; 6) ultrasonic treatment will be capable of degrading total PFASs in landfill leachate with a variety of solution chemistries; and 7) sonolysis will have application towards leachate treatment in multiple configurations.
Approach:
The proposed hypotheses will be evaluated through in-depth characterization of landfill leachate samples using multiple analytical techniques (Hypothesis 1-2), laboratory investigations of PFAS fate and transport (Hypotheses 3-5), and bench-scale studies of PFAS treatment via ultrasonic degradation (Hypothesis 6-7). Analytical techniques include targeted and non-targeted analysis using LC-HRMS, quantification of oxidizable precursors using TOP, and assessment of organic fluorine using TOF- and EOF-CIC, which will be used to understand the composition and concentration of total PFAS in leachate. Sorption and desorption of PFASs in leachate through the FML and clay liner will be studied using batch experiments and diffusion studied using two-chamber diffusion cells. Samples from these experiments will be analyzed by LC-HRMS to assess behavior of a broad suite of PFAS. Data from these experiments will be compiled into a 1-dimensional model of transport in a composite liner system. Finally, treatment of PFAS will be studied using an ultrasonic reactor (InSRT). The InSRT reactor will be operated in batch mode using synthetic leachate to determine optimal reactor conditions and then the optimized configuration will be applied to field-collected leachate in both batch and flow-through modes.
Expected Results:
The proposed research will address areas one (occurrence/characterization), two (fate and transport), and three (control/treatment) of the funding opportunity announcement. The overarching benefit of this work is assessment and mitigation of the risks associated with PFASs in landfill leachate to support development of regulations and design criteria that promote safe disposal of PFAS-containing wastes. Other benefits include occurrence data to support identification of environmentally-relevant PFASs, tools to estimate PFAS mass flux from landfills, and development of treatment technologies that can be extended to multiple sources of PFAS release.
Publications and Presentations:
Publications have been submitted on this project: View all 13 publications for this projectJournal Articles:
Journal Articles have been submitted on this project: View all 3 journal articles for this projectSupplemental Keywords:
adsorption, absorption, chemical transport, persistent organic pollutants, remediation, environmental chemistry, environmental engineering, landfill design, solid waste managementProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.