Collaborative Research: ERASE-PFAS: Remediation of Per- and Polyfluoroalkyl Substances in Wastewater using Anaerobic Membrane Bioreactors

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Per- and polyfluoroalkyl substances (PFASs) are used in many consumer and industrial products. PFASs have been found in domestic drinking water systems and have been identified in ecosystems on a global basis. PFASs are highly persistent in the environment, and as such have been called ‘forever chemicals.’ Because PFASs are toxic to humans and wildlife, it is important to find efficient ways to eliminate these chemicals from water supplies. The goal of this research is to address this need through the development of anaerobic membrane bioreactors (AnMBRs) that rely on both bacteria and membranes to remove and destroy PFASs from water. This goal will be achieved through a multiphase research program to develop microbial cultures that transform PFAS using novel molecular biological approaches, characterize the PFAS transformation process before and after treatment, and assess the reactivity of end products using state-of-the-science approaches. Successful completion of this research will allow us to better understand how bacteria degrade PFASs and determine how degradation affects the toxicity of these products. Societal benefits include potential development of technology to address the urgent national need for low cost, effective PFAS treatment. Additional benefits include increasing scientific literacy and STEM diversity through outreach, recruitment, and training.The widespread use and extreme stability of PFASs have resulted in their ubiquitous occurrence in the environment. The recalcitrance of PFASs to biodegradation resulting from the inertness of carbon-fluorine bonds is poorly understood. However, reductive defluorination is thermodynamically favorable under reducing conditions, a puzzling finding that warrants further exploration using emerging chemical and molecular biotechnological tools. This project addresses this need through a multi-stage investigation of the biodegradation of PFASs in AnMBRs. AnMBRs combine anaerobic treatment with membrane separation, providing low-energy intensive biological treatment. The overall goal of this project is to develop a set of tools leading to a better understanding of PFAS biotreatment. The specific objectives designed to achieve this goal are to: i) demonstrate reductive defluorination of PFASs in AnMBRs and identify defluorinating microbial populations using emulsion, paired isolation, and concatenation (epic)PCR to link phylogenetic genes with dehalogenation genes at a cellular level; ii) characterize biotransformation products and assess degradation efficiency using high resolution liquid chromatography/mass spectrometry and 19F nuclear magnetic resonance spectroscopy; and iii) systematically evaluate biological activity of PFAS mixtures in mammalian cell lines using an integrated transcriptomics and metabolomics approach. Successful completion of this research holds strong potential to transform our knowledge of water treatment systems for legacy and emerging PFASs. Such information can lead to efficient biological treatment alternatives for PFAS, addressing a critical national need. Broader scientific and societal impacts include the potential for a paradigm shift in current practices for establishing PFAS health advisories should evidence of synergistic interactions in complex PFAS mixtures be established.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.