Plasma-driven Destruction of PFAS in Complex Water Matrices

As evidence linking PFAS exposure to adverse health consequences continues to grow and actionable regulations are expected to be finalized by the end of 2023, the market interest in technologies that are capable of destroying PFAS is higher than ever. Plasmas have been shown to be highly effective at destroying PFAS but still face challenges with scale-up and decomposition of short-chain PFAS. Fourth State is developing a plasma reactor that uses an innovative geometric approach that optimizes the plasma-liquid interface and leverages turbulent flow to destroy both long- and short-chain PFAS without any additives. Thus, the technology represents an environmentally friendly approach to PFAS destruction and has been demonstrated to operate effectively in a range of different wastewaters with no secondary waste streams and at energy costs competitive with competing technologies. The proposed project involves treating landfill leachate using the plasma reactor with the goal of extracting rate constants for PFAS destruction which will be used to inform the scale-up from the laboratory batch reactor to a scalable continuous flow reactor amenable to commercialization. Since the rate constants will be different in leachate compared to groundwaters due to differences in the water matrices, a dedicated study of kinetics in leachate is needed to understand the power and recirculation requirements to reach target treatment levels. In the process, the energy efficiency associated with PFAS destruction will be assessed and compared with competing technologies. Additionally, the water quality evolution throughout the plasma treatment process as well as the impact and fate of co-contaminants will also be elucidated. Such understanding of reactor scaling behavior is a necessary prerequisite for a credible Phase II activity and ultimately commercializing the technology. Furthermore, this project aims to exploit the precipitation induced by plasma treatment, both as a treatment process for removing heavy metals and as an opportunity for recovering resources from waste streams. This project addresses the issue of PFAS treatment in complex water matrices, and thus significantly expands the markets to which this technology may be applied, including groundwaters, industrial wastewaters, and concentrates from separative treatment processes. Identification and mitigation of reactor failure modes will de-risk the technology, making it amenable to adoption. Meanwhile, the issue of scale-up is being addressed by a separate, but parallel and synergistic research activity which will use the rate constants for PFAS destruction to inform the reactor scale-up to throughputs exceeding 50 gallons per minute.