Destroying PFAS with Foam Fractionation and SCWO: A Practical Experience

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been widely used in various industries and products, such as firefighting foams, non-stick coatings, and textiles. Due to their high stability and resistance to degradation, PFAS can persist in the environment and accumulate in living organisms, posing potential risks to ecological and human health. Therefore, there is an urgent need for effective and efficient methods to remove PFAS from different sources of contamination, such as industrial wastewater, landfill leachate, and Aqueous Film Forming Foam (AFFF). This presentation will introduce and demonstrate a novel approach that combines two established technologies, foam fractionation (FF) and supercritical water oxidation (SCWO), to achieve the concentration and destruction of PFAS from various waste streams. FF is a separation technique that uses air bubbles to capture and enrich PFAS from dilute solutions, resulting in a concentrated PFAS-rich foam. SCWO is a thermochemical process that uses water at high temperature and pressure to oxidize organic compounds, such as PFAS, into harmless products, such as carbon dioxide, water, and salts. By applying FF and SCWO in tandem, PFAS can be effectively removed from contaminated water, leaving behind PFAS-free water that can be safely discharged or reused. The main objective of this presentation is to share the practical experience and results of operating a commercial-scale SCWO unit that has been treating PFAS concentrate from various sources. The presentation will provide analytical data and performance indicators from the treatment of PFAS concentrate derived from raw leachate and industrial wastewater that have been pre-treated with FF. Moreover, the presentation will discuss the process and outcomes of treating AFFF concentrate and rinsate that have been generated from fluorinated foam replacement projects. A key aspect to be highlighted is the benefits and challenges of the integrated FF and SCWO approach, covering design considerations, operational conditions, and field outcomes from full-scale implementation. Attendees will also learn about the prerequisites and steps for field deployment and the regulatory compliance issues related to air and water emissions. The following are the learning objectives of this presentation: 1. To gain an overview of the capabilities and readiness of FF and SCWO technologies for treating PFAS-impacted waste streams. 2. To learn about the best practices and strategies for working with state and municipal regulators to ensure compliance with air and water quality standards. 3. To acquire valuable lessons and insights from the deployment, commissioning, and ongoing operation and optimization of a full-scale SCWO unit.