Dr. Raj Melkote, Ph.D.

Supercritical Water Oxidation for Permanent Destruction of PFAS in Stockpiled AFFF

Dr. Raj Melkote, PhD., Chief Technology, Officer 374Water Inc.

The use of firefighting foams for training, calibration activities, and emergency response is essential, but increased attention on the unintentional release of per- and polyfluoroalkyl substances (PFAS) are changing which types of foams are used. With numerous bans on the discharge of foam into the ground, storm drain, or sewer systems and the transition away from aqueous film-forming foams (AFFF) there will be increasing volumes of stockpiled AFFF. Safely storing the stockpiles on site is only a short-term solution as, amongst other factors, upcoming RCRA definitions of hazardous waste that may include PFAS jeopardize this practice. These warrant planning for the disposal of AFFF stockpiles.  Current techniques included in EPA’s 2024 Version 2 Interim Guidance document are thermal treatment, landfills, and underground injection. The guidance also presents EPA’s PFAS Innovative Treatment Team (PITT) evaluations of emerging technologies including electrochemical oxidation, mechanochemical degradation, pyrolysis, gasification, and supercritical water oxidation (SCWO).  This talk will equip the audience with the data and considerations needed to start planning for safe cost-effective disposal, even in the face of new regulations. Firstly, the concept of “concentrate and destroy” will be used to categorize interim and emerging technologies. A brief overview of how each technology works to concentrate or destroy hazardous compounds in AFFF will be given to facilitate selection of methods capable of achieving the desired treatment efficiency. The focus will then shift to a comparison of the technology readiness level, cost/funding mechanisms, and potential benefits of the emerging technologies including electrochemical oxidation, mechanochemical degradation, pyrolysis, gasification, and supercritical water oxidation (SCWO). The main takeaway of the talk is to emphasize the importance of keeping costs down, ensuring compliance, and advancing the industry toward sustainable waste management practices. 

Raj Melkote is currently Chief Technology Officer for 374Water, a pioneering growth company in the waste destruction space, whose mission is to destroy organic wastes including “forever chemicals” (PFAS) through a novel supercritical water oxidation process.

Melkote is a seasoned R&D / Engineering executive with a track record of introducing and commercializing innovative new industrial technology products across a wide range of industries. Prior to joining 374Water, Melkote was Chief Technology Officer at BayoTech Hydrogen, providing modular, scalable, and rapidly deployable hydrogen generation, transport, storage, and fueling solutions. In that role he led innovation, testing, design, and continuous improvement of BayoTech processes. Previously he worked for Edwards Vacuum where he introduced machine learning to develop predictive diagnostics around pump failures and spearheaded the XVS cryopump platform. Melkote has also held leadership, engineering, and R&D roles with Brooks Automation, Honeywell, United Technologies, and General Electric.  Melkote received his PhD from the University of Minnesota and a Bachelor of Science degree from Purdue University, both in chemical engineering.