Destruction of PFAS and CWA in Benchscale Supercritical Water Oxidation Reactor

J. Li, S. Moore, C. Austin, B. Pinkard, A. Mamishev, I. Novosselov
University of Washington, Washington, United States

Poster stand number: T103

Keywords: PFAS, supercritical water oxidation, sustainability

Under supercritical conditions, organic compounds and oxygen become fully miscible in water, allowing oxidation to occur in a single fluid phase with excellent transport properties. This work demonstrates the mineralization of PFAS, CWA, and CWA surrogates in a lab-scale SCWO reactor. Fast decomposition rates enable a dramatic reduction of the system's Size, Weight, and Power (SWAP) requirements, and a single-step, continuous process reduces involvement of operator. The first point envisions a portable, skid-mounted system, while the latter focuses on reducing manpower requirements, training, and opportunities for error. Specifically, this work addresses: (1) fundamental chemical kinetic rates for decomposition of recalcitrant species over the range of operating conditions, (2) the fate of potentially toxic intermediates, including gaseous and effluent, (3) the strategies for corrosion control, and (4) the automated process control. The platform was operated for several months and was tuned for the destruction of a wide range of PFAS, demonstrating 99.999% destruction efficiencies. Additionally, the destruction of CWA surrogate (DMMP) was studied, and then the process was used for the destruction of GB and HD agents at the U.S. Army DEVCOM Chemical Biological Center. Complete mineralization (99.99+%) of DMMP, GB, and HD was achieved for all targets.