Overview of Hydrothermal Alkaline Liquid Treatment

Hydrothermal Alkaline Treatment (HALT) is presented as a subcritical water-based PFAS destruction technology operating at 300–350°C, approximately 3,000 psi, and pH greater than 14 using sodium hydroxide. Originally developed under SERDP funding at Colorado School of Mines, the process achieves defluorination of recalcitrant PFAS compounds under moderate supercritical conditions. The technology represents an emerging non-incineration destruction pathway applicable to concentrated PFAS streams from membrane reject and ion exchange regeneration.