PFAS Destruction in High Strength Waste Streams: A Case Study on Low Energy EOx
Elisabeth Christ – Aclarity
With recent action by the USEPA and individual states, stricter regulation of poly- and perfluorinated alkyl substances (PFAS) in water and solids wastes will change the way that the water industry has dealt with organic contaminants in the past. Typically, regulated organic contaminants have been controlled through the use of oxidation, e.g., ozonation or chlorination, or by adsorption onto activated carbon, followed by high temperature regeneration. Because of the chemical and thermal stability of PFAS compounds, however, these approaches will not work. It has been shown that even the strongest oxidant commonly used in water treatment, hydroxyl radicals, cannot degrade these compounds. It has also been shown that some PFAS is not destroyed by thermal regeneration of activated carbon, even with an afterburner. Several states have banned the incineration of PFAS-containing wastes.These circumstances have led the industry to search for technologies capable of destroying PFAS by breaking carbon-fluorine bonds, among the strongest known in organic chemistry. Among these destructive technologies are supercritical water oxidation (SCWO), hydrothermal alkaline treatment (HALT), plasma reactors, and electrochemical oxidation (EOx).To date, these technologies have been studied at relatively small scales, and are not economic for treating the millions of gallons per day flows for water treatment plants. However, when coupled with concentration technologies such as high pressure membranes, regenerable ion exchange, or foam fractionation, the technologies can be viable for use in municipal water treatment.This presentation will show results from bench and pilot scale testing of Aclarity’s EOx system treating multiple high strength wastes including reverse osmosis brine, raw landfill leachate, ion exchange brines and foam fractionate. In addition to PFAS destruction data, transformation byproducts will be addressed. Economic data demonstrating viability at larger scales will also be presented.
