Destruction of perfluoro- or polyfluoro-alkyl substances

A method of destroying one or more perfluoro- or polyfluoro-alkyl substances (PFAS), the method comprising:

• electrolytically treating an aqueous composition in an electrochemical cell, wherein the aqueous composition has a pH of 1 to 3.5 and comprises the one or more PFAS, to form an electrolytically-treated aqueous composition, wherein the electrolytically-treated aqueous composition has a concentration of the one or more PFAS that is lower than a concentration of the one or more PFAS in the aqueous composition;
• aerating the electrolytically-treated aqueous composition to form a foam thereon;
• separating the foam from the electrolytically-treated aqueous composition to form a concentrate and a clarified aqueous composition, wherein the clarified aqueous composition has a concentration of the one or more PFAS that is lower than a concentration of the one or more PFAS in the concentrate;
• and
• electrolytically treating the concentrate in the electrochemical cell.