Systems and methods for thermal destruction of undesired substances by smoldering combustion

Abstract

Porous media containing undesired substances, e.g., perfluoroalkylated substances, are treated by mixing the porous media with a solid fuel comprising organic material. The mixture is heated to 200° C. to 400° C. to initiate smoldering combustion and an oxidizer gas is forced through the heated mixture such that the smoldering combustion is self-sustaining until the mixture reaches a PFAS destructive temperature and the perfluoroalkylated substances are thermally destroyed. A system is provided for conducting the treatment. The system includes a source of wax, wood chips, sawdust, tire scraps, waste rubber compounds, coal, granular activated carbon, solid fat, and combinations thereof as solid fuel. A mixer is provided for mixing the porous media with the solid fuel. An ignition system including static heating elements and a gas blower are provided for forcing heated oxidizer gas through the mixture such that self-sustaining smoldering combustion of the mixture is initiated and sustained.

What is claimed is: 
     
         1 . A method for treating porous media containing an undesired substance, comprising:
 a. adding a solid fuel comprising organic material to the porous media containing the undesired substance to form a mixture that is capable of reaching an undesired substance destructive temperature of at least 800° C., wherein the mixture comprises from 1 to 5% of the solid fuel by vol;   b. heating a portion of the mixture to 200° C. to 400° C. to form a heated mixture and to initiate smoldering combustion of the heated mixture;   c. initiating a flow of an oxidizer gas through a portion of the heated mixture and controlling the flow at a rate such that the smoldering combustion of the heated mixture is self-sustaining; and   d. continuing the self-sustaining smoldering combustion of the mixture until the mixture reaches the undesired substance destructive temperature of at least 800° C.;
 wherein the porous media comprises soil and the undesired substance comprises a perfluoroalkylated substance.