PRODUCTION AND ACCUMULATION OF SURFACTANTS DURING THE CHEMICAL OXIDATION OF PAH IN SOIL

Slurry reactors containing polycyclic aromatic hydrocarbons (PAH) contaminated soils were treated using three types of chemical oxidants: (1) a calcium peroxide powder known as Cool-Ox^TM, (2) hydrogen peroxide, and (3) sodium persulfate activated with Fe chelated using ethylenediaminetetraacetic acid (EDTA). These substances were used to induce chemical oxidation via modified Fenton chemistry. Samples of slurry filtrate were tested to quantify emulsification of PAH and concentrations of bulk surfactants, using the critical micelle dilution method. All three oxidants produced surfactants reaching levels above the critical micelle concentration (CMC), though the surfactants were removed at the end of treatment. Emulsification of PAH was achieved, and the removal of 5- and 6-ring PAH was greater than biodegradation alone. Treatment with Cool-Ox^TM resulted in the highest concentration of surfactants (4 times the CMC), the most emulsification of PAH, and the highest removal of 5- and 6-ring PAH.