Central New York Former Gas Station

Chemical oxidation was used to degrade benzene, toluene, ethylbenzene and xylene (BTEX) compounds present in soil and groundwater at a site in Central New York during October 28-29, 2009.

Utilization of free radical chemistry, oxidation chemistry and facultative biological oxidation was implemented in such a way as to extend the oxidant and free radical residuals while enhancing the in-situ environment so that it is suitable for biologically based attenuation.

The 39 injection events were distributed to the subsurface via alphanumeric points. The programs were designed to influence an approximate area of 9,225 sq ft over an eight foot vertical zone.

The two phase program effectively introduces the remedial chemicals sodium persulfate, hydrogen peroxide and zero-valent iron (ZVI) directly into the soil and groundwater using direct push technologies, and retractable injection points through which the remedial materials were pumped into the targeted zones.

Phase one of the degradation program targeted BTEX compounds via hydroxyl and sulfate free radicals, the second utilized the decomposition products of the phase one reactions to effect facultative biological activity. A modified Fenton's chemistry and persulfate chemistry was integrated at the site, utilizing zero-valent iron as a catalyst for both reactions.

Total VOC concentrations decreased by 56% site-wide in the year following the remedial event. The biological stage of the remedial event was dominating one year after injection.