In designing a Ferox^sm system, the effects of other electron receptors (i.e. nitrate, sulfates), which compete with the target organic compound, need to be considered. A recent Feroxsm application illustrates this point. Early this summer, ARS was contracted to install a FeroxSM system at a southeast government
site to address TCE source contamination. The site was a former leach/burn area for fuels and propellants. Previous remedial efforts involved the removal of contaminated soils within the former waste pits followed by ex-situ biological treatment of the excavated soils. Some of these biological treatment tests
involved the use of chicken manure, which has extremely high nitrate levels. Historically, TCE concentrations in this area have been as high as 14,000 ug/L and elevated nitrate levels as high as 288,000 mg/l. Under anaerobic conditions, oxidants such as nitrate can act as an electron receptor and potentially interfere
with the TCE-ZVI reduction reaction mechanism. Unfortunately, the reduction rate of nitrate to nitrite has been found to be faster than TCE reduction, therefore preferential reduction of the nitrate is expected. Based upon ground water sampling results, obtained 8 months after injections, TCE concentrations were reduced up to 95% in the source area. Additionally, the formation of elevated
daughter products was not observed. Along with the TCE reductions, Nitrate reductions up to 94% were also observed.