Can Modified Fenton’s Reagent be Used at Sites with Light Non-aqueous Phase Liquid (LNAPL)?

Over the years, we occasionally receive calls where a client asks whether or not modified Fenton's reagent (i.e. hydrogen peroxide and an iron catalyst) can be used at a site where LNAPL is present.  Historically, the application of Fenton's reagent at sites with significant thicknesses of LNAPL has not often been recommended due to potential safety concerns or potential mobilization of NAPL.  Additionally, the application of any oxidant as a sole remedial option at a site containing substantial volumes of NAPL needs to be carefully considered, because the presence of NAPL should be seen as an indication that the mass of oxidant required could be cost prohibitive.  That said, the presence of measurable NAPL should not necessarily preclude the use of Fenton's Reagent as a significant remedial option, in some cases.

Norfolk has had substantial success in using Fenton's Reagent in conjunction with oil recovery mechanisms to enhance the recovery of heating oils and similar petroleum products.  The application of fluid temporarily reduces pore pressures and can "liberate" oil from the soil matrix.  Heat and gasses generated by the Fenton's Reagent can a do the same and also temporarily reduce the viscosity of the oil, thereby creating an opportunity to enhance recovery efforts.  We often find that LNAPL thickness will increase in wells after Fenton's Reagent applications and that oil recovery wells that had previously reached a point of diminishing returns, in terms of oil recovery, will become more productive.  At the same time, treatment of surrounding areas of the site is also accomplished (e.g. an overlying unsaturated soil zone, smear zone, and/or soils and groundwater surrounding the area of NAPL).