Case Studies of Fenton's Reagent ISCO at MGP and Chlorinated Solvent Sites

Fenton’s reagent often provides excellent cost and technical efficiency to address concentrated source areas, particularly those impacted with chlorinated solvents and DNAPLs. Application to manufactured gas plants (MGPs), generally impacted by high concentrations of polynuclear aromatic hydrocarbons (PAHs) and coal tar DNAPL in soil and groundwater, is also a promising new use of Fenton’s reagent ISCO. Two case studies are presented of source area remediation using Fenton’s reagent: Naval Submarine Base (NSB) Kings Bay (Georgia) and Burlington MGP (Wisconsin).

The Burlington MGP site was impacted with BTEX and PAHs exceeding 28,000 mg/kg in soil and coal tar DNAPL. The vadose zone was excavated and backfilled, and ISCO was utilized for the aquifer. Treatment consisted of bench and field pilot tests, followed by full-scale treatment conducted over the past three construction seasons. A shallow silt area was covered with a geomembrane to promote reagent distribution within the silt. Results through the 2001 construction season (second year) indicate approximately 80% contaminant mass removal at the site, and remediation will be completed in November 2002.

Groundwater at NSB Kings Bay was impacted with PCE and it’s degradation products. Maximum PCE concentration exceeded 8,000 ug/L. Groundwater modeling indicated that reduction of the source area concentration to less than 100 ug/L would result in degradation of the solvents before migrating offpost. Treatment was conducted in four phases. The suspected source area was addressed in Phase I. Phase II focused on a downgradient portion of the site and a small upgradient area that rebounded following Phase I. After Phase II, the upgradient area again rebounded. The Navy excavated the area and removed three crushed drums containing residual PCE. Subsequently, Phase III re-addressed this area. Phase IV addressed deeper contamination and completed the remediation with vegetable oil injection to stimulate natural degradation of remaining dissolved contaminants.