Global Remediation Technologies, Inc. (GRT) performed a sodium permanganate pilot test to determine if post-surfactant treated TCE and VOC byproducts could be effectively treated in groundwater without concern for metals mobilization.

In situ Permanganate Pilot Study
Initial contaminant concentrations (average):

• 275,820 μg/L TCE
• 8,980 μg/L DCE
• 1,320 μg/L VC
• 163,820 μg/L MIBK
• 190,540 μg/L acetone

Experimental Approach
GRT performed bench scale test to determine if site conditions were suitable for permanganate treatment. Following a successful bench test, GRT performed paired well pilot test in the TCE source area using 3 injection wells and 3 extraction wells. Measurements were made of pre and post treatment concentrations of TCE, DCE, VC, MIBK, and acetone. The potential for mobilization of natural metals (chromium, manganese, mercury, and selenium) and their subsequent fate was examined. GRT determined whether soil or well screen plugging would be a problem at or near permanganate injection wells. Practical information and design parameters (e.g., dosage) for full-scale application were provided.

Summary

• GRT observed total halocarbon destruction efficiencies of 47.8%, 96.4%, and 99.9% occurred respectively in 3-paired well sets (DNAPL was later found where low destruction was observed).
• The dosage rate of 8.4 g MnO4/kg soil was adequate.
• Limited metals mobilization– concentrations returned to background 18-foot downgradient of treatment zone.
• Evidence existed of very limited soil plugging by MnO2 solids.
• Contaminant rebound was observed following treatment.

Bench Study
Bench study results demonstrated VOC and SVOC reductions in groundwater and soil slurries greater than 99%. Based on the bench study results, the Project Team deemed the site a viable candidate for modified Fenton’s reagent based chemical oxidation and moved forward with the Pilot Study.

Field Study
First Injection:

• 75% reduction in Chemicals of Concern (COC) mass in the soil
• 21% reduction in COC mass in the groundwater (inside treatment area)
• 4% reduction in COC mass in the groundwater (outside the treatment area)
• Metals mobilized but decreasing with time and appeared limited to injection area

Second Injection:

• Net increase in COC mass relative to the first injection (75% reduction fell to 70% reduction) in the soil
• 3% increase in COC mass in the groundwater (inside treatment area)
• 191% increase in COC mass in the groundwater (outside the treatment area)
• Metals mobilizing to outer wells (Copper, nickel, vanadium, zinc above regulatory criteria)

Summary

• Based on soil COC concentrations, a substantial portion of the sorbed phase mass had been destroyed.
• Dissolved phase concentrations are on average lower than before the pilot study.
• The pilot study results (metals mobilizing) prevented the project team from going to full-scale treatment.

Note: Bench scale and pilot scale testing performed by In Situ Oxidative Technologies (ISOTEC) with GRT over-sight. Collaborative project involving the former refinery, the refinery’s lead consulting firm, GRT, and ISOTEC.