ISCO of TCE-Impacted Groundwater in Bedrock through an Enhanced

Fracture Network

Authors: Omer J. Uppal, Brian Blum, Kyle Warren,

Erica Sterzinar, and Annie Lee

PRESENTATION OUTLINE

• Site Background • COCs, geology/hydrogeology, remedial objective

previous ISCO remedial actions/timeline

• ISCO Implementation - 2011 • Enhanced Fracture Network

• Permanganate Injections

• Post-Remediation Results

• Next Steps • Technical Impracticability

SITE BACKGROUND

• 200 Acre Industrial R&D Facility Since the 1940s

• Trichloroethene (TCE) plume identified in the early 1980s

• The plume occupies an area of approximately 3 million square feet.

• ISRA triggered in 1996

Intermediate Zone TCE Plume

SOURCE ZONE “B”

SOURCE ZONE “A”

SITE GEOLOGY

• Four stratigraphic units

• Glacial Till

• Saprolite

• Columnar Basalt – Target Formation

• Feltville Formation

• Vertical faults and columnar nature of joints likely facilitated vertical migration of contaminants.

• Poorly connected fractures form a complex network with low hydraulic connectivity.

SITE CONCEPTUAL MODEL

PREVIOUS REMEDIAL ACTIVITIES

• DNAPL Source Zone Pilot Tests

• Implementation of SVE Pilot Test – 2003

• Implementation of ISCO Pilot Test – 2003

• Blast fracture trenches

installation – 2006

• 51,024 gallons (31,320 lbs.) 2.5% Potassium Permanganate & 10% Sodium Permanganate Solution injected from 2003 to 2009

NOVEMBER 2005

JANUARY 2008

INTERMEDIATE ZONE TCE PLUME

REMEDIAL ACTIVITIES

• 9 Blast fracture trenches totaling approximately 21,400 linear feet were installed on site to facilitate chemical oxidant injections

• 327 blast and injection boreholes

SEPTEMBER 2011

JANUARY 2008

INTERMEDIATE ZONE TCE PLUME

TRENCH CROSS SECTION

KMnO4/NaMnO4

TRENCH LAYOUT

ISCO INJECTION - 2011

• Additional Injections October through November 2011

• The objective was to mitigate the residual “source” of TCE groundwater plume with concentrations greater than 1,000 ppb.

INTERMEDIATE ZONE TCE PLUME

SEPTEMBER 2011

ISCO INJECTION - 2011

• 43,200 gallons (9,151 lbs.) 2.5% Potassium Permanganate solution injected into 32 intermediate injection wells and 8 deep injection wells

• Hydraulic fracturing

• Injection pressures were up to 100 PSI.

ISCO INJECTION - 2011

• Techniques used to facilitate oxidant delivery

• Specially designed oxidant distribution manifolds

• High pressure wellhead assemblies

• Overnight gravity feed injection scheme

BEDROCK INJECTION STRATEGY

• Six deep injection wells and 1 Intermediate injection well were hydro-fractured to facilitate chemical oxidant injections.

• Overnight gravity feed to facilitate improved injection rates.

• The project scope was finished several weeks ahead of schedule and under budget due to these aggressive injection strategies.

ISCO ACTIVITIES

TOTAL OF ALL ISCO ACTIVITIES

Potassium

Permanganate

(lbs)

Sodium

Permanganate

(KMnO4 equiv lbs)1

10% Modified

Fenton's Reagent

(gallons)

Pilot Test

October 2003 to December 2003 4,320 -- --

Interim Remedial Measure

June 2006 to November 2007 5,870 18,480 1,270

DNAPL Entry Zone Oxidant Placement

October 2007 1,600 200 --

Supplemental Injections

October to November 2009 850 -- --

Additional Injections

October to November 2011 9,150 -- --

Totals 21,790 18,680 1,270

GRAND TOTAL 40,470 pounds

REMEDIAL ACTION RESULTS

INTERMEDIATE ZONE

REMEDIAL ACTION RESULTS

DEEP 1 ZONE

REMEDIAL ACTION RESULTS

• Reduction in size of groundwater plume • 71% reduction in intermediate bedrock zone

• 21% reduction in deep 1 bedrock zone

• Reduction in average TCE concentrations by 88%

• Limited additional ISCO injection planned for the intermediate zone in 2014

• Remaining TCE concentrations are expected to decrease over time

REMEDIAL ACTION RESULTS

TECHNICAL IMPRACTABILITY WAIVER

• Groundwater contamination depth extends up to 585 feet bgs.

• Fracture diameter, spacing, orientation, vertical extent, and connectivity within and between formations cannot be accurately determined.

• Dissolved TCE contamination has diffused into interstitial spaces, dead-end fractures and solution voids along contaminated fracture flow paths.

• Approximately 1.6 million square feet of the plume underlies a developed residential area.

• Limitations of subsurface remediation technologies

QUESTIONS?