In Situ Chemical Oxidation for Groundwater Remediation: New

Developments and Directions

Michelle Crimi Associate Professor Clarkson University Institute for a Sustainable Environment July 4th, 2014

Introduction

Drinking water usage in the Netherlands

• Over the past 20-30 years, ~500,000 sites with potential contamination have been reported in the U.S.

• Over 100 million people (37%) in the U.S. depend on groundwater

Challenging Site Conditions

• Significant NAPL mass • Large, diffuse plumes • Highly heterogeneous sites

Emerging Technologies/Approaches

• Improved monitoring and assessment

• Coupling ISCO with other remedies

• Enhanced delivery methods

Improved Monitoring / Assessment

• Field methods

– Integrated use of real-time monitoring methods for process control

• Automated, real-time sensor networks

– Oxidation-reduction potential (ORP) and electrical conductivity (EC) probes connected to data loggers

• Real-time data for oxidant distribution

Coupling ISCO

• ISCO Enhanced bioremediation

• ISCO Monitoring natural attenuation

• ISCO using multiple oxidants

• ISCO and ISCR

• ISCO with surfactants

• ISCO with thermal

• Compatibility

• Interim goals with contingency plans

• Anticipating and confirming changes to site conceptual model

• Expertise in multiple technologies

Enhanced Delivery Methods

• Oxidant delivery can be improved

– Improved hydraulic delivery and distribution of the solution containing the oxidant

• Density-driven delivery

• Mechanical mixing

– Improved oxidant stability and/or targeted reactivity toward the contaminants

• Increased contact duration

• Increased extent of distribution

Examples

• Polymers and delivery aids

– Improve movement into low permeability zones and contact between oxidant and contaminant

• Encapsulated oxidants

– Slow and long-term release of oxidant due to diffusion or due to interaction of contaminant with encapsulating material

• Wax cylinders containing oxidant

Polymers for enhanced oxidant delivery

Case Study

● Marine Corps Base Camp Lejeune, North Carolina

● OU 15, Site 88

● Former base drycleaner facility

PCE contamination

PCE: 8400 TCE: 180 c-DCE: <250 VC: <250

mg/L

Depths of CMT 1 ports: 1-2 = 33’ 1-3 = 44’ 1-4 = 53’ 1-5 = 58’

Depths of CMT 2 ports: 2-2 = 30.5’ 2-3 = 36’ 2-4 = 43.5’ 2-5 = 58’

Depths of CMT 3 ports: 3-2 = 40’ 3-3 = 47’ 3-4 = 53’ 3-5 = 57.5’

Depths of CMT 4 ports: 4-1 = 40’ 4-2 = 49’ 4-3 = 54’ 4-4 = 58’

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CP-DPT5 CP-DPT11 CP-DPT6 CP-DPT3IW-4 CP-DPT2

0 7 1171115

De

pth

(ft,

bgs

)

Distance (ft, from injection well)

Clays Clayey Sand Silty Sands Fine Sands Med. Sands Cemented Sands No Recovery

Observed MnO4 Probable MnO4 Loose & Saturated Materials

CP-A CP-A’

Control Plot

Test Plot

Clays Clayey Sand Silty Sands Fine Sands Med. Sands Cemented Sands No Recovery

Observed MnO4 Probable MnO4 Loose & Saturated Materials

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TP-DPT5 TP-DPT4 TP-DPT3 TP-DPT1IW-3 TP-DPT9

0 7 1171115

De

pth

(ft,

bgs

)

Distance (ft, from injection well)

TP-DPT11

4

TP-A TP-A’

N

N

N

N

Control Plot: Sweep = 33% Test Plot: Sweep = 66%

Slow release oxidants

Case Study

• Solid product formed as cylinder – oxidant in wax

• Configurations

– Permeable reactive barrier

– Funnel and gate

– Grid

• Emplacement

– Direct push

– Wells

• Oxidants

– Permanganate

– Persulfate

Technology/Methodology Description

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Permanganate Cylinder – placed at bottom Persulfate Cylinders –

placed at bottom

Permanganate front

1-D Column Studies

NAS North Island OU 11

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Source Area

Down Gradient Plume

Engineering Design Tool Development

• Engineering guidance in form of practical spreadsheet tool

– Open source

– Oxidant release and reactive transport

– Contaminant degradation

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Design Tool Development

Field Demonstration/

Validation

Treatability Studies

Preliminary Laboratory Tests