Former Gas Station UST Release—Southwest Illinois

ORIN successfully treated BTEX, MTBE, & Naphthalene contaminated plume with ex-situ chemical oxidation. An excavator was present to displace a certain area of soil down to depth. A portion of that soil was then placed back into the excavated hole while the treatment chemistry was being applied to the soil.

The excavator would then continually mix the soil and chemicals together until the desired amount of treatment chemistry was applied. More soil was then added from the displaced pile while additional chemical was applied and mixed thoroughly. This process was duplicated until the desired consistency and chemical volume were applied to the entire targeted soil volume.

The Challenge

The site presented multiple contaminants:

• BTEX compounds
• MTBE
• Naphthalene
• Contaminated soil plume
• IEPA compliance requirements
• Multiple treatment objectives

The Solution: Systematic Ex-Situ Treatment

The team implemented a precise batch treatment process:

1. Excavation Phase:
   • Strategic soil removal
   • Depth-specific targeting
   • Controlled soil management
   • Treatment zone preparation
2. Treatment Process:
   • Fenton’s Reagent application
   • Systematic soil replacement
   • Continuous mixing protocol
   • Sequential batch treatment
   • Quality control monitoring

Implementation Strategy

Key operational elements included:

• Controlled soil return
• Progressive chemical application
• Continuous mechanical mixing
• Batch process optimization
• Consistency verification

Impressive Results

The treatment achieved multiple objectives:

• Over 97% contaminant reduction
• Met IEPA Tier 1 Commercial Standards
• Successful multi-contaminant treatment
• Verified within two weeks
• Complete regulatory compliance

Key Success Factors

Several elements contributed to success:

1. Strategic batch processing
2. Thorough mixing protocol
3. Precise chemical application
4. Quality control measures
5. Rapid verification testing

Innovation Highlights

The project demonstrated several advantages:

• Effective batch treatment
• Rapid results verification
• Multiple contaminant removal
• Regulatory compliance achievement
• Efficient process management

Regulatory Achievement

The success included:

• Met IEPA Tier 1 Standards
• Complete documentation
• Rapid compliance verification
• Clear success metrics
• Validated methodology

This case study demonstrates how systematic ex-situ treatment can achieve both high contaminant reduction and strict regulatory compliance.