Comparison of one- and three-dimensional soil vapour extraction experiments

Area of Science:

• Environmental Engineering
• Geotechnical Engineering
• Chemical Engineering

Background:

• Soil vapor extraction (SVE) is a widely used technology for remediating gasoline-contaminated soil.
• Most SVE research has focused on one-dimensional models, which may not accurately represent real-world three-dimensional extraction processes.

Purpose of the Study:

• To investigate the impact of experimental configuration (one-dimensional vs. radial column) on SVE performance.
• To determine if laboratory-scale experiments can reveal mass transfer limitations relevant to field-scale SVE operations.

Main Methods:

• Conducted one-dimensional and radial column laboratory experiments using two soil types and toluene as the contaminant.
• Varied air flow rates and analyzed results both qualitatively and quantitatively.
• Calculated mass transfer coefficients for quantitative comparison.

Main Results:

• Both experimental setups achieved good mass closures.
• One-dimensional experiments showed no significant mass transfer limitations within the tested air flow rates.
• Radial column experiments revealed mass transfer limitations not observed in the one-dimensional setup.

Conclusions:

• Laboratory experimental geometry influences the observed mass transfer characteristics in soil vapor extraction.
• Radial column experiments provide insights into potential mass transfer limitations missed by one-dimensional models.
• Further investigation using radial columns is crucial for improving the predictive accuracy of field-scale SVE performance.