Model analysis of mechanisms controlling pneumatic soil vapor extraction

Area of Science:

• Environmental Engineering
• Geotechnical Engineering
• Subsurface Remediation

Background:

• Traditional soil vapor extraction (SVE) efficiency is limited by subsurface heterogeneity, often bypassing low-permeable contaminated zones.
• Heterogeneous subsurface environments pose challenges for effective contaminant removal using conventional methods.

Purpose of the Study:

• To evaluate the effectiveness of pneumatic SVE in enhancing remediation efficiency in heterogeneous soils.
• To analyze the physical processes governing pneumatic SVE performance through numerical simulation.
• To assess the sensitivity of pneumatic SVE to various operational and environmental conditions.

Main Methods:

• Laboratory experiments were conducted to demonstrate pneumatic SVE capabilities.
• Numerical code was employed to analyze experimental results and simulate subsurface processes.
• Sensitivity analysis was performed on boundary conditions, initial conditions, and parameters.

Main Results:

• Pneumatic SVE significantly improves contaminant recovery rates from low-permeable soil units compared to traditional SVE.
• Numerical simulations confirmed the superiority of pneumatic venting technology at the laboratory scale.
• The method shows particular efficacy in subsurface areas with substantial permeability contrasts.

Conclusions:

• Pneumatic SVE is a superior remediation technique for heterogeneous soils, especially those with significant permeability variations.
• The study quantifies the physical mechanisms driving pneumatic SVE's enhanced performance.
• This technology offers a promising solution for improving the remediation of challenging contaminated sites.