What kind of contaminants does soil vapor extraction work on?

It works best on volatile and semi-volatile organic compounds, such as gasoline components and many solvents, which readily evaporate into soil air where airflow can carry them to extraction wells; non-volatile contaminants are not removed this way.

Why does soil type matter for vapor extraction?

The method relies on drawing air through the soil, so permeable, well-drained soils allow effective airflow and contaminant removal, while dense clays restrict airflow and make the technique much less efficient.

Soil Vapor Extraction

Soil vapor extraction is an in-situ method that removes volatile contaminants from unsaturated soil by inducing airflow.

Definition

An in-situ remediation method that applies a vacuum to wells in unsaturated soil to induce airflow, volatilizing and removing volatile organic contaminants for above-ground treatment.

Scope

This topic covers soil vapor extraction, an in-situ remediation technique for volatile and semi-volatile contaminants in the unsaturated zone. It addresses how applying a vacuum to extraction wells draws air through the soil, volatilizing contaminants and carrying them to the surface for treatment, the contaminant and soil properties that make a site suitable, and related approaches such as air sparging that extend the method to saturated zones.

Core questions

How does soil vapor extraction remove contaminants from soil?
Which contaminants and soil conditions favor the method?
How is the extracted vapor treated at the surface?
How does air sparging extend the approach below the water table?

Key theories

Volatilization-driven mass removal: Inducing airflow through the unsaturated zone shifts volatile contaminants from soil and pore water into the vapor phase, where they are swept to extraction wells and removed, making volatility a key determinant of effectiveness.
Permeability and airflow: The success of vapor extraction depends on soil permeability to air, since well-drained, permeable soils allow the airflow needed to volatilize and capture contaminants, whereas tight soils limit it.

Clinical relevance

Soil vapor extraction offers a relatively low-disturbance, in-situ route to remove volatile contaminants such as fuel and solvent vapors from soil, reducing sources that would otherwise contaminate groundwater and air.

Evidence & guidelines

Application of vapor extraction draws on design principles relating airflow, volatility, and permeability; these are described here to explain the method rather than as prescriptive guidance.

History

Soil vapor extraction became a widely used in-situ remedy in the 1980s and 1990s, particularly for petroleum and solvent contamination, as an alternative to excavation for volatile contaminants in the vadose zone.

Seminal works

suthersan1996
fetter2018
manahan2017

Frequently asked questions

What kind of contaminants does soil vapor extraction work on?: It works best on volatile and semi-volatile organic compounds, such as gasoline components and many solvents, which readily evaporate into soil air where airflow can carry them to extraction wells; non-volatile contaminants are not removed this way.
Why does soil type matter for vapor extraction?: The method relies on drawing air through the soil, so permeable, well-drained soils allow effective airflow and contaminant removal, while dense clays restrict airflow and make the technique much less efficient.