Soil Vapor Extraction

SVE works best on volatile organic compounds (VOCs) and some semi-volatile organic compounds (SVOCs) with sufficiently high vapor pressure to transition from adsorbed or dissolved phases into the soil gas phase, such as gasoline constituents, chlorinated solvents like TCE and PCE, and other light petroleum hydrocarbons. Wintek supports these applications with vacuum systems designed for a wide operating range (10”–28” HgV) and technologies like integrated humidity control to optimize downstream carbon adsorption, helping improve removal efficiency and reduce operating costs.

Contaminants with low vapor pressure, such as heavier oils, greases, or PAHs, don’t readily volatilize into soil vapor under the vacuum levels typically applied, making SVE inefficient or ineffective for these compound types compared to more volatile contaminants.

Soil permeability strongly influences how effectively vacuum can be transmitted through the subsurface and how well contaminated vapor can flow toward extraction wells, so coarse, permeable soils like sand typically respond well to SVE, while low permeability soils like clay or silt can significantly limit airflow and reduce system effectiveness.

A standard SVE system includes extraction wells screened in the contaminated interval, a network of piping connecting the wells to a vacuum source, a vacuum pump or blower to generate the extraction vacuum, a moisture separator or knockout tank to remove entrained water, and a vapor treatment system to handle the extracted contaminants before discharge. Wintek supplies these systems with proven components such as oil-sealed liquid ring vacuum pumps and integrated knockout pots, delivering reliable performance and long-term uptime in demanding field conditions.

Regenerative blowers and liquid ring vacuum pumps are used depending on the required vacuum level and flow rate, with liquid ring pumps often selected for sites where deeper vacuum is needed or where moisture and vapor conditions favor a technology tolerant of liquid carryover. Wintek provides both solutions, including oil-sealed liquid ring vacuum systems for higher vacuum applications (15–28” HgV) that offer improved reliability and resistance to the scaling issues common with water-sealed designs, helping maintain consistent performance in challenging SVE conditions.

Extracted soil vapor contains the contaminants being removed from the subsurface, so regulatory discharge limits typically require treatment before release, commonly using technologies like granular activated carbon adsorption, thermal or catalytic oxidation, or condensation, depending on contaminant type and concentration.

A pilot test is a short term trial extraction run at the site that measures achievable vacuum, airflow rates, and radius of influence under actual field conditions, providing the data needed to properly size and design the full scale system rather than relying on generic assumptions.

Yes, SVE is frequently paired with technologies such as air sparging, which injects air below the water table to volatilize contaminants that then migrate upward into the vadose zone for SVE capture, or with bioventing, which uses the induced airflow to also stimulate aerobic biodegradation of contaminants. Wintek supports these integrated approaches with vacuum systems designed to handle variable vapor and moisture loads, including oil-sealed liquid ring pumps that maintain reliable performance even with liquid carryover.

SVE operates above the water table in the unsaturated zone, using vacuum to extract vapor, while air sparging operates below the water table, injecting air to volatilize and strip contaminants from groundwater, with the two technologies often used together to address both saturated and unsaturated zone contamination.