Air Sparging is an In-Situ remedial technology that reduces concentrations of volatile constituents in petroleum products that are adsorbed to soils and dissolved in groundwater. This technology, which is also known as “In-Situ air stripping” and “In-Situ volatilization,” involves the injection of contaminant-free air into the subsurface saturated zone, enabling a phase transfer of hydrocarbons from a dissolved state to a vapor phase. The air is then vented through the unsaturated zone into the open Atmosphere. Compared to “Bio Sparging” Air Sparging will require more airflow to obtain the in situ air stripping affect.

Air Sparging is most often used together with soil vapor extraction (SVE), but it can also be used with other remedial technologies or even alone. When Air Sparging (AS) is combined with Soil Vapor Extraction (SVE), the SVE system creates a negative pressure in the unsaturated zone through a series of extraction wells to capture vapors and control the vapor plume migration. This combined system is called AS/SVE. An Air Sparging pilot test is recommended for adequate design.

Application
When used appropriately, Air Sparging has been found to be effective in reducing concentrations of volatile organic compounds (VOCs) found in petroleum products at underground storage tank (UST) sites. Air Sparging is generally more applicable to the lighter gasoline constituents (i.e., benzene, ethyl benzene, toluene, and xylene [BTEX]), because they readily transfer from the dissolved to the gaseous phase. Air Sparging is less applicable to diesel fuel and kerosene. Appropriate use of Air Sparging may require that it be combined with other remedial methods (e.g., SVE or pump-and-treat). An Air Sparging system can use either vertical or horizontal sparge wells. Well orientation should be based on site-specific needs and conditions. Unfortunately many governmental organizations are now disallowing this method due to the fact that it vents the contaminants into the Atm0sphere