The ART® Technology combines in situ air stripping, air-sparging, soil vapor extraction (SVE), and enhanced bioremediation/oxidation - plus subsurface groundwater circulation. The ART® Technology is designed for installation within a four-inch or larger well. The combined remediation concepts and subsurface effects of a typical ART® well are depicted in the Cross Section.

The air-sparging component results in reduced water density and lifting (mounding) of the water table in the vicinity of the well. This in turn causes a net negative gradient to the well, resulting in water flowing back toward the well. This upwelling force created by the sparging results in an in-well "packer" concept, resulting in pressure and density gradient from the lower screened interval to the upper screened interval that assists in driving the dynamic subsurface circulation forces.

Vacuum pressure (the vapor extraction) component is applied at the top of the well point to extract vapor from the subsurface. The negative pressure from vacuum extraction creates additional water mounding and boosts the net gradient back toward the well; it also removes vapors from the unsaturated zone and well annulus. The SVE and sparging combined in the same well further enlarges the radius of influence and boosts circulation.

A submersible pump is placed at the bottom of the well to recirculate water to the top for downward discharge through a spray head. The water cascades down the interior of the well and system piping, providing multiple wetted surfaces for mass transfer, similar to what occurs in a packed-column air-stripping tower. Enhanced stripping via air sparging near the bottom of the well occurs simultaneously. In essence, the well acts as a subsurface air-stripping tower, in which the pumped and stripped, dissolved-oxygen-rich water flows down the well annulus and over the mounded water back into the aquifer and vadose zone. This action hydraulically enhances the radius of influence and flushes contamination from this zone. Ultraviolet treatment units and/or the addition of ozone to the air-sparging stream are options that can be incorporated with the ART® Technology at minimal expense and effort. When these are combined, the synergistic technology effects create a circulation zone surrounding the well that further enhances cleanup.

In summary, contaminants are stripped from the water as a result of the combined effects of in-well air stripping and in-well air sparging. The "radius of results," or dynamic subsurface circulation cleaning zone, is created by a combination of negative gradient from air sparging, the application of vacuum extraction, and subsurface water circulation induced by a submersible pump. A radius of influence of up to ten times the water column in the ART® remediation wells has been achieved at sites where the technology was implemented. All of these different components are integrated in the ART® Technology and can be installed in a four-inch (minimum) groundwater well. Another primary benefit of the technology that separates it from similar remedial alternatives is its potential to treat the same unit of water as many times as necessary because of the multiple stripping passes that can be achieved.