The Baroball™ is a patented valve making it possible to harnesses natural atmospheric pressure fluctuations to create a pumping method that passively removes vapors from the unsaturated soil zone (Passive Soil Vapor Extraction). (View an illustration of the barometric pumping process with Baroball.) This technology has been demonstrated to increase removal rates by up to 50%. Natural atmospheric pressure fluctuations are transmitted through the unsaturated subsurface resulting in pressure differential between the surface and subsurface. When the zones are directly connected by a well placed in the vadose zone, the pressure differentials will result in flow into or out of the well.

Simply put, the Baroball is a check valve that is installed at the top of the well casing to permit gas flow in one direction. The Baroball has been used in conjunction with the FAP Plus™ systems to increase removal rates during LNAPL recovery. Other applications include the final polishing for an active SVE system where removal rates have been substantially reduced to the point where SVE system operation costs are very high. Inverted Baroball installations have been used to allow air flow into the subsurface, but prevent air escape to improve in-situ bioremediation.

The Baroball has also been used to provide plume control of methane production at landfills.

TR-965	Standard Baroball™ for soil gas extraction
TR-966	Inverted Baroball™ for atmospheric air injection

For more information
> Brochure (PDF 200 KB)
> Brian D. Riha (June 2005), "Passive Soil Vapor Extraction (PSVE) for VOC Remediation at the Metallurgical Laboratory (MetLab) June 2005 Progress Report", report nr WSRC-TR-2005-00268 (PDF 613 KB)