A. High Vacuum Remediation, abbreviated as HVR, is the application of vacuum to the subsurface to extract fluids and/or vapor phase substances. The fluids may include groundwater and/or Light Non-Aqueous Phase Liquids (LNAPL). Typical vacuums applied during HVR range from approximately 10 to 29 inches of Mercury (one inch of Mercury equals 13.6 inches of water column - a "perfect" vacuum is approximately 30 inches of Mercury). The normal operating range for HVR is generally from approximately 15 to 22 inches of Mercury.

A. HVR is the most aggressive LNAPL extraction technology available today for several reasons: The vacuum maximizes LNAPL and ground water flow into the extraction wells Application of the vacuum via a "stinger" or "drop tube" directly in the LNAPL zone generates horizontal flow into the extraction wells rather than the large vertical component typically associated with draw-down technologies. Typically horizontal permeabilities in sediments are much greater than vertical permeabilities. Consequently, the horizontal flow into the well due to the application of high vacuum directly in the LNAPL zone maximizes the rate at which the sediments yield LNAPL. HVR typically addresses all phases of contamination present, including LNAPL, dissolved-phase in ground water, and sorbed phase in the vadose zone. This is accomplished by maximizing the removal of LNAPL as described above by moving much of the LNAPL into the vapor phase due to the applied vacuum and then extracting it in the vapor phase (the fastest way to move contaminants through sediments) by extracting ground water with dissolved phase constituents present by "dewatering" the LNAPL zone and removing the maximum amount of LNAPL possible from this zone in both the liquid and vapor phases by accelerating vertical migration of LNAPL down from the vadose zone and into the extraction wells, and by causing the flow of fresh oxygenated air through the vadose zone thereby bioventing residual contaminants By simultaneously addressing all phases of contamination, HVR can significantly reduce or eliminate rebound, thereby dramatically shortening remediation timeframes

A. Our experience mirrors the results of a nationwide Air Force study that concluded HVR (bioslurping) typically achieved three times faster (or better) extraction rates than conventional extraction technologies

A. Bioslurping, High Vacuum Multiphase Extraction (HVME), HiVac, Dual Phase Extraction (DPE)

A. The Achilles heel of remediation has always been the tendency of its many technologies to shut down during unmanned operations - resulting in low operability rates, extended remediation timeframes, and increased costs to closure. HVR has historically suffered from this problem as well. The answer has always been to increase costs by increasing maintenance frequency so that the systems could be restarted. H2A's proprietary HVR systems have been engineered to resolve these problems technologically. Our extensive field remediation experience combined with our technological expertise in HVR has resulted in customized HVR systems that achieve very high operability rates (typically greater than 95%) with low maintenance costs.

A. Several types of vacuum generation pumps or blowers are available. However, most HVR systems utilize either a Liquid Ring Pump (LRP) or the manifold vacuum from an Internal Combustion Engine (ICE) to generate vacuum.

A. The type of equipment required for a turnkey HVR system varies from site to site depending upon the mass extraction rate of contaminants, the BTU value of those contaminants, the phase of extracted contaminants (LNAPL, ground water with dissolved phase, vapors), air permitting limitations, and discharge / disposal limitations (permit requirements). At its simplest, an HVR system may consist solely of a LRP, knockout tank, and transfer pump (with associated controls). For a more complex site, an HVR system might also include LNAPL / water separation equipment, vapor abatement equipment, dissolved-phase treatment components (e.g. air strippers, filtration), and chemical treatment (e.g. stabilization, demulsification). All of this equipment must be electronically linked to provide the seamless integration and high operabilities typical of H2A's proprietary HVR systems.

A. H2A's HVR experts have invented or applied many innovative systems to address all phases of extraction, separation, and treatment in a system that integrates all components seamlessly. One example is our proprietary LNAPL / water separation system that minimizes emulsification of LNAPL and water that can occur in other HVR systems. This improved separation process allows us to minimize further water treatment, thereby reducing the complexity and footprint of our turnkey proprietary systems. The key difference with an H2A system is that the entire turnkey system is seamlessly interlinked and designed to address all phases of contamination, separation, treatment, and discharge with high operabilities and low maintenance.