Pressure extraction process for removing soil and groundwater contaminants

摘要

A pressure extraction process for removal of underground contaminants from subsurface soil and groundwater comprises establishing a well through the unsaturated soil into the underlying groundwater unit, with the well including an exterior pipe having fluid permeable openings therein at a lower portion that extends above and below the groundwater surface. An interior pipe is provided inside the exterior pipe and has an inlet opening below the groundwater surface. Oxygen-containing gas is injected into the exterior pipe at a non-vacuum pressure. Preferably the pressure is sufficient to cause some of the gas to flow outwardly into the soil through the pipe openings. A gas pressure flow is established downwardly in the exterior pipe to the inlet of the interior pipe and then upwardly through the interior pipe and out of the well. The gas pressure in the exterior pipe is maintained at a sufficiently low level in comparison with the hydraulic pressure outside the well adjacent the inlet to the interior pipe that liquid is induced to flow into the exterior pipe and to the inlet of the interior pipe, whereby the liquid is conveyed up the interior pipe by the flowing gas. The gaseous-phase and liquid-phase components removed from the well are separated and treated to remove contaminants. The treated gas can then be reintroduced as pressurized gas in the exterior pipe of the well or discharged to atmosphere, and decontaminated water can be used or released to the groundwater or surface water.