Abstract: The present invention provides methods and systems for the in situ remediation of contaminated sites. In some embodiments, the methods and systems include one or more conduits for injection or coinjection of liquid electron donor compositions and dispersant gas compositions.

Abstract: The specification discloses a system for recovering groundwater from a subterranean aquifer through an extraction well having a perforated casing extending down to the water table and a drop-tube within the casing to define an annular area between the casing and the drop-tube. A vacuum pump is connected to the drop-tube for inducing a flow of liquid up the tube. An aperture is provided through the wall of the drop-tube to enable gas from the annular area to enter the drop tube to mix with liquids flowing upwardly through the tube and reduce the density of the flowing fluid column so that it is more easily lifted to the surface. The aperture also provides a self-priming feature which avoids start-up problems associated with known vacuum dewatering methods.

Abstract: The specification discloses a system for recovering groundwater from a subterranean aquifer through an extraction well having a perforated casing extending down to the water table and a drop-tube within the casing to define an annular area between the casing and the drop-tube. A vacuum pump is connected to the drop-tube for inducing a flow of liquid up the tube. An aperture is provided through the wall of the drop-tube to enable gas from the annular area to enter the drop tube to mix with liquids flowing upwardly through the tube and reduce the density of the flowing fluid column so that it is more easily lifted to the surface. The aperture also provides a self-priming feature which avoids start-up problems associated with known vacuum dewatering methods.