DUAL PHASE EXTRACTION

Dual-phase extraction (DPE), also known as multi-phase extraction, is a technology that uses a high vacuum system to remove both contaminated groundwater and soil vapors. A single vacuum source (vacuum pump or blower) is used to extract both liquid and gaseous phases in the same conduit or pipe. In DPE systems a high vacuum extraction well is installed (by others) with its screened section in the zone of contaminated soils and groundwater. During the Fluid/vapor extraction process, the water table is depressed and the fluids flow faster towards the extraction well. This process removes contaminants from above and below the water table. As the water table around the well is lowered exposing the unsaturated soil. This area, called the capillary fringe, is often highly contaminated. Contaminants in the newly exposed zone can now easily be removed by the vapor extraction process. Once above ground, these extracted vapors groundwater are then separated and treated. Use of dual-phase extraction can shorten the cleanup time at a site, as the capillary fringe is often the most contaminated area.