Multi-Phase Extraction (MPE) also known as Dual Vapor Extraction (DVE), Dual-Phase Extraction (DPE), vacuum-enhanced extraction, or sometimes Bioslurping, is an In-Situ technology that uses pumps or entrainment (slurping) to remove various combinations of contaminated groundwater, separate-phase petroleum product, and hydrocarbon vapor from the subsurface. Extracted liquids and vapor are treated and collected for disposal, or re-injected to the subsurface (where permissible under applicable state laws). Multi-Phase Extraction also allows for dewatering the saturated zone, exposing the previously saturated zone to air flow from Soil Vapor Extraction (SVE).
MPE systems can be effective in removing separate-phase product (free product) from the subsurface, thereby reducing concentrations of petroleum hydrocarbons in both the saturated and unsaturated zones of the subsurface. MPE systems are typically designed to maximize extraction rates; however, the technology also stimulates biodegradation in the unsaturated zone by increasing the supply of oxygen, in a manner similar to that of Bioventing.