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DEMONSTRATION BULLETIN: UNTERDUCK-VERDAMPFER- BRUNNEN TECHNOLOGY (UVB) VACUUM VAPORIZING WELL - ROY F. WESTON, INC./IEG TECHNOLOGIES CORPORATION
Citation:
Simon*, M A. DEMONSTRATION BULLETIN: UNTERDUCK-VERDAMPFER- BRUNNEN TECHNOLOGY (UVB) VACUUM VAPORIZING WELL - ROY F. WESTON, INC./IEG TECHNOLOGIES CORPORATION. EPA/540/MR-95/500, 1995.
Impact/Purpose:
information
Description:
The Weston/IEG UVB technology is an in situ groundwater remediation technology that combines air-lift pumping and air stripping to clean aquifers contaminated with volatile organic compounds. A UVB system consists of a single well with two hydraulically separated screened intervals installed within a single permeable zone. The air-lift pumping occurs in response to negative pressure introduced at the wellhead by a blower. This blower creates a vacuum that draws water into the well through the lower screened portion of the well. Simultaneously, air stripping occurs as ambient air (also flowing in response to the vacuum) is introduced through a d'rffuser plate located within the upper screened section of the well, causing air bubbles to form in the water pulled into the well. The rising air bubbles provide the air-lift pump effect that moves water towards the top of the well and draws water into the lower screened section of the well. This pumping effect is supplemented by a submersible pump that ensures that water flows from bottom to top in the well at a rate of approximately 20 gal/min. As the air bubbles rise through the water column, volatile compounds are transferred from the aqueous to the gas phase. The rising air transports volatile compounds to the top of the well casing where they are removed by the vacuum blower. The blower effluent is treated before discharge using granular activated carbon. The transfer of volatile compounds is further enhanced by a stripping reactor located immediately above the air d'rffuser. The stripping reactor consists of a fluted and channelized column that facilitates the transfer of volatile compounds to the gas phase by increasing the contact time between the two phases and by minimizing the coalescence of air bubbles. Once the upward stream of water leaves the stripping reactor, the water falls back through the well casing and returns to the aquifer through the upper well screen. This return flow to the aquifer, coupled with inflow at the well bottom, circulates ground-water around the UVB well.