Passive Soil Vapor Extraction - GSI Environmental Inc.

SRNL-STI-2009-00571Rev. 1Figure 5.3: Comparison of Soil Gas Flow generated during a Barometric Application versus thatgenerated using a MicroBlower at SRS, SC.While barometric applications can generate higher instantaneous flows during outflowconditions, the intermittent nature of the application may make selection of barometricpumping unfeasible.i. Is the Average Pressure Differential between Atmospheric and Target SubsurfaceZone Sufficient to Meet Target Mass Flux Goals?This decision point requires a yes/noresponse based on the target mass fluxgoals determined earlier and the averagemass flux that can be achieved usingbarometric pumping. In addition to thedata requirements outlined in the previoussection, the pilot study for evaluation ofbarometric pumping should be designedto collect long-term surface andsubsurface pressure data as wellas barometric soil gas flow rates.Methods for collection of this data are described in Section 2.4. See Appendix Afor predicted values for soil gas flow rate and contaminant mass flux based onthe physical properties of the overlying soil and the affected soil layers.42 Enhanced Attenuation TechnologiesPassive Soil Vapor Extraction