ARCHIVED REPORTS XR0001782 - Laserfiche WebLink

Home Browse Search

LFR Levine-Fricke Rev rsed These data will be used to estimate flow rates and to calculate the mirumum number of Pore volumes to be extracted, which will result m effective remediation of VOC- affected soil This estimation may be through a series of pore gas velocity calculations, iterative gas flow modeling as presented by DiQulio and Varadharn (2001), or through the use of the public domain model AIRM, Such dual consideration of ROI combined with pore gas velocity considerations will result in a more cost and tune efficient soli vapor extraction system- 6.2.1 Soil Air Permeability Calculations Soil air permeability will be estunated using the data collected with the constant rate discharge tests in the extraction wells tested during the pilot study- Two types of air permeability calculations will be performed: • De Glee's distance versus drawdown method (for multiple monitoring wells) Hantush Jacob's tune versus drawdown method (for a single monitoring well) Both of these methods were originally developed for estimating hydraulic parameters of aquifers, but are also applicable for analyzing SVE data (Thrupp et al 1996). Analytic limitations regarding differences in the physical propenes of fluids and vapors do exist, but historically, have not had a significant effect on air permeability calculations • (Massmann 1989) 6.2.2 Radius of Influence and Critical Porus Velocity Evaluation Radius of Influence During, each of the step and constant discharge tests, vacuum responses in monitoring wells due to active extraction from a pilot test will be monitored. During each test sequence, steady state vacuum measurements will be identified in each of the monitoring wells Vacuum response is expected to decrease logarithnvcally in a radial pattern relative to the distance from the vacuum source (i.e , the test extraction well) Eased on data collected, a TMROI for a given constant flow rate will be estimated For the purposes of this study, the TMROI will be defined as the farthest average radial distance from an operating SVE well at which vacuum response of 0,1 u2 of H2,0 could be measured in the subsurface Critical Pore-Gas Velocity For assessing the critical pore-gas velocity, LFR will use the of the ROI data, soil air Permeability calculations, and a series of pore gas velocity calculations, iterative gas flow modeling as presented by DiGiulio and Varadharii (2001), or public domain model AMD Such consideration of ROI combined with pore gas velocity considerations will . result in a more cost and time efficient soil vapor extraction system through e 2.0 wpSVLii$-Lada-mv48123 dot 1fr 02!ig0 d B£T0b9b602T 01 906V zS9 OTS 9N0Id9 9NIMD-1 d9I Nj 6b 91 Z0. 60 7nr