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New Groundwater Techniques and Technologies 17 th Annual RETS REMP Conference June 25-27, 2007 Eric L. Darois, CHP EPRI Consultant/RSCS Inc.

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Presentation on theme: "New Groundwater Techniques and Technologies 17 th Annual RETS REMP Conference June 25-27, 2007 Eric L. Darois, CHP EPRI Consultant/RSCS Inc."— Presentation transcript:

1 New Groundwater Techniques and Technologies 17 th Annual RETS REMP Conference June 25-27, 2007 Eric L. Darois, CHP EPRI Consultant/RSCS Inc.

2 2 © 2007 Electric Power Research Institute, Inc. All rights reserved. Project Scope Evaluate New and Current Technologies for Groundwater Sampling Evaluate New and Current Technologies for Contaminated Groundwater Detection Evaluate New and Current Technologies for Contaminated Groundwater Remediation

3 3 © 2007 Electric Power Research Institute, Inc. All rights reserved. Technology Conferences 7th Passive Sampling Workshop and Symposium, Reston Virginia, United States Geological Survey (USGS), April Ground Water Summit, Albuquerque New Mexico, National Ground Water Association (NGWA), April 2007

4 4 © 2007 Electric Power Research Institute, Inc. All rights reserved. Passive Sampling Technologies SPMD’s –Semi-Permeable Membrane Devices (SPMD’s) –These accumulate contaminants within an absorption media, typically a polyethylene absorption media. The Gore Module –Developed exclusively produced by and for GORE-TEX® –Similar to SPMD’s, does not collect a sample of water, uses a patented absorption material. –Consists of a tube of GORE-TEX® fiber containing absorption beads. –Has pore sizes large enough to allow volatile and semi-volatile gas phase contaminants to diffuse and to accumulate on the absorption material. –Pore size restricts liquid phase water from entering the sampler. PDBS –Passive Diffusion Bag Samplers (low-density polyethylene diffusion bag samplers) –Collects groundwater samples using a tube of Low Density Polyethylene (LDPE). –Fits into a 5 cm dia. well. –Filled with DI Water, sealed at both ends and lowered into Well. –Averages Concentration over 1 – 2 weeks – no additional equipment RCDMS –The Regenerated Cellulose Dialysis Membrane Sampler (RCDMS) –Similar to the PDBS. –Pore size between 5-20 microns. –May Be Susceptible to Degradation

5 5 © 2007 Electric Power Research Institute, Inc. All rights reserved. Passive Sampling Technologies (con’t) RPP –The Rigid Porous Polyethylene sampler (RPP) –Also Similar to PDBS and RCDMS –Porous polyethylene membrane with pore sizes ranging between 6 and 15 microns. –Limited to 100mL sample The Snap Sampler –Groundwater passive grab sampler. –Device consists of a sample bottle, trigger lines, end caps and springs –Sample Volumes of 40 and 125 mL. The Hydra Sleeve –Groundwater passive grab sampler. –Disposable thin-wall sleeve of polyethylene sealed on the bottom and fitted with a one way reed valve on the top. –Effectively Collects a Core of Water ~1000 mL

6 6 © 2007 Electric Power Research Institute, Inc. All rights reserved. Passive Sampling Comparisons Diffusion Sampler Grab Sampler Commercially Available Disposable Limited by Sample Volume Easy to Use Snap Sampler XXX RCDMS XX RPP XXXXX Hydra Sleeve XXXX

7 7 © 2007 Electric Power Research Institute, Inc. All rights reserved. Tritium Groundwater Contamination Detection Soil Vapor Extraction System (SVES) Current EPRI Research Initiative 4 Project Phases –1 Develop Predictive Model –2 Laboratory Testing of Model –3 System Test at a Decommissioning Site with Characterized H-3 Plume –4 System Test at Operating NPP Currently Beginning Phase 2

8 8 © 2007 Electric Power Research Institute, Inc. All rights reserved. SVES Basis Research Currently at the Armagosa Desert Research Site

9 9 © 2007 Electric Power Research Institute, Inc. All rights reserved. SVES Principle Extract Soil Vapor from Vadose Zone Condense Vapor, Analyze for H-3 The Vadose Zone H-3 Vapor “Plume” Likely Extends Well Beyond Contaminated Groundwater If the H-3 Vapor is Within the Extraction Zone of Influence, Detection will Occur. System May Provide Early Indication of H-3 Subsurface Leak.

10 10 © 2007 Electric Power Research Institute, Inc. All rights reserved. Project Objectives Determine Physical System Configuration Requirements Determined Required Data for System Installation Evaluate Sensitivity of SVES to “detect” Groundwater Contamination Provide for Data Assessment Methodologies Prediction of: –Soil Gas Velocity –Radius of Influence –Subsurface Release Activity

11 11 © 2007 Electric Power Research Institute, Inc. All rights reserved. SVES Model Principal Parameters –Soil Gas Velocity, –Air Permeability, and –Pressure Gradient.

12 12 © 2007 Electric Power Research Institute, Inc. All rights reserved. Model Assumptions The thickness of the vadose zone is relatively constant, homogeneous and isotropic within the extraction point’s ROI, i.e. construction backfill. An impervious or semi-pervious surface barrier to atmospheric gas transfer and direct infiltration of precipitation to the vadose zone is in place, i.e. pavement or concrete. A detection or change in condensate activity concentration is due to a soil vapor plume entering the ROI of an extraction point and is not the result of diffuse background H-3 activity in the soil. The approximate cross-sectional area OR volume of contaminated soil AND the approximate distance from the extraction point can be determined. Soil vapor within the capillary fringe of the liquid plume has the same activity concentration as the liquid release.

13 13 © 2007 Electric Power Research Institute, Inc. All rights reserved. Conceptual Design Each Extraction Capable of Covering Large Areas

14 14 © 2007 Electric Power Research Institute, Inc. All rights reserved. Specific Discharge and Capture Ratio Specific Discharge Within Plume Front Total Discharge at Plume Front, Q r Geometric Capture Ratio,

15 15 © 2007 Electric Power Research Institute, Inc. All rights reserved. Ideal and Non-Ideal Conditions System is More Effective with Concrete or Asphalt Cover

16 16 © 2007 Electric Power Research Institute, Inc. All rights reserved. Cylinder-Sphere Model – Non-Ideal Total Surface Area

17 17 © 2007 Electric Power Research Institute, Inc. All rights reserved. Additional Model Considerations Thick Vadose Zone 3-D Rendering to Determine Shape Surface Areas

18 18 © 2007 Electric Power Research Institute, Inc. All rights reserved. SVES Benefits Fewer GW Monitoring Wells More Effective Sentry System Onsite Analysis for H-3 More Effective Early Warning Methodology Less Dependent on Precise Placement Less Invasive (Push-Probe Installation Method) than Traditional GW Monitoring Well

19 19 © 2007 Electric Power Research Institute, Inc. All rights reserved. Project Schedule Phase 1 – Complete Phase 2 – 12/31/2007 Phase 3 & 4 – 12/31/2008


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