Moffett EATS Evaluation Presentation to RAB July 12, 2007
Upcoming SlideShare
Loading in...5
×
 

Moffett EATS Evaluation Presentation to RAB July 12, 2007

on

  • 1,057 views

 

Statistics

Views

Total Views
1,057
Views on SlideShare
1,049
Embed Views
8

Actions

Likes
0
Downloads
16
Comments
0

3 Embeds 8

http://localhost 4
http://www.nuqu.org 2
http://www.slideshare.net 2

Accessibility

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    Moffett EATS Evaluation Presentation to RAB July 12, 2007 Moffett EATS Evaluation Presentation to RAB July 12, 2007 Presentation Transcript

    • Site 26 Evaluation RAB Presentation Former Naval Air Station Moffett Field July 12, 2007 Presented by: Liz Barr Navy Remedial Project Manager
    • Presentation Outline • Background • Evaluation Objectives – Phase I – Phase II • Results • Summary, Conclusions, and Recommendations • Schedule
    • BACKGROUND
    • Background • Site 26 Record of Decision 1996 - GW Monitoring, Institutional Controls, and Extraction and Treatment of GW • COCs - PCE - VC - TCE - 1,2-DCA - Cis-1,2-DCE - 1,1-DCE • East-side Aquifer Treatment System (EATS) operational Jan. 1999 - July 2003 – Recovered <0.5 lbs/month of VOCs – Decreasing monthly recovery – Cost >$29,000 per lb of VOCs • EATS 5-year review noted that pump and treat may not be efficient, and recommended evaluating alternatives
    • East-side Aquifer Treatment System
    • EVALUATION OBJECTIVES
    • Evaluation Objectives • Per the 5-year Review evaluation of other clean-up alternatives • Developed Work Plan – Jan. 2003 • Work Plan activities divided into two phases – Phase I • Evaluate geology / aquifer hydraulics • Assess potential COC rebound • Evaluate plume stability • Groundwater sampling – Phase II • Conduct nutrient enhancement pilot test • Groundwater sampling
    • PHASE I
    • Evaluation of Geology
    • Evaluation of Geology Results - Cross Section A-A’
    • Well / Aquifer Testing • Performed recovery tests on each extraction well • Turned off wells one at a time. Measured water level responses in surrounding wells Results ● No response related to direction ● Consistent with a coarse sand to fine gravel
    • Rebound / Plume Stability
    • Rebound / Plume Stability TCE Concentration Extraction wells off as of July 2003
    • Rebound / Plume Stability EXW-2 Plume Interior Well
    • Rebound / Plume Stability WU5-18 Plume Boundary Well
    • Natural Attenuation • Geochemical indicators support NA process – Low levels of dissolved oxygen, dissolved hydrogen and the presence of methane (supports anaerobic conditions) – Degradation products present • Natural attenuation is occurring • Degradation rate slow
    • Natural Attenuation Breakdown Products
    • PHASE II
    • Enhanced Natural Attenuation (HRC® Injection) • Conducted nutrient enhancement (NE) pilot test • Injected Hydrogen Release Compound (HRC®) at two groundwater “hot spots” to evaluate the ability for NE to reduce VOCs
    • Enhanced Natural Attenuation HRC® Placement • Pilot test targeted two separate areas • HRC® injected Feb.-March 2005 • Injected 7 to 32 ft below ground surface • 81 injection points (36 at PS-1 and 45 at PS-2)
    • Enhanced Natural Attenuation Location of HRC ® Injections and Monitoring Wells Treatment System
    • Enhanced Natural Attenuation Sampling Schedule • 13 wells sampled 12 times over 18 months • Sampled chemistry monthly through Sept. 2005 then quarterly until Sept. 2006 • Analyzed for VOCs, lactate, and NA parameters • Sampled select wells for microbial parameters and specific dechlorinating bacteria. Sampled 5 times June 2005 – Sept. 2006
    • RESULTS
    • Extent of TCE Plume Over Time
    • Extent of CIS-1,2-DCE Plume Over Time
    • Extent of VC Plume Over Time
    • W7-10, Within PS-1 Area TCE Concentration vs. Time
    • EXW-2, Within PS-2 Area TCE Concentration vs. Time
    • Bacterial Analysis • Suitable native bacteria present for reductive dechlorination across entire site • Added substrate (HRC®) stimulated microbes in pilot test areas, reducing VOCs to less than 50 µg/L • HRC® had limited impact in pilot test areas where VOCs were less than 50 µg/L
    • SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS
    • Summary • 1,2-DCA remained below the ROD cleanup standard of 0.5 µg/L, except at 2 wells • 1,1-DCE remained below the ROD cleanup standard of 6 µg/L, except at 1 well • Other COCs generally at low concentrations • Natural attenuation is taking place. Native bacteria for dechlorination are present • HRC® reduced VOC concentrations to < 50 µg/L in pilot test areas. HRC® not effective when concentrations of VOCs < 50 µg/L
    • Conclusions • Very low VOC concentrations remaining • No VOC rebound • Stable VOC plumes • Low potential risk
    • Recommendations Based on the plume stability, no contaminant rebound and low potential risk, the Navy recommends: – EATS remain turned off and on standby – Monitored natural attenuation (MNA) implemented for completing remediation of groundwater at site
    • Schedule • Prepared and submitted a Draft Completion Report – June 2007 • Final Completion Report – fall/winter 2007