Presentation to the Moffett Field Restoration Advisory Board May 13, 2010: Update on Sites 26 and 28, Dan Leigh, Shaw Environmental and Infrastructure

1. Installation Restoration Sites 26 and 28
Abiotic / Biotic Treatability Study
Restoration Advisory Board Meeting
May 13, 2010

2. IR Site 26 Treatability Study
Purpose of Treatability Test
Determine if combined abiotic/biotic treatment is a viable remedial alternative
for mitigating the remaining chlorinated ethenes (CEs) present in the upper
portion of the A-aquifer at IR Site 26.
Treatability Study Method:
Conduct Pilot Test in area of highest CE concentration in upper A-Aquifer at
Site 26
Pilot Test Method:
Install wells in Pilot Test area
Determine baseline conditions in pilot test area
Inject EHC® into Aquifer
Measure Distribution of EHC®
Measure changes in pilot test area geochemistry
Measure changes in pilot test area CE concentrations
2

6. Biologically Mediated Oxidation - Reduction
Work Growth
Light bulb Protein Synthesis
Motors Reproduction
Resistor
Electron Donor Reduced
Electron Acceptor
Oxidized
Reduced
Battery Oxidized
Ground
CnHn CO2 + H2O H2O + CO2 O2
Fe(II) Fe(III) HNO2 NO3
Fe(II) As(III) As(V)
Fe(0)
Mn(II) Mn(IV)
FeS2 Fe(III)+SO4
Fe (II) Fe (III)
H2S H2O +SO4
S- + H 2 O SO4
H2 H2O
CH4 CO2

7. Biological Reductive Dechlorination of Chlorinated Ethenes
ORP
0
- 50
H Cl
H H H
Cl H
H Cl HH
Cl H
H Cl Cl
HH
- 150 C C C C C C
H
H Cl HH
Cl
H
H Cl HH
Cl H Cl
H H H
Cl
- 200
PCE PCE PCE
TCE TCE TCE
- 250 cis 1,2 -DCE cis 1,2 -DCE cis 1,2 -DCE
VC VC VC
Ethene Ethene Ethene
-300
Ethane Ethane Ethane

8. O H Abiotic Pathway
H
O H
H
H
O H
Fe0 Fe
0
Fe2+
H
O H Fe0
Fe2+
Fe0
Fe 2+ Fe
0
Fe2+ H
O H
H O
Fe2+
Cl Cl
H
C C
Cl Cl
O H
H
O H
H
Tetrachloroethene
Dichloroacetylene
Chloroacetylene
Acetylene
Ethene
Ethane

9. Some Hypothesized Reaction Pathways
Biotic Abiotic
PCE PCE
TCE Dichloroacetylene
TCE
cis 1,2-DCE trans 1,2-DCE 1,1-DCE, trans 1,2-DCE, cis1,2-DCE
Chloroacetylene
VC
VC
Ethene Ethene Acetylene
Ethane Ethane
α-elimination Hydrogenolysis
β-elimination Hydrogenation

10. Indicators of Degradation Pathway
Biotic Pathway Abiotic Pathway
• Dichloroacetylene
• Chloroacetylene
• Primarily cis 1,2-DCE • Acetylene
• 1,1-DCE
• Stoichiometric Conversion
• Low TCE, DCE, VC / ethene ratio
10

12. EHC Injection Process
GW Flow
Direction

13. Groundwater Flow

14. Radius of EHC Distribution Evaluation

15. Groundwater Flow

24. Relative Molar Fraction of Ethenes and Ethane
Upgradient Well
Treatment Area Wells

25. Relative Molar Fraction of Ethenes and Ethane

26. Preliminary Conclusions Site 26 TS
• pH, ORP, SC, T, in the treatment area are within the range
considered appropriate for biotic and abiotic degradation of the CEs
• DO, nitrate, arsenic, manganese, iron, sulfate and methane reducing
conditions have been established in the treatment area.
• Degradation of CEs is occurring.
• Cis 1,2-DCE stall is not occurring.
• Complete conversion of CEs to non-toxic degradation products is
occurring.
• Dechlorinating microbial culture (DHC) is present in the treatment
area.
26

27. 26 Treatability Study Schedule
June 28, 2010 – 4th Quarter GW Sampling Event
August 25, 2010 -Draft Treatability Study Results Technical Memorandum
October 27, 2010 -Final Treatability Study Results Technical Memorandum
27

28. Expanded Pilot Test (Site 28) Methodology
Evaluate Three Technologies:
In Situ Anaerobic Biotic/Abiotic Degradation (ISABA)
EHC
In Situ Anaerobic Biostimulation with Bioaugmentation (ISABB) Process
Sodium Lactate & SDC-9
Emulsified Oil & SDC-9
Conduct Concurrent Pilot Tests in Three High Concentration Areas:
Building 88 Area
Traffic Island Area
Well W9-18 Area
28

29. Expanded Pilot Test Site 28
ISABB - Emulsfied
Oil & SDC-9
ISABA - EHC
Task 1 Conduct MIPs
Investigation
Task 2 Install Monitoring
ISABB - Lactate &
SDC-9 Wells
Task 3 Inject Substrates

30. Site 28 Pilot Test Schedule
February 2010 - Work Plans Finalized
March 2010 - MIPs Investigation
May 2010 -Treatability Study Progress Report
June, 2010 – Monitoring Well Installation
July, 2010 - Substrate Injection
August 2010 to July 2011 - Performance Monitoring
October 2011 – Treatability Study Final Report
30