moffett rab site 26 and 28 update
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Abiotic / Biotic Treatability Study
Restoration Advisory Board Meeting
May 13, 2010
Installation Restoration Sites 26 and 28
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.
Conduct Pilot Test in area of highest CE concentration in upper A-Aquifer at Site 26
Treatability Study Method:
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
Biologically Mediated Oxidation - Reduction
Electron Donor Electron AcceptorResistor
Battery Ground
GrowthProtein Synthesis
Reproduction
CnHn
Fe(II)
H2S
H2
O2
NO3
As(V)
Mn(IV)
SO4
CO2
WorkLight bulb
Motors
Fe(0)
CO2 + H2O
Fe(III)
H2O +SO4
H2O
FeS2Fe (III)
Fe(II)
Fe(III)+SO4
H2O + CO2
HNO2
As(III)
Mn(II)
Fe (II)
S- + H2O
CH4
Reduced Oxidized Reduced Oxidized
Biological Reductive Dechlorination of Chlorinated Ethenes
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
H H H HH H
PCETCE
cis 1,2 -DCE
HH
H H HHHH HH H H
VC
H H
H H H H
Ethene
0
- 50
- 200
- 150
- 250
ORP
HHHHHH
C C C C C C
Ethane-300
PCETCE
cis 1,2 -DCEVC
EtheneEthane
PCETCE
cis 1,2 -DCEVC
EtheneEthane
HH
C CCl
Cl
Cl
Cl
Fe2+
TetrachloroetheneDichloroacetylene
Ethene
Ethane
Fe0Fe2+
Fe2+
Fe0
Abiotic Pathway
Fe2+
Fe2+
Fe0Fe0
Fe0
Fe0
O
O HH
O HH
O HH
O HH
O HH
O HH
O HH
Chloroacetylene
Acetylene
Some Hypothesized Reaction Pathways
Biotic Abiotic
PCE
TCE
cis 1,2-DCE trans 1,2-DCE
VC
Ethene
Ethane
PCE
TCE
VC
Ethene
Ethane
Chloroacetylene
Acetylene
1,1-DCE, trans 1,2-DCE, cis1,2-DCE
Dichloroacetylene
Hydrogenolysis
β-elimination
α-elimination
Hydrogenation
10
Indicators of Degradation Pathway
• Chloroacetylene
• Dichloroacetylene
Abiotic Pathway
• Acetylene
• 1,1-DCE
Biotic Pathway
• Primarily cis 1,2-DCE
• Low TCE, DCE, VC / ethene ratio• Stoichiometric Conversion
EHC Injection Process
GW FlowDirection
Groundwater Flow
Radius of EHC Distribution Evaluation
Groundwater Flow Direction
Relative Molar Fraction of Ethenes and Ethane
Upgradient Well
Treatment Area Wells
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.
• Dechlorinating microbial culture (DHC) is present in the treatment area.
• Complete conversion of CEs to non-toxic degradation products is occurring.
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
28
Conduct Concurrent Pilot Tests in Three High Concentration Areas:
Evaluate Three Technologies:
In Situ Anaerobic Biotic/Abiotic Degradation (ISABA)
In Situ Anaerobic Biostimulation with Bioaugmentation (ISABB) Process
Building 88 Area
Traffic Island Area
Well W9-18 Area
Sodium Lactate & SDC-9
Emulsified Oil & SDC-9
Expanded Pilot Test (Site 28) Methodology
EHC
ISABA - EHC
ISABB - Emulsfied Oil & SDC-9
ISABB - Lactate & SDC-9
Task 1 Conduct MIPs Investigation
Task 2 Install Monitoring Wells
Task 3 Inject Substrates
Expanded Pilot Test Site 28
30
Site 28 Pilot Test Schedule
February 2010 - Work Plans Finalized
March 2010 - MIPs Investigation
May 2010 -Treatability Study Progress Report
July, 2010 - Substrate Injection
August 2010 to July 2011 - Performance Monitoring
October 2011 – Treatability Study Final Report
June, 2010 – Monitoring Well Installation
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